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linux/fs/io_uring.c
Jens Axboe eacc6dfaea io_uring: remove punt of short reads to async context 
We currently punt any short read on a regular file to async context,
but this fails if the short read is due to running into EOF. This is
especially problematic since we only do the single prep for commands
now, as we don't reset kiocb->ki_pos. This can result in a 4k read on
a 1k file returning zero, as we detect the short read and then retry
from async context. At the time of retry, the position is now 1k, and
we end up reading nothing, and hence return 0.

Instead of trying to patch around the fact that short reads can be
legitimate and won't succeed in case of retry, remove the logic to punt
a short read to async context. Simply return it.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-01-07 13:08:56 -07:00

5515 lines
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// SPDX-License-Identifier: GPL-2.0
/*
* Shared application/kernel submission and completion ring pairs, for
* supporting fast/efficient IO.
*
* A note on the read/write ordering memory barriers that are matched between
* the application and kernel side.
*
* After the application reads the CQ ring tail, it must use an
* appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
* before writing the tail (using smp_load_acquire to read the tail will
* do). It also needs a smp_mb() before updating CQ head (ordering the
* entry load(s) with the head store), pairing with an implicit barrier
* through a control-dependency in io_get_cqring (smp_store_release to
* store head will do). Failure to do so could lead to reading invalid
* CQ entries.
*
* Likewise, the application must use an appropriate smp_wmb() before
* writing the SQ tail (ordering SQ entry stores with the tail store),
* which pairs with smp_load_acquire in io_get_sqring (smp_store_release
* to store the tail will do). And it needs a barrier ordering the SQ
* head load before writing new SQ entries (smp_load_acquire to read
* head will do).
*
* When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
* needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
* updating the SQ tail; a full memory barrier smp_mb() is needed
* between.
*
* Also see the examples in the liburing library:
*
* git://git.kernel.dk/liburing
*
* io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
* from data shared between the kernel and application. This is done both
* for ordering purposes, but also to ensure that once a value is loaded from
* data that the application could potentially modify, it remains stable.
*
* Copyright (C) 2018-2019 Jens Axboe
* Copyright (c) 2018-2019 Christoph Hellwig
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <linux/refcount.h>
#include <linux/uio.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mmu_context.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/blkdev.h>
#include <linux/bvec.h>
#include <linux/net.h>
#include <net/sock.h>
#include <net/af_unix.h>
#include <net/scm.h>
#include <linux/anon_inodes.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include <linux/sizes.h>
#include <linux/hugetlb.h>
#include <linux/highmem.h>
#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "internal.h"
#include "io-wq.h"
#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
/*
* Shift of 9 is 512 entries, or exactly one page on 64-bit archs
*/
#define IORING_FILE_TABLE_SHIFT 9
#define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT)
#define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1)
#define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE)
struct io_uring {
u32 head ____cacheline_aligned_in_smp;
u32 tail ____cacheline_aligned_in_smp;
};
/*
* This data is shared with the application through the mmap at offsets
* IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
*
* The offsets to the member fields are published through struct
* io_sqring_offsets when calling io_uring_setup.
*/
struct io_rings {
/*
* Head and tail offsets into the ring; the offsets need to be
* masked to get valid indices.
*
* The kernel controls head of the sq ring and the tail of the cq ring,
* and the application controls tail of the sq ring and the head of the
* cq ring.
*/
struct io_uring sq, cq;
/*
* Bitmasks to apply to head and tail offsets (constant, equals
* ring_entries - 1)
*/
u32 sq_ring_mask, cq_ring_mask;
/* Ring sizes (constant, power of 2) */
u32 sq_ring_entries, cq_ring_entries;
/*
* Number of invalid entries dropped by the kernel due to
* invalid index stored in array
*
* Written by the kernel, shouldn't be modified by the
* application (i.e. get number of "new events" by comparing to
* cached value).
*
* After a new SQ head value was read by the application this
* counter includes all submissions that were dropped reaching
* the new SQ head (and possibly more).
*/
u32 sq_dropped;
/*
* Runtime flags
*
* Written by the kernel, shouldn't be modified by the
* application.
*
* The application needs a full memory barrier before checking
* for IORING_SQ_NEED_WAKEUP after updating the sq tail.
*/
u32 sq_flags;
/*
* Number of completion events lost because the queue was full;
* this should be avoided by the application by making sure
* there are not more requests pending than there is space in
* the completion queue.
*
* Written by the kernel, shouldn't be modified by the
* application (i.e. get number of "new events" by comparing to
* cached value).
*
* As completion events come in out of order this counter is not
* ordered with any other data.
*/
u32 cq_overflow;
/*
* Ring buffer of completion events.
*
* The kernel writes completion events fresh every time they are
* produced, so the application is allowed to modify pending
* entries.
*/
struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
};
struct io_mapped_ubuf {
u64 ubuf;
size_t len;
struct bio_vec *bvec;
unsigned int nr_bvecs;
};
struct fixed_file_table {
struct file **files;
};
struct io_ring_ctx {
struct {
struct percpu_ref refs;
} ____cacheline_aligned_in_smp;
struct {
unsigned int flags;
bool compat;
bool account_mem;
bool cq_overflow_flushed;
bool drain_next;
/*
* Ring buffer of indices into array of io_uring_sqe, which is
* mmapped by the application using the IORING_OFF_SQES offset.
*
* This indirection could e.g. be used to assign fixed
* io_uring_sqe entries to operations and only submit them to
* the queue when needed.
*
* The kernel modifies neither the indices array nor the entries
* array.
*/
u32 *sq_array;
unsigned cached_sq_head;
unsigned sq_entries;
unsigned sq_mask;
unsigned sq_thread_idle;
unsigned cached_sq_dropped;
atomic_t cached_cq_overflow;
struct io_uring_sqe *sq_sqes;
struct list_head defer_list;
struct list_head timeout_list;
struct list_head cq_overflow_list;
wait_queue_head_t inflight_wait;
} ____cacheline_aligned_in_smp;
struct io_rings *rings;
/* IO offload */
struct io_wq *io_wq;
struct task_struct *sqo_thread; /* if using sq thread polling */
struct mm_struct *sqo_mm;
wait_queue_head_t sqo_wait;
/*
* If used, fixed file set. Writers must ensure that ->refs is dead,
* readers must ensure that ->refs is alive as long as the file* is
* used. Only updated through io_uring_register(2).
*/
struct fixed_file_table *file_table;
unsigned nr_user_files;
/* if used, fixed mapped user buffers */
unsigned nr_user_bufs;
struct io_mapped_ubuf *user_bufs;
struct user_struct *user;
const struct cred *creds;
/* 0 is for ctx quiesce/reinit/free, 1 is for sqo_thread started */
struct completion *completions;
/* if all else fails... */
struct io_kiocb *fallback_req;
#if defined(CONFIG_UNIX)
struct socket *ring_sock;
#endif
struct {
unsigned cached_cq_tail;
unsigned cq_entries;
unsigned cq_mask;
atomic_t cq_timeouts;
struct wait_queue_head cq_wait;
struct fasync_struct *cq_fasync;
struct eventfd_ctx *cq_ev_fd;
} ____cacheline_aligned_in_smp;
struct {
struct mutex uring_lock;
wait_queue_head_t wait;
} ____cacheline_aligned_in_smp;
struct {
spinlock_t completion_lock;
bool poll_multi_file;
/*
* ->poll_list is protected by the ctx->uring_lock for
* io_uring instances that don't use IORING_SETUP_SQPOLL.
* For SQPOLL, only the single threaded io_sq_thread() will
* manipulate the list, hence no extra locking is needed there.
*/
struct list_head poll_list;
struct hlist_head *cancel_hash;
unsigned cancel_hash_bits;
spinlock_t inflight_lock;
struct list_head inflight_list;
} ____cacheline_aligned_in_smp;
};
/*
* First field must be the file pointer in all the
* iocb unions! See also 'struct kiocb' in <linux/fs.h>
*/
struct io_poll_iocb {
struct file *file;
union {
struct wait_queue_head *head;
u64 addr;
};
__poll_t events;
bool done;
bool canceled;
struct wait_queue_entry wait;
};
struct io_timeout_data {
struct io_kiocb *req;
struct hrtimer timer;
struct timespec64 ts;
enum hrtimer_mode mode;
u32 seq_offset;
};
struct io_accept {
struct file *file;
struct sockaddr __user *addr;
int __user *addr_len;
int flags;
};
struct io_sync {
struct file *file;
loff_t len;
loff_t off;
int flags;
};
struct io_cancel {
struct file *file;
u64 addr;
};
struct io_timeout {
struct file *file;
u64 addr;
int flags;
unsigned count;
};
struct io_rw {
/* NOTE: kiocb has the file as the first member, so don't do it here */
struct kiocb kiocb;
u64 addr;
u64 len;
};
struct io_connect {
struct file *file;
struct sockaddr __user *addr;
int addr_len;
};
struct io_sr_msg {
struct file *file;
struct user_msghdr __user *msg;
int msg_flags;
};
struct io_async_connect {
struct sockaddr_storage address;
};
struct io_async_msghdr {
struct iovec fast_iov[UIO_FASTIOV];
struct iovec *iov;
struct sockaddr __user *uaddr;
struct msghdr msg;
};
struct io_async_rw {
struct iovec fast_iov[UIO_FASTIOV];
struct iovec *iov;
ssize_t nr_segs;
ssize_t size;
};
struct io_async_ctx {
union {
struct io_async_rw rw;
struct io_async_msghdr msg;
struct io_async_connect connect;
struct io_timeout_data timeout;
};
};
/*
* NOTE! Each of the iocb union members has the file pointer
* as the first entry in their struct definition. So you can
* access the file pointer through any of the sub-structs,
* or directly as just 'ki_filp' in this struct.
*/
struct io_kiocb {
union {
struct file *file;
struct io_rw rw;
struct io_poll_iocb poll;
struct io_accept accept;
struct io_sync sync;
struct io_cancel cancel;
struct io_timeout timeout;
struct io_connect connect;
struct io_sr_msg sr_msg;
};
struct io_async_ctx *io;
struct file *ring_file;
int ring_fd;
bool has_user;
bool in_async;
bool needs_fixed_file;
u8 opcode;
struct io_ring_ctx *ctx;
union {
struct list_head list;
struct hlist_node hash_node;
};
struct list_head link_list;
unsigned int flags;
refcount_t refs;
#define REQ_F_NOWAIT 1 /* must not punt to workers */
#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */
#define REQ_F_FIXED_FILE 4 /* ctx owns file */
#define REQ_F_LINK_NEXT 8 /* already grabbed next link */
#define REQ_F_IO_DRAIN 16 /* drain existing IO first */
#define REQ_F_IO_DRAINED 32 /* drain done */
#define REQ_F_LINK 64 /* linked sqes */
#define REQ_F_LINK_TIMEOUT 128 /* has linked timeout */
#define REQ_F_FAIL_LINK 256 /* fail rest of links */
#define REQ_F_DRAIN_LINK 512 /* link should be fully drained */
#define REQ_F_TIMEOUT 1024 /* timeout request */
#define REQ_F_ISREG 2048 /* regular file */
#define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */
#define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */
#define REQ_F_INFLIGHT 16384 /* on inflight list */
#define REQ_F_COMP_LOCKED 32768 /* completion under lock */
#define REQ_F_HARDLINK 65536 /* doesn't sever on completion < 0 */
u64 user_data;
u32 result;
u32 sequence;
struct list_head inflight_entry;
struct io_wq_work work;
};
#define IO_PLUG_THRESHOLD 2
#define IO_IOPOLL_BATCH 8
struct io_submit_state {
struct blk_plug plug;
/*
* io_kiocb alloc cache
*/
void *reqs[IO_IOPOLL_BATCH];
unsigned int free_reqs;
unsigned int cur_req;
/*
* File reference cache
*/
struct file *file;
unsigned int fd;
unsigned int has_refs;
unsigned int used_refs;
unsigned int ios_left;
};
static void io_wq_submit_work(struct io_wq_work **workptr);
static void io_cqring_fill_event(struct io_kiocb *req, long res);
static void __io_free_req(struct io_kiocb *req);
static void io_put_req(struct io_kiocb *req);
static void io_double_put_req(struct io_kiocb *req);
static void __io_double_put_req(struct io_kiocb *req);
static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
static void io_queue_linked_timeout(struct io_kiocb *req);
static struct kmem_cache *req_cachep;
static const struct file_operations io_uring_fops;
struct sock *io_uring_get_socket(struct file *file)
{
#if defined(CONFIG_UNIX)
if (file->f_op == &io_uring_fops) {
struct io_ring_ctx *ctx = file->private_data;
return ctx->ring_sock->sk;
}
#endif
return NULL;
}
EXPORT_SYMBOL(io_uring_get_socket);
static void io_ring_ctx_ref_free(struct percpu_ref *ref)
{
struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
complete(&ctx->completions[0]);
}
static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
{
struct io_ring_ctx *ctx;
int hash_bits;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return NULL;
ctx->fallback_req = kmem_cache_alloc(req_cachep, GFP_KERNEL);
if (!ctx->fallback_req)
goto err;
ctx->completions = kmalloc(2 * sizeof(struct completion), GFP_KERNEL);
if (!ctx->completions)
goto err;
/*
* Use 5 bits less than the max cq entries, that should give us around
* 32 entries per hash list if totally full and uniformly spread.
*/
hash_bits = ilog2(p->cq_entries);
hash_bits -= 5;
if (hash_bits <= 0)
hash_bits = 1;
ctx->cancel_hash_bits = hash_bits;
ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
GFP_KERNEL);
if (!ctx->cancel_hash)
goto err;
__hash_init(ctx->cancel_hash, 1U << hash_bits);
if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
goto err;
ctx->flags = p->flags;
init_waitqueue_head(&ctx->cq_wait);
INIT_LIST_HEAD(&ctx->cq_overflow_list);
init_completion(&ctx->completions[0]);
init_completion(&ctx->completions[1]);
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->wait);
spin_lock_init(&ctx->completion_lock);
INIT_LIST_HEAD(&ctx->poll_list);
INIT_LIST_HEAD(&ctx->defer_list);
INIT_LIST_HEAD(&ctx->timeout_list);
init_waitqueue_head(&ctx->inflight_wait);
spin_lock_init(&ctx->inflight_lock);
INIT_LIST_HEAD(&ctx->inflight_list);
return ctx;
err:
if (ctx->fallback_req)
kmem_cache_free(req_cachep, ctx->fallback_req);
kfree(ctx->completions);
kfree(ctx->cancel_hash);
kfree(ctx);
return NULL;
}
static inline bool __req_need_defer(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
return req->sequence != ctx->cached_cq_tail + ctx->cached_sq_dropped
+ atomic_read(&ctx->cached_cq_overflow);
}
static inline bool req_need_defer(struct io_kiocb *req)
{
if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) == REQ_F_IO_DRAIN)
return __req_need_defer(req);
return false;
}
static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
req = list_first_entry_or_null(&ctx->defer_list, struct io_kiocb, list);
if (req && !req_need_defer(req)) {
list_del_init(&req->list);
return req;
}
return NULL;
}
static struct io_kiocb *io_get_timeout_req(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
req = list_first_entry_or_null(&ctx->timeout_list, struct io_kiocb, list);
if (req) {
if (req->flags & REQ_F_TIMEOUT_NOSEQ)
return NULL;
if (!__req_need_defer(req)) {
list_del_init(&req->list);
return req;
}
}
return NULL;
}
static void __io_commit_cqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
if (ctx->cached_cq_tail != READ_ONCE(rings->cq.tail)) {
/* order cqe stores with ring update */
smp_store_release(&rings->cq.tail, ctx->cached_cq_tail);
if (wq_has_sleeper(&ctx->cq_wait)) {
wake_up_interruptible(&ctx->cq_wait);
kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN);
}
}
}
static inline bool io_req_needs_user(struct io_kiocb *req)
{
return !(req->opcode == IORING_OP_READ_FIXED ||
req->opcode == IORING_OP_WRITE_FIXED);
}
static inline bool io_prep_async_work(struct io_kiocb *req,
struct io_kiocb **link)
{
bool do_hashed = false;
switch (req->opcode) {
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
/* only regular files should be hashed for writes */
if (req->flags & REQ_F_ISREG)
do_hashed = true;
/* fall-through */
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
case IORING_OP_SENDMSG:
case IORING_OP_RECVMSG:
case IORING_OP_ACCEPT:
case IORING_OP_POLL_ADD:
case IORING_OP_CONNECT:
/*
* We know REQ_F_ISREG is not set on some of these
* opcodes, but this enables us to keep the check in
* just one place.
*/
if (!(req->flags & REQ_F_ISREG))
req->work.flags |= IO_WQ_WORK_UNBOUND;
break;
}
if (io_req_needs_user(req))
req->work.flags |= IO_WQ_WORK_NEEDS_USER;
*link = io_prep_linked_timeout(req);
return do_hashed;
}
static inline void io_queue_async_work(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *link;
bool do_hashed;
do_hashed = io_prep_async_work(req, &link);
trace_io_uring_queue_async_work(ctx, do_hashed, req, &req->work,
req->flags);
if (!do_hashed) {
io_wq_enqueue(ctx->io_wq, &req->work);
} else {
io_wq_enqueue_hashed(ctx->io_wq, &req->work,
file_inode(req->file));
}
if (link)
io_queue_linked_timeout(link);
}
static void io_kill_timeout(struct io_kiocb *req)
{
int ret;
ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
if (ret != -1) {
atomic_inc(&req->ctx->cq_timeouts);
list_del_init(&req->list);
io_cqring_fill_event(req, 0);
io_put_req(req);
}
}
static void io_kill_timeouts(struct io_ring_ctx *ctx)
{
struct io_kiocb *req, *tmp;
spin_lock_irq(&ctx->completion_lock);
list_for_each_entry_safe(req, tmp, &ctx->timeout_list, list)
io_kill_timeout(req);
spin_unlock_irq(&ctx->completion_lock);
}
static void io_commit_cqring(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
while ((req = io_get_timeout_req(ctx)) != NULL)
io_kill_timeout(req);
__io_commit_cqring(ctx);
while ((req = io_get_deferred_req(ctx)) != NULL) {
req->flags |= REQ_F_IO_DRAINED;
io_queue_async_work(req);
}
}
static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
unsigned tail;
tail = ctx->cached_cq_tail;
/*
* writes to the cq entry need to come after reading head; the
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)
return NULL;
ctx->cached_cq_tail++;
return &rings->cqes[tail & ctx->cq_mask];
}
static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
{
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
if (waitqueue_active(&ctx->sqo_wait))
wake_up(&ctx->sqo_wait);
if (ctx->cq_ev_fd)
eventfd_signal(ctx->cq_ev_fd, 1);
}
/* Returns true if there are no backlogged entries after the flush */
static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force)
{
struct io_rings *rings = ctx->rings;
struct io_uring_cqe *cqe;
struct io_kiocb *req;
unsigned long flags;
LIST_HEAD(list);
if (!force) {
if (list_empty_careful(&ctx->cq_overflow_list))
return true;
if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) ==
rings->cq_ring_entries))
return false;
}
spin_lock_irqsave(&ctx->completion_lock, flags);
/* if force is set, the ring is going away. always drop after that */
if (force)
ctx->cq_overflow_flushed = true;
cqe = NULL;
while (!list_empty(&ctx->cq_overflow_list)) {
cqe = io_get_cqring(ctx);
if (!cqe && !force)
break;
req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb,
list);
list_move(&req->list, &list);
if (cqe) {
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, req->result);
WRITE_ONCE(cqe->flags, 0);
} else {
WRITE_ONCE(ctx->rings->cq_overflow,
atomic_inc_return(&ctx->cached_cq_overflow));
}
}
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
while (!list_empty(&list)) {
req = list_first_entry(&list, struct io_kiocb, list);
list_del(&req->list);
io_put_req(req);
}
return cqe != NULL;
}
static void io_cqring_fill_event(struct io_kiocb *req, long res)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_cqe *cqe;
trace_io_uring_complete(ctx, req->user_data, res);
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
cqe = io_get_cqring(ctx);
if (likely(cqe)) {
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, 0);
} else if (ctx->cq_overflow_flushed) {
WRITE_ONCE(ctx->rings->cq_overflow,
atomic_inc_return(&ctx->cached_cq_overflow));
} else {
refcount_inc(&req->refs);
req->result = res;
list_add_tail(&req->list, &ctx->cq_overflow_list);
}
}
static void io_cqring_add_event(struct io_kiocb *req, long res)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
io_cqring_fill_event(req, res);
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
}
static inline bool io_is_fallback_req(struct io_kiocb *req)
{
return req == (struct io_kiocb *)
((unsigned long) req->ctx->fallback_req & ~1UL);
}
static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
req = ctx->fallback_req;
if (!test_and_set_bit_lock(0, (unsigned long *) ctx->fallback_req))
return req;
return NULL;
}
static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
struct io_kiocb *req;
if (!percpu_ref_tryget(&ctx->refs))
return NULL;
if (!state) {
req = kmem_cache_alloc(req_cachep, gfp);
if (unlikely(!req))
goto fallback;
} else if (!state->free_reqs) {
size_t sz;
int ret;
sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs);
/*
* Bulk alloc is all-or-nothing. If we fail to get a batch,
* retry single alloc to be on the safe side.
*/
if (unlikely(ret <= 0)) {
state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
if (!state->reqs[0])
goto fallback;
ret = 1;
}
state->free_reqs = ret - 1;
state->cur_req = 1;
req = state->reqs[0];
} else {
req = state->reqs[state->cur_req];
state->free_reqs--;
state->cur_req++;
}
got_it:
req->io = NULL;
req->ring_file = NULL;
req->file = NULL;
req->ctx = ctx;
req->flags = 0;
/* one is dropped after submission, the other at completion */
refcount_set(&req->refs, 2);
req->result = 0;
INIT_IO_WORK(&req->work, io_wq_submit_work);
return req;
fallback:
req = io_get_fallback_req(ctx);
if (req)
goto got_it;
percpu_ref_put(&ctx->refs);
return NULL;
}
static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr)
{
if (*nr) {
kmem_cache_free_bulk(req_cachep, *nr, reqs);
percpu_ref_put_many(&ctx->refs, *nr);
*nr = 0;
}
}
static void __io_free_req(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
if (req->io)
kfree(req->io);
if (req->file && !(req->flags & REQ_F_FIXED_FILE))
fput(req->file);
if (req->flags & REQ_F_INFLIGHT) {
unsigned long flags;
spin_lock_irqsave(&ctx->inflight_lock, flags);
list_del(&req->inflight_entry);
if (waitqueue_active(&ctx->inflight_wait))
wake_up(&ctx->inflight_wait);
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
}
percpu_ref_put(&ctx->refs);
if (likely(!io_is_fallback_req(req)))
kmem_cache_free(req_cachep, req);
else
clear_bit_unlock(0, (unsigned long *) ctx->fallback_req);
}
static bool io_link_cancel_timeout(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
if (ret != -1) {
io_cqring_fill_event(req, -ECANCELED);
io_commit_cqring(ctx);
req->flags &= ~REQ_F_LINK;
io_put_req(req);
return true;
}
return false;
}
static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
{
struct io_ring_ctx *ctx = req->ctx;
bool wake_ev = false;
/* Already got next link */
if (req->flags & REQ_F_LINK_NEXT)
return;
/*
* The list should never be empty when we are called here. But could
* potentially happen if the chain is messed up, check to be on the
* safe side.
*/
while (!list_empty(&req->link_list)) {
struct io_kiocb *nxt = list_first_entry(&req->link_list,
struct io_kiocb, link_list);
if (unlikely((req->flags & REQ_F_LINK_TIMEOUT) &&
(nxt->flags & REQ_F_TIMEOUT))) {
list_del_init(&nxt->link_list);
wake_ev |= io_link_cancel_timeout(nxt);
req->flags &= ~REQ_F_LINK_TIMEOUT;
continue;
}
list_del_init(&req->link_list);
if (!list_empty(&nxt->link_list))
nxt->flags |= REQ_F_LINK;
*nxtptr = nxt;
break;
}
req->flags |= REQ_F_LINK_NEXT;
if (wake_ev)
io_cqring_ev_posted(ctx);
}
/*
* Called if REQ_F_LINK is set, and we fail the head request
*/
static void io_fail_links(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
while (!list_empty(&req->link_list)) {
struct io_kiocb *link = list_first_entry(&req->link_list,
struct io_kiocb, link_list);
list_del_init(&link->link_list);
trace_io_uring_fail_link(req, link);
if ((req->flags & REQ_F_LINK_TIMEOUT) &&
link->opcode == IORING_OP_LINK_TIMEOUT) {
io_link_cancel_timeout(link);
} else {
io_cqring_fill_event(link, -ECANCELED);
__io_double_put_req(link);
}
req->flags &= ~REQ_F_LINK_TIMEOUT;
}
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
}
static void io_req_find_next(struct io_kiocb *req, struct io_kiocb **nxt)
{
if (likely(!(req->flags & REQ_F_LINK)))
return;
/*
* If LINK is set, we have dependent requests in this chain. If we
* didn't fail this request, queue the first one up, moving any other
* dependencies to the next request. In case of failure, fail the rest
* of the chain.
*/
if (req->flags & REQ_F_FAIL_LINK) {
io_fail_links(req);
} else if ((req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_COMP_LOCKED)) ==
REQ_F_LINK_TIMEOUT) {
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
/*
* If this is a timeout link, we could be racing with the
* timeout timer. Grab the completion lock for this case to
* protect against that.
*/
spin_lock_irqsave(&ctx->completion_lock, flags);
io_req_link_next(req, nxt);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
} else {
io_req_link_next(req, nxt);
}
}
static void io_free_req(struct io_kiocb *req)
{
struct io_kiocb *nxt = NULL;
io_req_find_next(req, &nxt);
__io_free_req(req);
if (nxt)
io_queue_async_work(nxt);
}
/*
* Drop reference to request, return next in chain (if there is one) if this
* was the last reference to this request.
*/
__attribute__((nonnull))
static void io_put_req_find_next(struct io_kiocb *req, struct io_kiocb **nxtptr)
{
io_req_find_next(req, nxtptr);
if (refcount_dec_and_test(&req->refs))
__io_free_req(req);
}
static void io_put_req(struct io_kiocb *req)
{
if (refcount_dec_and_test(&req->refs))
io_free_req(req);
}
/*
* Must only be used if we don't need to care about links, usually from
* within the completion handling itself.
*/
static void __io_double_put_req(struct io_kiocb *req)
{
/* drop both submit and complete references */
if (refcount_sub_and_test(2, &req->refs))
__io_free_req(req);
}
static void io_double_put_req(struct io_kiocb *req)
{
/* drop both submit and complete references */
if (refcount_sub_and_test(2, &req->refs))
io_free_req(req);
}
static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush)
{
struct io_rings *rings = ctx->rings;
/*
* noflush == true is from the waitqueue handler, just ensure we wake
* up the task, and the next invocation will flush the entries. We
* cannot safely to it from here.
*/
if (noflush && !list_empty(&ctx->cq_overflow_list))
return -1U;
io_cqring_overflow_flush(ctx, false);
/* See comment at the top of this file */
smp_rmb();
return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head);
}
static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
/* make sure SQ entry isn't read before tail */
return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
}
/*
* Find and free completed poll iocbs
*/
static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
struct list_head *done)
{
void *reqs[IO_IOPOLL_BATCH];
struct io_kiocb *req;
int to_free;
to_free = 0;
while (!list_empty(done)) {
req = list_first_entry(done, struct io_kiocb, list);
list_del(&req->list);
io_cqring_fill_event(req, req->result);
(*nr_events)++;
if (refcount_dec_and_test(&req->refs)) {
/* If we're not using fixed files, we have to pair the
* completion part with the file put. Use regular
* completions for those, only batch free for fixed
* file and non-linked commands.
*/
if (((req->flags & (REQ_F_FIXED_FILE|REQ_F_LINK)) ==
REQ_F_FIXED_FILE) && !io_is_fallback_req(req) &&
!req->io) {
reqs[to_free++] = req;
if (to_free == ARRAY_SIZE(reqs))
io_free_req_many(ctx, reqs, &to_free);
} else {
io_free_req(req);
}
}
}
io_commit_cqring(ctx);
io_free_req_many(ctx, reqs, &to_free);
}
static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min)
{
struct io_kiocb *req, *tmp;
LIST_HEAD(done);
bool spin;
int ret;
/*
* Only spin for completions if we don't have multiple devices hanging
* off our complete list, and we're under the requested amount.
*/
spin = !ctx->poll_multi_file && *nr_events < min;
ret = 0;
list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) {
struct kiocb *kiocb = &req->rw.kiocb;
/*
* Move completed entries to our local list. If we find a
* request that requires polling, break out and complete
* the done list first, if we have entries there.
*/
if (req->flags & REQ_F_IOPOLL_COMPLETED) {
list_move_tail(&req->list, &done);
continue;
}
if (!list_empty(&done))
break;
ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
if (ret < 0)
break;
if (ret && spin)
spin = false;
ret = 0;
}
if (!list_empty(&done))
io_iopoll_complete(ctx, nr_events, &done);
return ret;
}
/*
* Poll for a minimum of 'min' events. Note that if min == 0 we consider that a
* non-spinning poll check - we'll still enter the driver poll loop, but only
* as a non-spinning completion check.
*/
static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min)
{
while (!list_empty(&ctx->poll_list) && !need_resched()) {
int ret;
ret = io_do_iopoll(ctx, nr_events, min);
if (ret < 0)
return ret;
if (!min || *nr_events >= min)
return 0;
}
return 1;
}
/*
* We can't just wait for polled events to come to us, we have to actively
* find and complete them.
*/
static void io_iopoll_reap_events(struct io_ring_ctx *ctx)
{
if (!(ctx->flags & IORING_SETUP_IOPOLL))
return;
mutex_lock(&ctx->uring_lock);
while (!list_empty(&ctx->poll_list)) {
unsigned int nr_events = 0;
io_iopoll_getevents(ctx, &nr_events, 1);
/*
* Ensure we allow local-to-the-cpu processing to take place,
* in this case we need to ensure that we reap all events.
*/
cond_resched();
}
mutex_unlock(&ctx->uring_lock);
}
static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
long min)
{
int iters = 0, ret = 0;
do {
int tmin = 0;
/*
* Don't enter poll loop if we already have events pending.
* If we do, we can potentially be spinning for commands that
* already triggered a CQE (eg in error).
*/
if (io_cqring_events(ctx, false))
break;
/*
* If a submit got punted to a workqueue, we can have the
* application entering polling for a command before it gets
* issued. That app will hold the uring_lock for the duration
* of the poll right here, so we need to take a breather every
* now and then to ensure that the issue has a chance to add
* the poll to the issued list. Otherwise we can spin here
* forever, while the workqueue is stuck trying to acquire the
* very same mutex.
*/
if (!(++iters & 7)) {
mutex_unlock(&ctx->uring_lock);
mutex_lock(&ctx->uring_lock);
}
if (*nr_events < min)
tmin = min - *nr_events;
ret = io_iopoll_getevents(ctx, nr_events, tmin);
if (ret <= 0)
break;
ret = 0;
} while (min && !*nr_events && !need_resched());
return ret;
}
static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
long min)
{
int ret;
/*
* We disallow the app entering submit/complete with polling, but we
* still need to lock the ring to prevent racing with polled issue
* that got punted to a workqueue.
*/
mutex_lock(&ctx->uring_lock);
ret = __io_iopoll_check(ctx, nr_events, min);
mutex_unlock(&ctx->uring_lock);
return ret;
}
static void kiocb_end_write(struct io_kiocb *req)
{
/*
* Tell lockdep we inherited freeze protection from submission
* thread.
*/
if (req->flags & REQ_F_ISREG) {
struct inode *inode = file_inode(req->file);
__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
}
file_end_write(req->file);
}
static inline void req_set_fail_links(struct io_kiocb *req)
{
if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK)
req->flags |= REQ_F_FAIL_LINK;
}
static void io_complete_rw_common(struct kiocb *kiocb, long res)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if (res != req->result)
req_set_fail_links(req);
io_cqring_add_event(req, res);
}
static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
io_complete_rw_common(kiocb, res);
io_put_req(req);
}
static struct io_kiocb *__io_complete_rw(struct kiocb *kiocb, long res)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
struct io_kiocb *nxt = NULL;
io_complete_rw_common(kiocb, res);
io_put_req_find_next(req, &nxt);
return nxt;
}
static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if (res != req->result)
req_set_fail_links(req);
req->result = res;
if (res != -EAGAIN)
req->flags |= REQ_F_IOPOLL_COMPLETED;
}
/*
* After the iocb has been issued, it's safe to be found on the poll list.
* Adding the kiocb to the list AFTER submission ensures that we don't
* find it from a io_iopoll_getevents() thread before the issuer is done
* accessing the kiocb cookie.
*/
static void io_iopoll_req_issued(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
/*
* Track whether we have multiple files in our lists. This will impact
* how we do polling eventually, not spinning if we're on potentially
* different devices.
*/
if (list_empty(&ctx->poll_list)) {
ctx->poll_multi_file = false;
} else if (!ctx->poll_multi_file) {
struct io_kiocb *list_req;
list_req = list_first_entry(&ctx->poll_list, struct io_kiocb,
list);
if (list_req->file != req->file)
ctx->poll_multi_file = true;
}
/*
* For fast devices, IO may have already completed. If it has, add
* it to the front so we find it first.
*/
if (req->flags & REQ_F_IOPOLL_COMPLETED)
list_add(&req->list, &ctx->poll_list);
else
list_add_tail(&req->list, &ctx->poll_list);
}
static void io_file_put(struct io_submit_state *state)
{
if (state->file) {
int diff = state->has_refs - state->used_refs;
if (diff)
fput_many(state->file, diff);
state->file = NULL;
}
}
/*
* Get as many references to a file as we have IOs left in this submission,
* assuming most submissions are for one file, or at least that each file
* has more than one submission.
*/
static struct file *io_file_get(struct io_submit_state *state, int fd)
{
if (!state)
return fget(fd);
if (state->file) {
if (state->fd == fd) {
state->used_refs++;
state->ios_left--;
return state->file;
}
io_file_put(state);
}
state->file = fget_many(fd, state->ios_left);
if (!state->file)
return NULL;
state->fd = fd;
state->has_refs = state->ios_left;
state->used_refs = 1;
state->ios_left--;
return state->file;
}
/*
* If we tracked the file through the SCM inflight mechanism, we could support
* any file. For now, just ensure that anything potentially problematic is done
* inline.
*/
static bool io_file_supports_async(struct file *file)
{
umode_t mode = file_inode(file)->i_mode;
if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISSOCK(mode))
return true;
if (S_ISREG(mode) && file->f_op != &io_uring_fops)
return true;
return false;
}
static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe,
bool force_nonblock)
{
struct io_ring_ctx *ctx = req->ctx;
struct kiocb *kiocb = &req->rw.kiocb;
unsigned ioprio;
int ret;
if (!req->file)
return -EBADF;
if (S_ISREG(file_inode(req->file)->i_mode))
req->flags |= REQ_F_ISREG;
kiocb->ki_pos = READ_ONCE(sqe->off);
kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
ioprio = READ_ONCE(sqe->ioprio);
if (ioprio) {
ret = ioprio_check_cap(ioprio);
if (ret)
return ret;
kiocb->ki_ioprio = ioprio;
} else
kiocb->ki_ioprio = get_current_ioprio();
ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
if (unlikely(ret))
return ret;
/* don't allow async punt if RWF_NOWAIT was requested */
if ((kiocb->ki_flags & IOCB_NOWAIT) ||
(req->file->f_flags & O_NONBLOCK))
req->flags |= REQ_F_NOWAIT;
if (force_nonblock)
kiocb->ki_flags |= IOCB_NOWAIT;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!(kiocb->ki_flags & IOCB_DIRECT) ||
!kiocb->ki_filp->f_op->iopoll)
return -EOPNOTSUPP;
kiocb->ki_flags |= IOCB_HIPRI;
kiocb->ki_complete = io_complete_rw_iopoll;
req->result = 0;
} else {
if (kiocb->ki_flags & IOCB_HIPRI)
return -EINVAL;
kiocb->ki_complete = io_complete_rw;
}
req->rw.addr = READ_ONCE(sqe->addr);
req->rw.len = READ_ONCE(sqe->len);
/* we own ->private, reuse it for the buffer index */
req->rw.kiocb.private = (void *) (unsigned long)
READ_ONCE(sqe->buf_index);
return 0;
}
static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
{
switch (ret) {
case -EIOCBQUEUED:
break;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/*
* We can't just restart the syscall, since previously
* submitted sqes may already be in progress. Just fail this
* IO with EINTR.
*/
ret = -EINTR;
/* fall through */
default:
kiocb->ki_complete(kiocb, ret, 0);
}
}
static void kiocb_done(struct kiocb *kiocb, ssize_t ret, struct io_kiocb **nxt,
bool in_async)
{
if (in_async && ret >= 0 && kiocb->ki_complete == io_complete_rw)
*nxt = __io_complete_rw(kiocb, ret);
else
io_rw_done(kiocb, ret);
}
static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
struct iov_iter *iter)
{
struct io_ring_ctx *ctx = req->ctx;
size_t len = req->rw.len;
struct io_mapped_ubuf *imu;
unsigned index, buf_index;
size_t offset;
u64 buf_addr;
/* attempt to use fixed buffers without having provided iovecs */
if (unlikely(!ctx->user_bufs))
return -EFAULT;
buf_index = (unsigned long) req->rw.kiocb.private;
if (unlikely(buf_index >= ctx->nr_user_bufs))
return -EFAULT;
index = array_index_nospec(buf_index, ctx->nr_user_bufs);
imu = &ctx->user_bufs[index];
buf_addr = req->rw.addr;
/* overflow */
if (buf_addr + len < buf_addr)
return -EFAULT;
/* not inside the mapped region */
if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len)
return -EFAULT;
/*
* May not be a start of buffer, set size appropriately
* and advance us to the beginning.
*/
offset = buf_addr - imu->ubuf;
iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
if (offset) {
/*
* Don't use iov_iter_advance() here, as it's really slow for
* using the latter parts of a big fixed buffer - it iterates
* over each segment manually. We can cheat a bit here, because
* we know that:
*
* 1) it's a BVEC iter, we set it up
* 2) all bvecs are PAGE_SIZE in size, except potentially the
* first and last bvec
*
* So just find our index, and adjust the iterator afterwards.
* If the offset is within the first bvec (or the whole first
* bvec, just use iov_iter_advance(). This makes it easier
* since we can just skip the first segment, which may not
* be PAGE_SIZE aligned.
*/
const struct bio_vec *bvec = imu->bvec;
if (offset <= bvec->bv_len) {
iov_iter_advance(iter, offset);
} else {
unsigned long seg_skip;
/* skip first vec */
offset -= bvec->bv_len;
seg_skip = 1 + (offset >> PAGE_SHIFT);
iter->bvec = bvec + seg_skip;
iter->nr_segs -= seg_skip;
iter->count -= bvec->bv_len + offset;
iter->iov_offset = offset & ~PAGE_MASK;
}
}
return len;
}
static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter)
{
void __user *buf = u64_to_user_ptr(req->rw.addr);
size_t sqe_len = req->rw.len;
u8 opcode;
opcode = req->opcode;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
*iovec = NULL;
return io_import_fixed(req, rw, iter);
}
/* buffer index only valid with fixed read/write */
if (req->rw.kiocb.private)
return -EINVAL;
if (req->io) {
struct io_async_rw *iorw = &req->io->rw;
*iovec = iorw->iov;
iov_iter_init(iter, rw, *iovec, iorw->nr_segs, iorw->size);
if (iorw->iov == iorw->fast_iov)
*iovec = NULL;
return iorw->size;
}
if (!req->has_user)
return -EFAULT;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV,
iovec, iter);
#endif
return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
}
/*
* For files that don't have ->read_iter() and ->write_iter(), handle them
* by looping over ->read() or ->write() manually.
*/
static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb,
struct iov_iter *iter)
{
ssize_t ret = 0;
/*
* Don't support polled IO through this interface, and we can't
* support non-blocking either. For the latter, this just causes
* the kiocb to be handled from an async context.
*/
if (kiocb->ki_flags & IOCB_HIPRI)
return -EOPNOTSUPP;
if (kiocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
while (iov_iter_count(iter)) {
struct iovec iovec;
ssize_t nr;
if (!iov_iter_is_bvec(iter)) {
iovec = iov_iter_iovec(iter);
} else {
/* fixed buffers import bvec */
iovec.iov_base = kmap(iter->bvec->bv_page)
+ iter->iov_offset;
iovec.iov_len = min(iter->count,
iter->bvec->bv_len - iter->iov_offset);
}
if (rw == READ) {
nr = file->f_op->read(file, iovec.iov_base,
iovec.iov_len, &kiocb->ki_pos);
} else {
nr = file->f_op->write(file, iovec.iov_base,
iovec.iov_len, &kiocb->ki_pos);
}
if (iov_iter_is_bvec(iter))
kunmap(iter->bvec->bv_page);
if (nr < 0) {
if (!ret)
ret = nr;
break;
}
ret += nr;
if (nr != iovec.iov_len)
break;
iov_iter_advance(iter, nr);
}
return ret;
}
static void io_req_map_rw(struct io_kiocb *req, ssize_t io_size,
struct iovec *iovec, struct iovec *fast_iov,
struct iov_iter *iter)
{
req->io->rw.nr_segs = iter->nr_segs;
req->io->rw.size = io_size;
req->io->rw.iov = iovec;
if (!req->io->rw.iov) {
req->io->rw.iov = req->io->rw.fast_iov;
memcpy(req->io->rw.iov, fast_iov,
sizeof(struct iovec) * iter->nr_segs);
}
}
static int io_alloc_async_ctx(struct io_kiocb *req)
{
req->io = kmalloc(sizeof(*req->io), GFP_KERNEL);
return req->io == NULL;
}
static void io_rw_async(struct io_wq_work **workptr)
{
struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
struct iovec *iov = NULL;
if (req->io->rw.iov != req->io->rw.fast_iov)
iov = req->io->rw.iov;
io_wq_submit_work(workptr);
kfree(iov);
}
static int io_setup_async_rw(struct io_kiocb *req, ssize_t io_size,
struct iovec *iovec, struct iovec *fast_iov,
struct iov_iter *iter)
{
if (!req->io && io_alloc_async_ctx(req))
return -ENOMEM;
io_req_map_rw(req, io_size, iovec, fast_iov, iter);
req->work.func = io_rw_async;
return 0;
}
static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
bool force_nonblock)
{
struct io_async_ctx *io;
struct iov_iter iter;
ssize_t ret;
ret = io_prep_rw(req, sqe, force_nonblock);
if (ret)
return ret;
if (unlikely(!(req->file->f_mode & FMODE_READ)))
return -EBADF;
if (!req->io)
return 0;
io = req->io;
io->rw.iov = io->rw.fast_iov;
req->io = NULL;
ret = io_import_iovec(READ, req, &io->rw.iov, &iter);
req->io = io;
if (ret < 0)
return ret;
io_req_map_rw(req, ret, io->rw.iov, io->rw.fast_iov, &iter);
return 0;
}
static int io_read(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw.kiocb;
struct iov_iter iter;
size_t iov_count;
ssize_t io_size, ret;
ret = io_import_iovec(READ, req, &iovec, &iter);
if (ret < 0)
return ret;
/* Ensure we clear previously set non-block flag */
if (!force_nonblock)
req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;
io_size = ret;
if (req->flags & REQ_F_LINK)
req->result = io_size;
/*
* If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
* we know to async punt it even if it was opened O_NONBLOCK
*/
if (force_nonblock && !io_file_supports_async(req->file)) {
req->flags |= REQ_F_MUST_PUNT;
goto copy_iov;
}
iov_count = iov_iter_count(&iter);
ret = rw_verify_area(READ, req->file, &kiocb->ki_pos, iov_count);
if (!ret) {
ssize_t ret2;
if (req->file->f_op->read_iter)
ret2 = call_read_iter(req->file, kiocb, &iter);
else
ret2 = loop_rw_iter(READ, req->file, kiocb, &iter);
/* Catch -EAGAIN return for forced non-blocking submission */
if (!force_nonblock || ret2 != -EAGAIN) {
kiocb_done(kiocb, ret2, nxt, req->in_async);
} else {
copy_iov:
ret = io_setup_async_rw(req, io_size, iovec,
inline_vecs, &iter);
if (ret)
goto out_free;
return -EAGAIN;
}
}
out_free:
if (!io_wq_current_is_worker())
kfree(iovec);
return ret;
}
static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
bool force_nonblock)
{
struct io_async_ctx *io;
struct iov_iter iter;
ssize_t ret;
ret = io_prep_rw(req, sqe, force_nonblock);
if (ret)
return ret;
if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
return -EBADF;
if (!req->io)
return 0;
io = req->io;
io->rw.iov = io->rw.fast_iov;
req->io = NULL;
ret = io_import_iovec(WRITE, req, &io->rw.iov, &iter);
req->io = io;
if (ret < 0)
return ret;
io_req_map_rw(req, ret, io->rw.iov, io->rw.fast_iov, &iter);
return 0;
}
static int io_write(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw.kiocb;
struct iov_iter iter;
size_t iov_count;
ssize_t ret, io_size;
ret = io_import_iovec(WRITE, req, &iovec, &iter);
if (ret < 0)
return ret;
/* Ensure we clear previously set non-block flag */
if (!force_nonblock)
req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT;
io_size = ret;
if (req->flags & REQ_F_LINK)
req->result = io_size;
/*
* If the file doesn't support async, mark it as REQ_F_MUST_PUNT so
* we know to async punt it even if it was opened O_NONBLOCK
*/
if (force_nonblock && !io_file_supports_async(req->file)) {
req->flags |= REQ_F_MUST_PUNT;
goto copy_iov;
}
/* file path doesn't support NOWAIT for non-direct_IO */
if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
(req->flags & REQ_F_ISREG))
goto copy_iov;
iov_count = iov_iter_count(&iter);
ret = rw_verify_area(WRITE, req->file, &kiocb->ki_pos, iov_count);
if (!ret) {
ssize_t ret2;
/*
* Open-code file_start_write here to grab freeze protection,
* which will be released by another thread in
* io_complete_rw(). Fool lockdep by telling it the lock got
* released so that it doesn't complain about the held lock when
* we return to userspace.
*/
if (req->flags & REQ_F_ISREG) {
__sb_start_write(file_inode(req->file)->i_sb,
SB_FREEZE_WRITE, true);
__sb_writers_release(file_inode(req->file)->i_sb,
SB_FREEZE_WRITE);
}
kiocb->ki_flags |= IOCB_WRITE;
if (req->file->f_op->write_iter)
ret2 = call_write_iter(req->file, kiocb, &iter);
else
ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter);
if (!force_nonblock || ret2 != -EAGAIN) {
kiocb_done(kiocb, ret2, nxt, req->in_async);
} else {
copy_iov:
ret = io_setup_async_rw(req, io_size, iovec,
inline_vecs, &iter);
if (ret)
goto out_free;
return -EAGAIN;
}
}
out_free:
if (!io_wq_current_is_worker())
kfree(iovec);
return ret;
}
/*
* IORING_OP_NOP just posts a completion event, nothing else.
*/
static int io_nop(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
io_cqring_add_event(req, 0);
io_put_req(req);
return 0;
}
static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
if (!req->file)
return -EBADF;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
return -EINVAL;
req->sync.flags = READ_ONCE(sqe->fsync_flags);
if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC))
return -EINVAL;
req->sync.off = READ_ONCE(sqe->off);
req->sync.len = READ_ONCE(sqe->len);
return 0;
}
static bool io_req_cancelled(struct io_kiocb *req)
{
if (req->work.flags & IO_WQ_WORK_CANCEL) {
req_set_fail_links(req);
io_cqring_add_event(req, -ECANCELED);
io_put_req(req);
return true;
}
return false;
}
static void io_fsync_finish(struct io_wq_work **workptr)
{
struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
loff_t end = req->sync.off + req->sync.len;
struct io_kiocb *nxt = NULL;
int ret;
if (io_req_cancelled(req))
return;
ret = vfs_fsync_range(req->file, req->sync.off,
end > 0 ? end : LLONG_MAX,
req->sync.flags & IORING_FSYNC_DATASYNC);
if (ret < 0)
req_set_fail_links(req);
io_cqring_add_event(req, ret);
io_put_req_find_next(req, &nxt);
if (nxt)
*workptr = &nxt->work;
}
static int io_fsync(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
struct io_wq_work *work, *old_work;
/* fsync always requires a blocking context */
if (force_nonblock) {
io_put_req(req);
req->work.func = io_fsync_finish;
return -EAGAIN;
}
work = old_work = &req->work;
io_fsync_finish(&work);
if (work && work != old_work)
*nxt = container_of(work, struct io_kiocb, work);
return 0;
}
static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
if (!req->file)
return -EBADF;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
return -EINVAL;
req->sync.off = READ_ONCE(sqe->off);
req->sync.len = READ_ONCE(sqe->len);
req->sync.flags = READ_ONCE(sqe->sync_range_flags);
return 0;
}
static void io_sync_file_range_finish(struct io_wq_work **workptr)
{
struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
struct io_kiocb *nxt = NULL;
int ret;
if (io_req_cancelled(req))
return;
ret = sync_file_range(req->file, req->sync.off, req->sync.len,
req->sync.flags);
if (ret < 0)
req_set_fail_links(req);
io_cqring_add_event(req, ret);
io_put_req_find_next(req, &nxt);
if (nxt)
*workptr = &nxt->work;
}
static int io_sync_file_range(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
struct io_wq_work *work, *old_work;
/* sync_file_range always requires a blocking context */
if (force_nonblock) {
io_put_req(req);
req->work.func = io_sync_file_range_finish;
return -EAGAIN;
}
work = old_work = &req->work;
io_sync_file_range_finish(&work);
if (work && work != old_work)
*nxt = container_of(work, struct io_kiocb, work);
return 0;
}
#if defined(CONFIG_NET)
static void io_sendrecv_async(struct io_wq_work **workptr)
{
struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
struct iovec *iov = NULL;
if (req->io->rw.iov != req->io->rw.fast_iov)
iov = req->io->msg.iov;
io_wq_submit_work(workptr);
kfree(iov);
}
#endif
static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_NET)
struct io_sr_msg *sr = &req->sr_msg;
struct io_async_ctx *io = req->io;
sr->msg_flags = READ_ONCE(sqe->msg_flags);
sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr));
if (!io)
return 0;
io->msg.iov = io->msg.fast_iov;
return sendmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags,
&io->msg.iov);
#else
return -EOPNOTSUPP;
#endif
}
static int io_sendmsg(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
#if defined(CONFIG_NET)
struct io_async_msghdr *kmsg = NULL;
struct socket *sock;
int ret;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
sock = sock_from_file(req->file, &ret);
if (sock) {
struct io_async_ctx io;
struct sockaddr_storage addr;
unsigned flags;
if (req->io) {
kmsg = &req->io->msg;
kmsg->msg.msg_name = &addr;
/* if iov is set, it's allocated already */
if (!kmsg->iov)
kmsg->iov = kmsg->fast_iov;
kmsg->msg.msg_iter.iov = kmsg->iov;
} else {
struct io_sr_msg *sr = &req->sr_msg;
kmsg = &io.msg;
kmsg->msg.msg_name = &addr;
io.msg.iov = io.msg.fast_iov;
ret = sendmsg_copy_msghdr(&io.msg.msg, sr->msg,
sr->msg_flags, &io.msg.iov);
if (ret)
return ret;
}
flags = req->sr_msg.msg_flags;
if (flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
else if (force_nonblock)
flags |= MSG_DONTWAIT;
ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
if (force_nonblock && ret == -EAGAIN) {
if (req->io)
return -EAGAIN;
if (io_alloc_async_ctx(req))
return -ENOMEM;
memcpy(&req->io->msg, &io.msg, sizeof(io.msg));
req->work.func = io_sendrecv_async;
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
}
if (!io_wq_current_is_worker() && kmsg && kmsg->iov != kmsg->fast_iov)
kfree(kmsg->iov);
io_cqring_add_event(req, ret);
if (ret < 0)
req_set_fail_links(req);
io_put_req_find_next(req, nxt);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static int io_recvmsg_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_NET)
struct io_sr_msg *sr = &req->sr_msg;
struct io_async_ctx *io = req->io;
sr->msg_flags = READ_ONCE(sqe->msg_flags);
sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr));
if (!io)
return 0;
io->msg.iov = io->msg.fast_iov;
return recvmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags,
&io->msg.uaddr, &io->msg.iov);
#else
return -EOPNOTSUPP;
#endif
}
static int io_recvmsg(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
#if defined(CONFIG_NET)
struct io_async_msghdr *kmsg = NULL;
struct socket *sock;
int ret;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
sock = sock_from_file(req->file, &ret);
if (sock) {
struct io_async_ctx io;
struct sockaddr_storage addr;
unsigned flags;
if (req->io) {
kmsg = &req->io->msg;
kmsg->msg.msg_name = &addr;
/* if iov is set, it's allocated already */
if (!kmsg->iov)
kmsg->iov = kmsg->fast_iov;
kmsg->msg.msg_iter.iov = kmsg->iov;
} else {
struct io_sr_msg *sr = &req->sr_msg;
kmsg = &io.msg;
kmsg->msg.msg_name = &addr;
io.msg.iov = io.msg.fast_iov;
ret = recvmsg_copy_msghdr(&io.msg.msg, sr->msg,
sr->msg_flags, &io.msg.uaddr,
&io.msg.iov);
if (ret)
return ret;
}
flags = req->sr_msg.msg_flags;
if (flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
else if (force_nonblock)
flags |= MSG_DONTWAIT;
ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.msg,
kmsg->uaddr, flags);
if (force_nonblock && ret == -EAGAIN) {
if (req->io)
return -EAGAIN;
if (io_alloc_async_ctx(req))
return -ENOMEM;
memcpy(&req->io->msg, &io.msg, sizeof(io.msg));
req->work.func = io_sendrecv_async;
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
}
if (!io_wq_current_is_worker() && kmsg && kmsg->iov != kmsg->fast_iov)
kfree(kmsg->iov);
io_cqring_add_event(req, ret);
if (ret < 0)
req_set_fail_links(req);
io_put_req_find_next(req, nxt);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_NET)
struct io_accept *accept = &req->accept;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
return -EINVAL;
if (sqe->ioprio || sqe->len || sqe->buf_index)
return -EINVAL;
accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
accept->flags = READ_ONCE(sqe->accept_flags);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
#if defined(CONFIG_NET)
static int __io_accept(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
struct io_accept *accept = &req->accept;
unsigned file_flags;
int ret;
file_flags = force_nonblock ? O_NONBLOCK : 0;
ret = __sys_accept4_file(req->file, file_flags, accept->addr,
accept->addr_len, accept->flags);
if (ret == -EAGAIN && force_nonblock)
return -EAGAIN;
if (ret == -ERESTARTSYS)
ret = -EINTR;
if (ret < 0)
req_set_fail_links(req);
io_cqring_add_event(req, ret);
io_put_req_find_next(req, nxt);
return 0;
}
static void io_accept_finish(struct io_wq_work **workptr)
{
struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work);
struct io_kiocb *nxt = NULL;
if (io_req_cancelled(req))
return;
__io_accept(req, &nxt, false);
if (nxt)
*workptr = &nxt->work;
}
#endif
static int io_accept(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
#if defined(CONFIG_NET)
int ret;
ret = __io_accept(req, nxt, force_nonblock);
if (ret == -EAGAIN && force_nonblock) {
req->work.func = io_accept_finish;
req->work.flags |= IO_WQ_WORK_NEEDS_FILES;
io_put_req(req);
return -EAGAIN;
}
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_NET)
struct io_connect *conn = &req->connect;
struct io_async_ctx *io = req->io;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
return -EINVAL;
if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags)
return -EINVAL;
conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
conn->addr_len = READ_ONCE(sqe->addr2);
if (!io)
return 0;
return move_addr_to_kernel(conn->addr, conn->addr_len,
&io->connect.address);
#else
return -EOPNOTSUPP;
#endif
}
static int io_connect(struct io_kiocb *req, struct io_kiocb **nxt,
bool force_nonblock)
{
#if defined(CONFIG_NET)
struct io_async_ctx __io, *io;
unsigned file_flags;
int ret;
if (req->io) {
io = req->io;
} else {
ret = move_addr_to_kernel(req->connect.addr,
req->connect.addr_len,
&__io.connect.address);
if (ret)
goto out;
io = &__io;
}
file_flags = force_nonblock ? O_NONBLOCK : 0;
ret = __sys_connect_file(req->file, &io->connect.address,
req->connect.addr_len, file_flags);
if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
if (req->io)
return -EAGAIN;
if (io_alloc_async_ctx(req)) {
ret = -ENOMEM;
goto out;
}
memcpy(&req->io->connect, &__io.connect, sizeof(__io.connect));
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
out:
if (ret < 0)
req_set_fail_links(req);
io_cqring_add_event(req, ret);
io_put_req_find_next(req, nxt);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static void io_poll_remove_one(struct io_kiocb *req)
{
struct io_poll_iocb *poll = &req->poll;
spin_lock(&poll->head->lock);
WRITE_ONCE(poll->canceled, true);
if (!list_empty(&poll->wait.entry)) {
list_del_init(&poll->wait.entry);
io_queue_async_work(req);
}
spin_unlock(&poll->head->lock);
hash_del(&req->hash_node);
}
static void io_poll_remove_all(struct io_ring_ctx *ctx)
{
struct hlist_node *tmp;
struct io_kiocb *req;
int i;
spin_lock_irq(&ctx->completion_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
struct hlist_head *list;
list = &ctx->cancel_hash[i];
hlist_for_each_entry_safe(req, tmp, list, hash_node)
io_poll_remove_one(req);
}
spin_unlock_irq(&ctx->completion_lock);
}
static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr)
{
struct hlist_head *list;
struct io_kiocb *req;
list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)];
hlist_for_each_entry(req, list, hash_node) {
if (sqe_addr == req->user_data) {
io_poll_remove_one(req);
return 0;
}
}
return -ENOENT;
}
static int io_poll_remove_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
sqe->poll_events)
return -EINVAL;
req->poll.addr = READ_ONCE(sqe->addr);
return 0;
}
/*
* Find a running poll command that matches one specified in sqe->addr,
* and remove it if found.
*/
static int io_poll_remove(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
u64 addr;
int ret;
addr = req->poll.addr;
spin_lock_irq(&ctx->completion_lock);
ret = io_poll_cancel(ctx, addr);
spin_unlock_irq(&ctx->completion_lock);
io_cqring_add_event(req, ret);
if (ret < 0)
req_set_fail_links(req);
io_put_req(req);
return 0;
}
static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
{
struct io_ring_ctx *ctx = req->ctx;
req->poll.done = true;
if (error)
io_cqring_fill_event(req, error);
else
io_cqring_fill_event(req, mangle_poll(mask));
io_commit_cqring(ctx);
}
static void io_poll_complete_work(struct io_wq_work **workptr)
{
struct io_wq_work *work = *workptr;
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_poll_iocb *poll = &req->poll;
struct poll_table_struct pt = { ._key = poll->events };
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *nxt = NULL;
__poll_t mask = 0;
int ret = 0;
if (work->flags & IO_WQ_WORK_CANCEL) {
WRITE_ONCE(poll->canceled, true);
ret = -ECANCELED;
} else if (READ_ONCE(poll->canceled)) {
ret = -ECANCELED;
}
if (ret != -ECANCELED)
mask = vfs_poll(poll->file, &pt) & poll->events;
/*
* Note that ->ki_cancel callers also delete iocb from active_reqs after
* calling ->ki_cancel. We need the ctx_lock roundtrip here to
* synchronize with them. In the cancellation case the list_del_init
* itself is not actually needed, but harmless so we keep it in to
* avoid further branches in the fast path.
*/
spin_lock_irq(&ctx->completion_lock);
if (!mask && ret != -ECANCELED) {
add_wait_queue(poll->head, &poll->wait);
spin_unlock_irq(&ctx->completion_lock);
return;
}
hash_del(&req->hash_node);
io_poll_complete(req, mask, ret);
spin_unlock_irq(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
if (ret < 0)
req_set_fail_links(req);
io_put_req_find_next(req, &nxt);
if (nxt)
*workptr = &nxt->work;
}
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
void *key)
{
struct io_poll_iocb *poll = wait->private;
struct io_kiocb *req = container_of(poll, struct io_kiocb, poll);
struct io_ring_ctx *ctx = req->ctx;
__poll_t mask = key_to_poll(key);
unsigned long flags;
/* for instances that support it check for an event match first: */
if (mask && !(mask & poll->events))
return 0;
list_del_init(&poll->wait.entry);
/*
* Run completion inline if we can. We're using trylock here because
* we are violating the completion_lock -> poll wq lock ordering.
* If we have a link timeout we're going to need the completion_lock
* for finalizing the request, mark us as having grabbed that already.
*/
if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) {
hash_del(&req->hash_node);
io_poll_complete(req, mask, 0);
req->flags |= REQ_F_COMP_LOCKED;
io_put_req(req);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
} else {
io_queue_async_work(req);
}
return 1;
}
struct io_poll_table {
struct poll_table_struct pt;
struct io_kiocb *req;
int error;
};
static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
struct poll_table_struct *p)
{
struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
if (unlikely(pt->req->poll.head)) {
pt->error = -EINVAL;
return;
}
pt->error = 0;
pt->req->poll.head = head;
add_wait_queue(head, &pt->req->poll.wait);
}
static void io_poll_req_insert(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct hlist_head *list;
list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
hlist_add_head(&req->hash_node, list);
}
static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_poll_iocb *poll = &req->poll;
u16 events;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
return -EINVAL;
if (!poll->file)
return -EBADF;
events = READ_ONCE(sqe->poll_events);
poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
return 0;
}
static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt)
{
struct io_poll_iocb *poll = &req->poll;
struct io_ring_ctx *ctx = req->ctx;
struct io_poll_table ipt;
bool cancel = false;
__poll_t mask;
INIT_IO_WORK(&req->work, io_poll_complete_work);
INIT_HLIST_NODE(&req->hash_node);
poll->head = NULL;
poll->done = false;
poll->canceled = false;
ipt.pt._qproc = io_poll_queue_proc;
ipt.pt._key = poll->events;
ipt.req = req;
ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
/* initialized the list so that we can do list_empty checks */
INIT_LIST_HEAD(&poll->wait.entry);
init_waitqueue_func_entry(&poll->wait, io_poll_wake);
poll->wait.private = poll;
INIT_LIST_HEAD(&req->list);
mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
spin_lock_irq(&ctx->completion_lock);
if (likely(poll->head)) {
spin_lock(&poll->head->lock);
if (unlikely(list_empty(&poll->wait.entry))) {
if (ipt.error)
cancel = true;
ipt.error = 0;
mask = 0;
}
if (mask || ipt.error)
list_del_init(&poll->wait.entry);
else if (cancel)
WRITE_ONCE(poll->canceled, true);
else if (!poll->done) /* actually waiting for an event */
io_poll_req_insert(req);
spin_unlock(&poll->head->lock);
}
if (mask) { /* no async, we'd stolen it */
ipt.error = 0;
io_poll_complete(req, mask, 0);
}
spin_unlock_irq(&ctx->completion_lock);
if (mask) {
io_cqring_ev_posted(ctx);
io_put_req_find_next(req, nxt);
}
return ipt.error;
}
static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
{
struct io_timeout_data *data = container_of(timer,
struct io_timeout_data, timer);
struct io_kiocb *req = data->req;
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
atomic_inc(&ctx->cq_timeouts);
spin_lock_irqsave(&ctx->completion_lock, flags);
/*
* We could be racing with timeout deletion. If the list is empty,
* then timeout lookup already found it and will be handling it.
*/
if (!list_empty(&req->list)) {
struct io_kiocb *prev;
/*
* Adjust the reqs sequence before the current one because it
* will consume a slot in the cq_ring and the cq_tail
* pointer will be increased, otherwise other timeout reqs may
* return in advance without waiting for enough wait_nr.
*/
prev = req;
list_for_each_entry_continue_reverse(prev, &ctx->timeout_list, list)
prev->sequence++;
list_del_init(&req->list);
}
io_cqring_fill_event(req, -ETIME);
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
req_set_fail_links(req);
io_put_req(req);
return HRTIMER_NORESTART;
}
static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
{
struct io_kiocb *req;
int ret = -ENOENT;
list_for_each_entry(req, &ctx->timeout_list, list) {
if (user_data == req->user_data) {
list_del_init(&req->list);
ret = 0;
break;
}
}
if (ret == -ENOENT)
return ret;
ret = hrtimer_try_to_cancel(&req->io->timeout.timer);
if (ret == -1)
return -EALREADY;
req_set_fail_links(req);
io_cqring_fill_event(req, -ECANCELED);
io_put_req(req);
return 0;
}
static int io_timeout_remove_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->flags || sqe->ioprio || sqe->buf_index || sqe->len)
return -EINVAL;
req->timeout.addr = READ_ONCE(sqe->addr);
req->timeout.flags = READ_ONCE(sqe->timeout_flags);
if (req->timeout.flags)
return -EINVAL;
return 0;
}
/*
* Remove or update an existing timeout command
*/
static int io_timeout_remove(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
spin_lock_irq(&ctx->completion_lock);
ret = io_timeout_cancel(ctx, req->timeout.addr);
io_cqring_fill_event(req, ret);
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
if (ret < 0)
req_set_fail_links(req);
io_put_req(req);
return 0;
}
static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
bool is_timeout_link)
{
struct io_timeout_data *data;
unsigned flags;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->ioprio || sqe->buf_index || sqe->len != 1)
return -EINVAL;
if (sqe->off && is_timeout_link)
return -EINVAL;
flags = READ_ONCE(sqe->timeout_flags);
if (flags & ~IORING_TIMEOUT_ABS)
return -EINVAL;
req->timeout.count = READ_ONCE(sqe->off);
if (!req->io && io_alloc_async_ctx(req))
return -ENOMEM;
data = &req->io->timeout;
data->req = req;
req->flags |= REQ_F_TIMEOUT;
if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
return -EFAULT;
if (flags & IORING_TIMEOUT_ABS)
data->mode = HRTIMER_MODE_ABS;
else
data->mode = HRTIMER_MODE_REL;
hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode);
return 0;
}
static int io_timeout(struct io_kiocb *req)
{
unsigned count;
struct io_ring_ctx *ctx = req->ctx;
struct io_timeout_data *data;
struct list_head *entry;
unsigned span = 0;
data = &req->io->timeout;
/*
* sqe->off holds how many events that need to occur for this
* timeout event to be satisfied. If it isn't set, then this is
* a pure timeout request, sequence isn't used.
*/
count = req->timeout.count;
if (!count) {
req->flags |= REQ_F_TIMEOUT_NOSEQ;
spin_lock_irq(&ctx->completion_lock);
entry = ctx->timeout_list.prev;
goto add;
}
req->sequence = ctx->cached_sq_head + count - 1;
data->seq_offset = count;
/*
* Insertion sort, ensuring the first entry in the list is always
* the one we need first.
*/
spin_lock_irq(&ctx->completion_lock);
list_for_each_prev(entry, &ctx->timeout_list) {
struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, list);
unsigned nxt_sq_head;
long long tmp, tmp_nxt;
u32 nxt_offset = nxt->io->timeout.seq_offset;
if (nxt->flags & REQ_F_TIMEOUT_NOSEQ)
continue;
/*
* Since cached_sq_head + count - 1 can overflow, use type long
* long to store it.
*/
tmp = (long long)ctx->cached_sq_head + count - 1;
nxt_sq_head = nxt->sequence - nxt_offset + 1;
tmp_nxt = (long long)nxt_sq_head + nxt_offset - 1;
/*
* cached_sq_head may overflow, and it will never overflow twice
* once there is some timeout req still be valid.
*/
if (ctx->cached_sq_head < nxt_sq_head)
tmp += UINT_MAX;
if (tmp > tmp_nxt)
break;
/*
* Sequence of reqs after the insert one and itself should
* be adjusted because each timeout req consumes a slot.
*/
span++;
nxt->sequence++;
}
req->sequence -= span;
add:
list_add(&req->list, entry);
data->timer.function = io_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
spin_unlock_irq(&ctx->completion_lock);
return 0;
}
static bool io_cancel_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
return req->user_data == (unsigned long) data;
}
static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr)
{
enum io_wq_cancel cancel_ret;
int ret = 0;
cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr);
switch (cancel_ret) {
case IO_WQ_CANCEL_OK:
ret = 0;
break;
case IO_WQ_CANCEL_RUNNING:
ret = -EALREADY;
break;
case IO_WQ_CANCEL_NOTFOUND:
ret = -ENOENT;
break;
}
return ret;
}
static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
struct io_kiocb *req, __u64 sqe_addr,
struct io_kiocb **nxt, int success_ret)
{
unsigned long flags;
int ret;
ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr);
if (ret != -ENOENT) {
spin_lock_irqsave(&ctx->completion_lock, flags);
goto done;
}
spin_lock_irqsave(&ctx->completion_lock, flags);
ret = io_timeout_cancel(ctx, sqe_addr);
if (ret != -ENOENT)
goto done;
ret = io_poll_cancel(ctx, sqe_addr);
done:
if (!ret)
ret = success_ret;
io_cqring_fill_event(req, ret);
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
if (ret < 0)
req_set_fail_links(req);
io_put_req_find_next(req, nxt);
}
static int io_async_cancel_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->flags || sqe->ioprio || sqe->off || sqe->len ||
sqe->cancel_flags)
return -EINVAL;
req->cancel.addr = READ_ONCE(sqe->addr);
return 0;
}
static int io_async_cancel(struct io_kiocb *req, struct io_kiocb **nxt)
{
struct io_ring_ctx *ctx = req->ctx;
io_async_find_and_cancel(ctx, req, req->cancel.addr, nxt, 0);
return 0;
}
static int io_req_defer_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
ssize_t ret = 0;
switch (req->opcode) {
case IORING_OP_NOP:
break;
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
ret = io_read_prep(req, sqe, true);
break;
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
ret = io_write_prep(req, sqe, true);
break;
case IORING_OP_POLL_ADD:
ret = io_poll_add_prep(req, sqe);
break;
case IORING_OP_POLL_REMOVE:
ret = io_poll_remove_prep(req, sqe);
break;
case IORING_OP_FSYNC:
ret = io_prep_fsync(req, sqe);
break;
case IORING_OP_SYNC_FILE_RANGE:
ret = io_prep_sfr(req, sqe);
break;
case IORING_OP_SENDMSG:
ret = io_sendmsg_prep(req, sqe);
break;
case IORING_OP_RECVMSG:
ret = io_recvmsg_prep(req, sqe);
break;
case IORING_OP_CONNECT:
ret = io_connect_prep(req, sqe);
break;
case IORING_OP_TIMEOUT:
ret = io_timeout_prep(req, sqe, false);
break;
case IORING_OP_TIMEOUT_REMOVE:
ret = io_timeout_remove_prep(req, sqe);
break;
case IORING_OP_ASYNC_CANCEL:
ret = io_async_cancel_prep(req, sqe);
break;
case IORING_OP_LINK_TIMEOUT:
ret = io_timeout_prep(req, sqe, true);
break;
case IORING_OP_ACCEPT:
ret = io_accept_prep(req, sqe);
break;
default:
printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
req->opcode);
ret = -EINVAL;
break;
}
return ret;
}
static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
/* Still need defer if there is pending req in defer list. */
if (!req_need_defer(req) && list_empty(&ctx->defer_list))
return 0;
if (!req->io && io_alloc_async_ctx(req))
return -EAGAIN;
ret = io_req_defer_prep(req, sqe);
if (ret < 0)
return ret;
spin_lock_irq(&ctx->completion_lock);
if (!req_need_defer(req) && list_empty(&ctx->defer_list)) {
spin_unlock_irq(&ctx->completion_lock);
return 0;
}
trace_io_uring_defer(ctx, req, req->user_data);
list_add_tail(&req->list, &ctx->defer_list);
spin_unlock_irq(&ctx->completion_lock);
return -EIOCBQUEUED;
}
static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
struct io_kiocb **nxt, bool force_nonblock)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
switch (req->opcode) {
case IORING_OP_NOP:
ret = io_nop(req);
break;
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
if (sqe) {
ret = io_read_prep(req, sqe, force_nonblock);
if (ret < 0)
break;
}
ret = io_read(req, nxt, force_nonblock);
break;
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
if (sqe) {
ret = io_write_prep(req, sqe, force_nonblock);
if (ret < 0)
break;
}
ret = io_write(req, nxt, force_nonblock);
break;
case IORING_OP_FSYNC:
if (sqe) {
ret = io_prep_fsync(req, sqe);
if (ret < 0)
break;
}
ret = io_fsync(req, nxt, force_nonblock);
break;
case IORING_OP_POLL_ADD:
if (sqe) {
ret = io_poll_add_prep(req, sqe);
if (ret)
break;
}
ret = io_poll_add(req, nxt);
break;
case IORING_OP_POLL_REMOVE:
if (sqe) {
ret = io_poll_remove_prep(req, sqe);
if (ret < 0)
break;
}
ret = io_poll_remove(req);
break;
case IORING_OP_SYNC_FILE_RANGE:
if (sqe) {
ret = io_prep_sfr(req, sqe);
if (ret < 0)
break;
}
ret = io_sync_file_range(req, nxt, force_nonblock);
break;
case IORING_OP_SENDMSG:
if (sqe) {
ret = io_sendmsg_prep(req, sqe);
if (ret < 0)
break;
}
ret = io_sendmsg(req, nxt, force_nonblock);
break;
case IORING_OP_RECVMSG:
if (sqe) {
ret = io_recvmsg_prep(req, sqe);
if (ret)
break;
}
ret = io_recvmsg(req, nxt, force_nonblock);
break;
case IORING_OP_TIMEOUT:
if (sqe) {
ret = io_timeout_prep(req, sqe, false);
if (ret)
break;
}
ret = io_timeout(req);
break;
case IORING_OP_TIMEOUT_REMOVE:
if (sqe) {
ret = io_timeout_remove_prep(req, sqe);
if (ret)
break;
}
ret = io_timeout_remove(req);
break;
case IORING_OP_ACCEPT:
if (sqe) {
ret = io_accept_prep(req, sqe);
if (ret)
break;
}
ret = io_accept(req, nxt, force_nonblock);
break;
case IORING_OP_CONNECT:
if (sqe) {
ret = io_connect_prep(req, sqe);
if (ret)
break;
}
ret = io_connect(req, nxt, force_nonblock);
break;
case IORING_OP_ASYNC_CANCEL:
if (sqe) {
ret = io_async_cancel_prep(req, sqe);
if (ret)
break;
}
ret = io_async_cancel(req, nxt);
break;
default:
ret = -EINVAL;
break;
}
if (ret)
return ret;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (req->result == -EAGAIN)
return -EAGAIN;
io_iopoll_req_issued(req);
}
return 0;
}
static void io_link_work_cb(struct io_wq_work **workptr)
{
struct io_wq_work *work = *workptr;
struct io_kiocb *link = work->data;
io_queue_linked_timeout(link);
work->func = io_wq_submit_work;
}
static void io_wq_submit_work(struct io_wq_work **workptr)
{
struct io_wq_work *work = *workptr;
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_kiocb *nxt = NULL;
int ret = 0;
if (work->flags & IO_WQ_WORK_CANCEL)
ret = -ECANCELED;
if (!ret) {
req->has_user = (work->flags & IO_WQ_WORK_HAS_MM) != 0;
req->in_async = true;
do {
ret = io_issue_sqe(req, NULL, &nxt, false);
/*
* We can get EAGAIN for polled IO even though we're
* forcing a sync submission from here, since we can't
* wait for request slots on the block side.
*/
if (ret != -EAGAIN)
break;
cond_resched();
} while (1);
}
/* drop submission reference */
io_put_req(req);
if (ret) {
req_set_fail_links(req);
io_cqring_add_event(req, ret);
io_put_req(req);
}
/* if a dependent link is ready, pass it back */
if (!ret && nxt) {
struct io_kiocb *link;
io_prep_async_work(nxt, &link);
*workptr = &nxt->work;
if (link) {
nxt->work.flags |= IO_WQ_WORK_CB;
nxt->work.func = io_link_work_cb;
nxt->work.data = link;
}
}
}
static bool io_req_op_valid(int op)
{
return op >= IORING_OP_NOP && op < IORING_OP_LAST;
}
static int io_req_needs_file(struct io_kiocb *req)
{
switch (req->opcode) {
case IORING_OP_NOP:
case IORING_OP_POLL_REMOVE:
case IORING_OP_TIMEOUT:
case IORING_OP_TIMEOUT_REMOVE:
case IORING_OP_ASYNC_CANCEL:
case IORING_OP_LINK_TIMEOUT:
return 0;
default:
if (io_req_op_valid(req->opcode))
return 1;
return -EINVAL;
}
}
static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
int index)
{
struct fixed_file_table *table;
table = &ctx->file_table[index >> IORING_FILE_TABLE_SHIFT];
return table->files[index & IORING_FILE_TABLE_MASK];
}
static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned flags;
int fd, ret;
flags = READ_ONCE(sqe->flags);
fd = READ_ONCE(sqe->fd);
if (flags & IOSQE_IO_DRAIN)
req->flags |= REQ_F_IO_DRAIN;
ret = io_req_needs_file(req);
if (ret <= 0)
return ret;
if (flags & IOSQE_FIXED_FILE) {
if (unlikely(!ctx->file_table ||
(unsigned) fd >= ctx->nr_user_files))
return -EBADF;
fd = array_index_nospec(fd, ctx->nr_user_files);
req->file = io_file_from_index(ctx, fd);
if (!req->file)
return -EBADF;
req->flags |= REQ_F_FIXED_FILE;
} else {
if (req->needs_fixed_file)
return -EBADF;
trace_io_uring_file_get(ctx, fd);
req->file = io_file_get(state, fd);
if (unlikely(!req->file))
return -EBADF;
}
return 0;
}
static int io_grab_files(struct io_kiocb *req)
{
int ret = -EBADF;
struct io_ring_ctx *ctx = req->ctx;
rcu_read_lock();
spin_lock_irq(&ctx->inflight_lock);
/*
* We use the f_ops->flush() handler to ensure that we can flush
* out work accessing these files if the fd is closed. Check if
* the fd has changed since we started down this path, and disallow
* this operation if it has.
*/
if (fcheck(req->ring_fd) == req->ring_file) {
list_add(&req->inflight_entry, &ctx->inflight_list);
req->flags |= REQ_F_INFLIGHT;
req->work.files = current->files;
ret = 0;
}
spin_unlock_irq(&ctx->inflight_lock);
rcu_read_unlock();
return ret;
}
static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
{
struct io_timeout_data *data = container_of(timer,
struct io_timeout_data, timer);
struct io_kiocb *req = data->req;
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *prev = NULL;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
/*
* We don't expect the list to be empty, that will only happen if we
* race with the completion of the linked work.
*/
if (!list_empty(&req->link_list)) {
prev = list_entry(req->link_list.prev, struct io_kiocb,
link_list);
if (refcount_inc_not_zero(&prev->refs)) {
list_del_init(&req->link_list);
prev->flags &= ~REQ_F_LINK_TIMEOUT;
} else
prev = NULL;
}
spin_unlock_irqrestore(&ctx->completion_lock, flags);
if (prev) {
req_set_fail_links(prev);
io_async_find_and_cancel(ctx, req, prev->user_data, NULL,
-ETIME);
io_put_req(prev);
} else {
io_cqring_add_event(req, -ETIME);
io_put_req(req);
}
return HRTIMER_NORESTART;
}
static void io_queue_linked_timeout(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
/*
* If the list is now empty, then our linked request finished before
* we got a chance to setup the timer
*/
spin_lock_irq(&ctx->completion_lock);
if (!list_empty(&req->link_list)) {
struct io_timeout_data *data = &req->io->timeout;
data->timer.function = io_link_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
data->mode);
}
spin_unlock_irq(&ctx->completion_lock);
/* drop submission reference */
io_put_req(req);
}
static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
{
struct io_kiocb *nxt;
if (!(req->flags & REQ_F_LINK))
return NULL;
nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb,
link_list);
if (!nxt || nxt->opcode != IORING_OP_LINK_TIMEOUT)
return NULL;
req->flags |= REQ_F_LINK_TIMEOUT;
return nxt;
}
static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_kiocb *linked_timeout;
struct io_kiocb *nxt = NULL;
int ret;
again:
linked_timeout = io_prep_linked_timeout(req);
ret = io_issue_sqe(req, sqe, &nxt, true);
/*
* We async punt it if the file wasn't marked NOWAIT, or if the file
* doesn't support non-blocking read/write attempts
*/
if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) ||
(req->flags & REQ_F_MUST_PUNT))) {
if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) {
ret = io_grab_files(req);
if (ret)
goto err;
}
/*
* Queued up for async execution, worker will release
* submit reference when the iocb is actually submitted.
*/
io_queue_async_work(req);
goto done_req;
}
err:
/* drop submission reference */
io_put_req(req);
if (linked_timeout) {
if (!ret)
io_queue_linked_timeout(linked_timeout);
else
io_put_req(linked_timeout);
}
/* and drop final reference, if we failed */
if (ret) {
io_cqring_add_event(req, ret);
req_set_fail_links(req);
io_put_req(req);
}
done_req:
if (nxt) {
req = nxt;
nxt = NULL;
goto again;
}
}
static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
int ret;
if (unlikely(req->ctx->drain_next)) {
req->flags |= REQ_F_IO_DRAIN;
req->ctx->drain_next = false;
}
req->ctx->drain_next = (req->flags & REQ_F_DRAIN_LINK);
ret = io_req_defer(req, sqe);
if (ret) {
if (ret != -EIOCBQUEUED) {
io_cqring_add_event(req, ret);
req_set_fail_links(req);
io_double_put_req(req);
}
} else
__io_queue_sqe(req, sqe);
}
static inline void io_queue_link_head(struct io_kiocb *req)
{
if (unlikely(req->flags & REQ_F_FAIL_LINK)) {
io_cqring_add_event(req, -ECANCELED);
io_double_put_req(req);
} else
io_queue_sqe(req, NULL);
}
#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \
IOSQE_IO_HARDLINK)
static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
struct io_submit_state *state, struct io_kiocb **link)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
/* enforce forwards compatibility on users */
if (unlikely(sqe->flags & ~SQE_VALID_FLAGS)) {
ret = -EINVAL;
goto err_req;
}
ret = io_req_set_file(state, req, sqe);
if (unlikely(ret)) {
err_req:
io_cqring_add_event(req, ret);
io_double_put_req(req);
return false;
}
/*
* If we already have a head request, queue this one for async
* submittal once the head completes. If we don't have a head but
* IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
* submitted sync once the chain is complete. If none of those
* conditions are true (normal request), then just queue it.
*/
if (*link) {
struct io_kiocb *prev = *link;
if (sqe->flags & IOSQE_IO_DRAIN)
(*link)->flags |= REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN;
if (sqe->flags & IOSQE_IO_HARDLINK)
req->flags |= REQ_F_HARDLINK;
if (io_alloc_async_ctx(req)) {
ret = -EAGAIN;
goto err_req;
}
ret = io_req_defer_prep(req, sqe);
if (ret) {
/* fail even hard links since we don't submit */
prev->flags |= REQ_F_FAIL_LINK;
goto err_req;
}
trace_io_uring_link(ctx, req, prev);
list_add_tail(&req->link_list, &prev->link_list);
} else if (sqe->flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) {
req->flags |= REQ_F_LINK;
if (sqe->flags & IOSQE_IO_HARDLINK)
req->flags |= REQ_F_HARDLINK;
INIT_LIST_HEAD(&req->link_list);
ret = io_req_defer_prep(req, sqe);
if (ret)
req->flags |= REQ_F_FAIL_LINK;
*link = req;
} else {
io_queue_sqe(req, sqe);
}
return true;
}
/*
* Batched submission is done, ensure local IO is flushed out.
*/
static void io_submit_state_end(struct io_submit_state *state)
{
blk_finish_plug(&state->plug);
io_file_put(state);
if (state->free_reqs)
kmem_cache_free_bulk(req_cachep, state->free_reqs,
&state->reqs[state->cur_req]);
}
/*
* Start submission side cache.
*/
static void io_submit_state_start(struct io_submit_state *state,
unsigned int max_ios)
{
blk_start_plug(&state->plug);
state->free_reqs = 0;
state->file = NULL;
state->ios_left = max_ios;
}
static void io_commit_sqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) {
/*
* Ensure any loads from the SQEs are done at this point,
* since once we write the new head, the application could
* write new data to them.
*/
smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}
}
/*
* Fetch an sqe, if one is available. Note that sqe_ptr will point to memory
* that is mapped by userspace. This means that care needs to be taken to
* ensure that reads are stable, as we cannot rely on userspace always
* being a good citizen. If members of the sqe are validated and then later
* used, it's important that those reads are done through READ_ONCE() to
* prevent a re-load down the line.
*/
static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe **sqe_ptr)
{
struct io_rings *rings = ctx->rings;
u32 *sq_array = ctx->sq_array;
unsigned head;
/*
* The cached sq head (or cq tail) serves two purposes:
*
* 1) allows us to batch the cost of updating the user visible
* head updates.
* 2) allows the kernel side to track the head on its own, even
* though the application is the one updating it.
*/
head = ctx->cached_sq_head;
/* make sure SQ entry isn't read before tail */
if (unlikely(head == smp_load_acquire(&rings->sq.tail)))
return false;
head = READ_ONCE(sq_array[head & ctx->sq_mask]);
if (likely(head < ctx->sq_entries)) {
/*
* All io need record the previous position, if LINK vs DARIN,
* it can be used to mark the position of the first IO in the
* link list.
*/
req->sequence = ctx->cached_sq_head;
*sqe_ptr = &ctx->sq_sqes[head];
req->opcode = READ_ONCE((*sqe_ptr)->opcode);
req->user_data = READ_ONCE((*sqe_ptr)->user_data);
ctx->cached_sq_head++;
return true;
}
/* drop invalid entries */
ctx->cached_sq_head++;
ctx->cached_sq_dropped++;
WRITE_ONCE(rings->sq_dropped, ctx->cached_sq_dropped);
return false;
}
static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr,
struct file *ring_file, int ring_fd,
struct mm_struct **mm, bool async)
{
struct io_submit_state state, *statep = NULL;
struct io_kiocb *link = NULL;
int i, submitted = 0;
bool mm_fault = false;
/* if we have a backlog and couldn't flush it all, return BUSY */
if (!list_empty(&ctx->cq_overflow_list) &&
!io_cqring_overflow_flush(ctx, false))
return -EBUSY;
if (nr > IO_PLUG_THRESHOLD) {
io_submit_state_start(&state, nr);
statep = &state;
}
for (i = 0; i < nr; i++) {
const struct io_uring_sqe *sqe;
struct io_kiocb *req;
unsigned int sqe_flags;
req = io_get_req(ctx, statep);
if (unlikely(!req)) {
if (!submitted)
submitted = -EAGAIN;
break;
}
if (!io_get_sqring(ctx, req, &sqe)) {
__io_free_req(req);
break;
}
if (io_req_needs_user(req) && !*mm) {
mm_fault = mm_fault || !mmget_not_zero(ctx->sqo_mm);
if (!mm_fault) {
use_mm(ctx->sqo_mm);
*mm = ctx->sqo_mm;
}
}
submitted++;
sqe_flags = sqe->flags;
req->ring_file = ring_file;
req->ring_fd = ring_fd;
req->has_user = *mm != NULL;
req->in_async = async;
req->needs_fixed_file = async;
trace_io_uring_submit_sqe(ctx, req->user_data, true, async);
if (!io_submit_sqe(req, sqe, statep, &link))
break;
/*
* If previous wasn't linked and we have a linked command,
* that's the end of the chain. Submit the previous link.
*/
if (!(sqe_flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) && link) {
io_queue_link_head(link);
link = NULL;
}
}
if (link)
io_queue_link_head(link);
if (statep)
io_submit_state_end(&state);
/* Commit SQ ring head once we've consumed and submitted all SQEs */
io_commit_sqring(ctx);
return submitted;
}
static int io_sq_thread(void *data)
{
struct io_ring_ctx *ctx = data;
struct mm_struct *cur_mm = NULL;
const struct cred *old_cred;
mm_segment_t old_fs;
DEFINE_WAIT(wait);
unsigned inflight;
unsigned long timeout;
int ret;
complete(&ctx->completions[1]);
old_fs = get_fs();
set_fs(USER_DS);
old_cred = override_creds(ctx->creds);
ret = timeout = inflight = 0;
while (!kthread_should_park()) {
unsigned int to_submit;
if (inflight) {
unsigned nr_events = 0;
if (ctx->flags & IORING_SETUP_IOPOLL) {
/*
* inflight is the count of the maximum possible
* entries we submitted, but it can be smaller
* if we dropped some of them. If we don't have
* poll entries available, then we know that we
* have nothing left to poll for. Reset the
* inflight count to zero in that case.
*/
mutex_lock(&ctx->uring_lock);
if (!list_empty(&ctx->poll_list))
__io_iopoll_check(ctx, &nr_events, 0);
else
inflight = 0;
mutex_unlock(&ctx->uring_lock);
} else {
/*
* Normal IO, just pretend everything completed.
* We don't have to poll completions for that.
*/
nr_events = inflight;
}
inflight -= nr_events;
if (!inflight)
timeout = jiffies + ctx->sq_thread_idle;
}
to_submit = io_sqring_entries(ctx);
/*
* If submit got -EBUSY, flag us as needing the application
* to enter the kernel to reap and flush events.
*/
if (!to_submit || ret == -EBUSY) {
/*
* We're polling. If we're within the defined idle
* period, then let us spin without work before going
* to sleep. The exception is if we got EBUSY doing
* more IO, we should wait for the application to
* reap events and wake us up.
*/
if (inflight ||
(!time_after(jiffies, timeout) && ret != -EBUSY)) {
cond_resched();
continue;
}
/*
* Drop cur_mm before scheduling, we can't hold it for
* long periods (or over schedule()). Do this before
* adding ourselves to the waitqueue, as the unuse/drop
* may sleep.
*/
if (cur_mm) {
unuse_mm(cur_mm);
mmput(cur_mm);
cur_mm = NULL;
}
prepare_to_wait(&ctx->sqo_wait, &wait,
TASK_INTERRUPTIBLE);
/* Tell userspace we may need a wakeup call */
ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
/* make sure to read SQ tail after writing flags */
smp_mb();
to_submit = io_sqring_entries(ctx);
if (!to_submit || ret == -EBUSY) {
if (kthread_should_park()) {
finish_wait(&ctx->sqo_wait, &wait);
break;
}
if (signal_pending(current))
flush_signals(current);
schedule();
finish_wait(&ctx->sqo_wait, &wait);
ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
continue;
}
finish_wait(&ctx->sqo_wait, &wait);
ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
}
to_submit = min(to_submit, ctx->sq_entries);
mutex_lock(&ctx->uring_lock);
ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true);
mutex_unlock(&ctx->uring_lock);
if (ret > 0)
inflight += ret;
}
set_fs(old_fs);
if (cur_mm) {
unuse_mm(cur_mm);
mmput(cur_mm);
}
revert_creds(old_cred);
kthread_parkme();
return 0;
}
struct io_wait_queue {
struct wait_queue_entry wq;
struct io_ring_ctx *ctx;
unsigned to_wait;
unsigned nr_timeouts;
};
static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush)
{
struct io_ring_ctx *ctx = iowq->ctx;
/*
* Wake up if we have enough events, or if a timeout occurred since we
* started waiting. For timeouts, we always want to return to userspace,
* regardless of event count.
*/
return io_cqring_events(ctx, noflush) >= iowq->to_wait ||
atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
}
static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
int wake_flags, void *key)
{
struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
wq);
/* use noflush == true, as we can't safely rely on locking context */
if (!io_should_wake(iowq, true))
return -1;
return autoremove_wake_function(curr, mode, wake_flags, key);
}
/*
* Wait until events become available, if we don't already have some. The
* application must reap them itself, as they reside on the shared cq ring.
*/
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
const sigset_t __user *sig, size_t sigsz)
{
struct io_wait_queue iowq = {
.wq = {
.private = current,
.func = io_wake_function,
.entry = LIST_HEAD_INIT(iowq.wq.entry),
},
.ctx = ctx,
.to_wait = min_events,
};
struct io_rings *rings = ctx->rings;
int ret = 0;
if (io_cqring_events(ctx, false) >= min_events)
return 0;
if (sig) {
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
sigsz);
else
#endif
ret = set_user_sigmask(sig, sigsz);
if (ret)
return ret;
}
iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
trace_io_uring_cqring_wait(ctx, min_events);
do {
prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
TASK_INTERRUPTIBLE);
if (io_should_wake(&iowq, false))
break;
schedule();
if (signal_pending(current)) {
ret = -EINTR;
break;
}
} while (1);
finish_wait(&ctx->wait, &iowq.wq);
restore_saved_sigmask_unless(ret == -EINTR);
return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}
static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
#if defined(CONFIG_UNIX)
if (ctx->ring_sock) {
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff *skb;
while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
kfree_skb(skb);
}
#else
int i;
for (i = 0; i < ctx->nr_user_files; i++) {
struct file *file;
file = io_file_from_index(ctx, i);
if (file)
fput(file);
}
#endif
}
static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
unsigned nr_tables, i;
if (!ctx->file_table)
return -ENXIO;
__io_sqe_files_unregister(ctx);
nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
for (i = 0; i < nr_tables; i++)
kfree(ctx->file_table[i].files);
kfree(ctx->file_table);
ctx->file_table = NULL;
ctx->nr_user_files = 0;
return 0;
}
static void io_sq_thread_stop(struct io_ring_ctx *ctx)
{
if (ctx->sqo_thread) {
wait_for_completion(&ctx->completions[1]);
/*
* The park is a bit of a work-around, without it we get
* warning spews on shutdown with SQPOLL set and affinity
* set to a single CPU.
*/
kthread_park(ctx->sqo_thread);
kthread_stop(ctx->sqo_thread);
ctx->sqo_thread = NULL;
}
}
static void io_finish_async(struct io_ring_ctx *ctx)
{
io_sq_thread_stop(ctx);
if (ctx->io_wq) {
io_wq_destroy(ctx->io_wq);
ctx->io_wq = NULL;
}
}
#if defined(CONFIG_UNIX)
static void io_destruct_skb(struct sk_buff *skb)
{
struct io_ring_ctx *ctx = skb->sk->sk_user_data;
if (ctx->io_wq)
io_wq_flush(ctx->io_wq);
unix_destruct_scm(skb);
}
/*
* Ensure the UNIX gc is aware of our file set, so we are certain that
* the io_uring can be safely unregistered on process exit, even if we have
* loops in the file referencing.
*/
static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
{
struct sock *sk = ctx->ring_sock->sk;
struct scm_fp_list *fpl;
struct sk_buff *skb;
int i, nr_files;
if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
unsigned long inflight = ctx->user->unix_inflight + nr;
if (inflight > task_rlimit(current, RLIMIT_NOFILE))
return -EMFILE;
}
fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
if (!fpl)
return -ENOMEM;
skb = alloc_skb(0, GFP_KERNEL);
if (!skb) {
kfree(fpl);
return -ENOMEM;
}
skb->sk = sk;
nr_files = 0;
fpl->user = get_uid(ctx->user);
for (i = 0; i < nr; i++) {
struct file *file = io_file_from_index(ctx, i + offset);
if (!file)
continue;
fpl->fp[nr_files] = get_file(file);
unix_inflight(fpl->user, fpl->fp[nr_files]);
nr_files++;
}
if (nr_files) {
fpl->max = SCM_MAX_FD;
fpl->count = nr_files;
UNIXCB(skb).fp = fpl;
skb->destructor = io_destruct_skb;
refcount_add(skb->truesize, &sk->sk_wmem_alloc);
skb_queue_head(&sk->sk_receive_queue, skb);
for (i = 0; i < nr_files; i++)
fput(fpl->fp[i]);
} else {
kfree_skb(skb);
kfree(fpl);
}
return 0;
}
/*
* If UNIX sockets are enabled, fd passing can cause a reference cycle which
* causes regular reference counting to break down. We rely on the UNIX
* garbage collection to take care of this problem for us.
*/
static int io_sqe_files_scm(struct io_ring_ctx *ctx)
{
unsigned left, total;
int ret = 0;
total = 0;
left = ctx->nr_user_files;
while (left) {
unsigned this_files = min_t(unsigned, left, SCM_MAX_FD);
ret = __io_sqe_files_scm(ctx, this_files, total);
if (ret)
break;
left -= this_files;
total += this_files;
}
if (!ret)
return 0;
while (total < ctx->nr_user_files) {
struct file *file = io_file_from_index(ctx, total);
if (file)
fput(file);
total++;
}
return ret;
}
#else
static int io_sqe_files_scm(struct io_ring_ctx *ctx)
{
return 0;
}
#endif
static int io_sqe_alloc_file_tables(struct io_ring_ctx *ctx, unsigned nr_tables,
unsigned nr_files)
{
int i;
for (i = 0; i < nr_tables; i++) {
struct fixed_file_table *table = &ctx->file_table[i];
unsigned this_files;
this_files = min(nr_files, IORING_MAX_FILES_TABLE);
table->files = kcalloc(this_files, sizeof(struct file *),
GFP_KERNEL);
if (!table->files)
break;
nr_files -= this_files;
}
if (i == nr_tables)
return 0;
for (i = 0; i < nr_tables; i++) {
struct fixed_file_table *table = &ctx->file_table[i];
kfree(table->files);
}
return 1;
}
static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
__s32 __user *fds = (__s32 __user *) arg;
unsigned nr_tables;
int fd, ret = 0;
unsigned i;
if (ctx->file_table)
return -EBUSY;
if (!nr_args)
return -EINVAL;
if (nr_args > IORING_MAX_FIXED_FILES)
return -EMFILE;
nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
ctx->file_table = kcalloc(nr_tables, sizeof(struct fixed_file_table),
GFP_KERNEL);
if (!ctx->file_table)
return -ENOMEM;
if (io_sqe_alloc_file_tables(ctx, nr_tables, nr_args)) {
kfree(ctx->file_table);
ctx->file_table = NULL;
return -ENOMEM;
}
for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
struct fixed_file_table *table;
unsigned index;
ret = -EFAULT;
if (copy_from_user(&fd, &fds[i], sizeof(fd)))
break;
/* allow sparse sets */
if (fd == -1) {
ret = 0;
continue;
}
table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT];
index = i & IORING_FILE_TABLE_MASK;
table->files[index] = fget(fd);
ret = -EBADF;
if (!table->files[index])
break;
/*
* Don't allow io_uring instances to be registered. If UNIX
* isn't enabled, then this causes a reference cycle and this
* instance can never get freed. If UNIX is enabled we'll
* handle it just fine, but there's still no point in allowing
* a ring fd as it doesn't support regular read/write anyway.
*/
if (table->files[index]->f_op == &io_uring_fops) {
fput(table->files[index]);
break;
}
ret = 0;
}
if (ret) {
for (i = 0; i < ctx->nr_user_files; i++) {
struct file *file;
file = io_file_from_index(ctx, i);
if (file)
fput(file);
}
for (i = 0; i < nr_tables; i++)
kfree(ctx->file_table[i].files);
kfree(ctx->file_table);
ctx->file_table = NULL;
ctx->nr_user_files = 0;
return ret;
}
ret = io_sqe_files_scm(ctx);
if (ret)
io_sqe_files_unregister(ctx);
return ret;
}
static void io_sqe_file_unregister(struct io_ring_ctx *ctx, int index)
{
#if defined(CONFIG_UNIX)
struct file *file = io_file_from_index(ctx, index);
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff_head list, *head = &sock->sk_receive_queue;
struct sk_buff *skb;
int i;
__skb_queue_head_init(&list);
/*
* Find the skb that holds this file in its SCM_RIGHTS. When found,
* remove this entry and rearrange the file array.
*/
skb = skb_dequeue(head);
while (skb) {
struct scm_fp_list *fp;
fp = UNIXCB(skb).fp;
for (i = 0; i < fp->count; i++) {
int left;
if (fp->fp[i] != file)
continue;
unix_notinflight(fp->user, fp->fp[i]);
left = fp->count - 1 - i;
if (left) {
memmove(&fp->fp[i], &fp->fp[i + 1],
left * sizeof(struct file *));
}
fp->count--;
if (!fp->count) {
kfree_skb(skb);
skb = NULL;
} else {
__skb_queue_tail(&list, skb);
}
fput(file);
file = NULL;
break;
}
if (!file)
break;
__skb_queue_tail(&list, skb);
skb = skb_dequeue(head);
}
if (skb_peek(&list)) {
spin_lock_irq(&head->lock);
while ((skb = __skb_dequeue(&list)) != NULL)
__skb_queue_tail(head, skb);
spin_unlock_irq(&head->lock);
}
#else
fput(io_file_from_index(ctx, index));
#endif
}
static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
int index)
{
#if defined(CONFIG_UNIX)
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff_head *head = &sock->sk_receive_queue;
struct sk_buff *skb;
/*
* See if we can merge this file into an existing skb SCM_RIGHTS
* file set. If there's no room, fall back to allocating a new skb
* and filling it in.
*/
spin_lock_irq(&head->lock);
skb = skb_peek(head);
if (skb) {
struct scm_fp_list *fpl = UNIXCB(skb).fp;
if (fpl->count < SCM_MAX_FD) {
__skb_unlink(skb, head);
spin_unlock_irq(&head->lock);
fpl->fp[fpl->count] = get_file(file);
unix_inflight(fpl->user, fpl->fp[fpl->count]);
fpl->count++;
spin_lock_irq(&head->lock);
__skb_queue_head(head, skb);
} else {
skb = NULL;
}
}
spin_unlock_irq(&head->lock);
if (skb) {
fput(file);
return 0;
}
return __io_sqe_files_scm(ctx, 1, index);
#else
return 0;
#endif
}
static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
struct io_uring_files_update up;
__s32 __user *fds;
int fd, i, err;
__u32 done;
if (!ctx->file_table)
return -ENXIO;
if (!nr_args)
return -EINVAL;
if (copy_from_user(&up, arg, sizeof(up)))
return -EFAULT;
if (check_add_overflow(up.offset, nr_args, &done))
return -EOVERFLOW;
if (done > ctx->nr_user_files)
return -EINVAL;
done = 0;
fds = (__s32 __user *) up.fds;
while (nr_args) {
struct fixed_file_table *table;
unsigned index;
err = 0;
if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
err = -EFAULT;
break;
}
i = array_index_nospec(up.offset, ctx->nr_user_files);
table = &ctx->file_table[i >> IORING_FILE_TABLE_SHIFT];
index = i & IORING_FILE_TABLE_MASK;
if (table->files[index]) {
io_sqe_file_unregister(ctx, i);
table->files[index] = NULL;
}
if (fd != -1) {
struct file *file;
file = fget(fd);
if (!file) {
err = -EBADF;
break;
}
/*
* Don't allow io_uring instances to be registered. If
* UNIX isn't enabled, then this causes a reference
* cycle and this instance can never get freed. If UNIX
* is enabled we'll handle it just fine, but there's
* still no point in allowing a ring fd as it doesn't
* support regular read/write anyway.
*/
if (file->f_op == &io_uring_fops) {
fput(file);
err = -EBADF;
break;
}
table->files[index] = file;
err = io_sqe_file_register(ctx, file, i);
if (err)
break;
}
nr_args--;
done++;
up.offset++;
}
return done ? done : err;
}
static void io_put_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
io_put_req(req);
}
static void io_get_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
refcount_inc(&req->refs);
}
static int io_sq_offload_start(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_wq_data data;
unsigned concurrency;
int ret;
init_waitqueue_head(&ctx->sqo_wait);
mmgrab(current->mm);
ctx->sqo_mm = current->mm;
if (ctx->flags & IORING_SETUP_SQPOLL) {
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto err;
ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
if (!ctx->sq_thread_idle)
ctx->sq_thread_idle = HZ;
if (p->flags & IORING_SETUP_SQ_AFF) {
int cpu = p->sq_thread_cpu;
ret = -EINVAL;
if (cpu >= nr_cpu_ids)
goto err;
if (!cpu_online(cpu))
goto err;
ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,
ctx, cpu,
"io_uring-sq");
} else {
ctx->sqo_thread = kthread_create(io_sq_thread, ctx,
"io_uring-sq");
}
if (IS_ERR(ctx->sqo_thread)) {
ret = PTR_ERR(ctx->sqo_thread);
ctx->sqo_thread = NULL;
goto err;
}
wake_up_process(ctx->sqo_thread);
} else if (p->flags & IORING_SETUP_SQ_AFF) {
/* Can't have SQ_AFF without SQPOLL */
ret = -EINVAL;
goto err;
}
data.mm = ctx->sqo_mm;
data.user = ctx->user;
data.creds = ctx->creds;
data.get_work = io_get_work;
data.put_work = io_put_work;
/* Do QD, or 4 * CPUS, whatever is smallest */
concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
ctx->io_wq = io_wq_create(concurrency, &data);
if (IS_ERR(ctx->io_wq)) {
ret = PTR_ERR(ctx->io_wq);
ctx->io_wq = NULL;
goto err;
}
return 0;
err:
io_finish_async(ctx);
mmdrop(ctx->sqo_mm);
ctx->sqo_mm = NULL;
return ret;
}
static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages)
{
atomic_long_sub(nr_pages, &user->locked_vm);
}
static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
{
unsigned long page_limit, cur_pages, new_pages;
/* Don't allow more pages than we can safely lock */
page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
do {
cur_pages = atomic_long_read(&user->locked_vm);
new_pages = cur_pages + nr_pages;
if (new_pages > page_limit)
return -ENOMEM;
} while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
new_pages) != cur_pages);
return 0;
}
static void io_mem_free(void *ptr)
{
struct page *page;
if (!ptr)
return;
page = virt_to_head_page(ptr);
if (put_page_testzero(page))
free_compound_page(page);
}
static void *io_mem_alloc(size_t size)
{
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
__GFP_NORETRY;
return (void *) __get_free_pages(gfp_flags, get_order(size));
}
static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
size_t *sq_offset)
{
struct io_rings *rings;
size_t off, sq_array_size;
off = struct_size(rings, cqes, cq_entries);
if (off == SIZE_MAX)
return SIZE_MAX;
#ifdef CONFIG_SMP
off = ALIGN(off, SMP_CACHE_BYTES);
if (off == 0)
return SIZE_MAX;
#endif
sq_array_size = array_size(sizeof(u32), sq_entries);
if (sq_array_size == SIZE_MAX)
return SIZE_MAX;
if (check_add_overflow(off, sq_array_size, &off))
return SIZE_MAX;
if (sq_offset)
*sq_offset = off;
return off;
}
static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
{
size_t pages;
pages = (size_t)1 << get_order(
rings_size(sq_entries, cq_entries, NULL));
pages += (size_t)1 << get_order(
array_size(sizeof(struct io_uring_sqe), sq_entries));
return pages;
}
static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
{
int i, j;
if (!ctx->user_bufs)
return -ENXIO;
for (i = 0; i < ctx->nr_user_bufs; i++) {
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
for (j = 0; j < imu->nr_bvecs; j++)
put_user_page(imu->bvec[j].bv_page);
if (ctx->account_mem)
io_unaccount_mem(ctx->user, imu->nr_bvecs);
kvfree(imu->bvec);
imu->nr_bvecs = 0;
}
kfree(ctx->user_bufs);
ctx->user_bufs = NULL;
ctx->nr_user_bufs = 0;
return 0;
}
static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
void __user *arg, unsigned index)
{
struct iovec __user *src;
#ifdef CONFIG_COMPAT
if (ctx->compat) {
struct compat_iovec __user *ciovs;
struct compat_iovec ciov;
ciovs = (struct compat_iovec __user *) arg;
if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
return -EFAULT;
dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
dst->iov_len = ciov.iov_len;
return 0;
}
#endif
src = (struct iovec __user *) arg;
if (copy_from_user(dst, &src[index], sizeof(*dst)))
return -EFAULT;
return 0;
}
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
struct vm_area_struct **vmas = NULL;
struct page **pages = NULL;
int i, j, got_pages = 0;
int ret = -EINVAL;
if (ctx->user_bufs)
return -EBUSY;
if (!nr_args || nr_args > UIO_MAXIOV)
return -EINVAL;
ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
GFP_KERNEL);
if (!ctx->user_bufs)
return -ENOMEM;
for (i = 0; i < nr_args; i++) {
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
unsigned long off, start, end, ubuf;
int pret, nr_pages;
struct iovec iov;
size_t size;
ret = io_copy_iov(ctx, &iov, arg, i);
if (ret)
goto err;
/*
* Don't impose further limits on the size and buffer
* constraints here, we'll -EINVAL later when IO is
* submitted if they are wrong.
*/
ret = -EFAULT;
if (!iov.iov_base || !iov.iov_len)
goto err;
/* arbitrary limit, but we need something */
if (iov.iov_len > SZ_1G)
goto err;
ubuf = (unsigned long) iov.iov_base;
end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
start = ubuf >> PAGE_SHIFT;
nr_pages = end - start;
if (ctx->account_mem) {
ret = io_account_mem(ctx->user, nr_pages);
if (ret)
goto err;
}
ret = 0;
if (!pages || nr_pages > got_pages) {
kfree(vmas);
kfree(pages);
pages = kvmalloc_array(nr_pages, sizeof(struct page *),
GFP_KERNEL);
vmas = kvmalloc_array(nr_pages,
sizeof(struct vm_area_struct *),
GFP_KERNEL);
if (!pages || !vmas) {
ret = -ENOMEM;
if (ctx->account_mem)
io_unaccount_mem(ctx->user, nr_pages);
goto err;
}
got_pages = nr_pages;
}
imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
GFP_KERNEL);
ret = -ENOMEM;
if (!imu->bvec) {
if (ctx->account_mem)
io_unaccount_mem(ctx->user, nr_pages);
goto err;
}
ret = 0;
down_read(&current->mm->mmap_sem);
pret = get_user_pages(ubuf, nr_pages,
FOLL_WRITE | FOLL_LONGTERM,
pages, vmas);
if (pret == nr_pages) {
/* don't support file backed memory */
for (j = 0; j < nr_pages; j++) {
struct vm_area_struct *vma = vmas[j];
if (vma->vm_file &&
!is_file_hugepages(vma->vm_file)) {
ret = -EOPNOTSUPP;
break;
}
}
} else {
ret = pret < 0 ? pret : -EFAULT;
}
up_read(&current->mm->mmap_sem);
if (ret) {
/*
* if we did partial map, or found file backed vmas,
* release any pages we did get
*/
if (pret > 0)
put_user_pages(pages, pret);
if (ctx->account_mem)
io_unaccount_mem(ctx->user, nr_pages);
kvfree(imu->bvec);
goto err;
}
off = ubuf & ~PAGE_MASK;
size = iov.iov_len;
for (j = 0; j < nr_pages; j++) {
size_t vec_len;
vec_len = min_t(size_t, size, PAGE_SIZE - off);
imu->bvec[j].bv_page = pages[j];
imu->bvec[j].bv_len = vec_len;
imu->bvec[j].bv_offset = off;
off = 0;
size -= vec_len;
}
/* store original address for later verification */
imu->ubuf = ubuf;
imu->len = iov.iov_len;
imu->nr_bvecs = nr_pages;
ctx->nr_user_bufs++;
}
kvfree(pages);
kvfree(vmas);
return 0;
err:
kvfree(pages);
kvfree(vmas);
io_sqe_buffer_unregister(ctx);
return ret;
}
static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
{
__s32 __user *fds = arg;
int fd;
if (ctx->cq_ev_fd)
return -EBUSY;
if (copy_from_user(&fd, fds, sizeof(*fds)))
return -EFAULT;
ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
if (IS_ERR(ctx->cq_ev_fd)) {
int ret = PTR_ERR(ctx->cq_ev_fd);
ctx->cq_ev_fd = NULL;
return ret;
}
return 0;
}
static int io_eventfd_unregister(struct io_ring_ctx *ctx)
{
if (ctx->cq_ev_fd) {
eventfd_ctx_put(ctx->cq_ev_fd);
ctx->cq_ev_fd = NULL;
return 0;
}
return -ENXIO;
}
static void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
io_finish_async(ctx);
if (ctx->sqo_mm)
mmdrop(ctx->sqo_mm);
io_iopoll_reap_events(ctx);
io_sqe_buffer_unregister(ctx);
io_sqe_files_unregister(ctx);
io_eventfd_unregister(ctx);
#if defined(CONFIG_UNIX)
if (ctx->ring_sock) {
ctx->ring_sock->file = NULL; /* so that iput() is called */
sock_release(ctx->ring_sock);
}
#endif
io_mem_free(ctx->rings);
io_mem_free(ctx->sq_sqes);
percpu_ref_exit(&ctx->refs);
if (ctx->account_mem)
io_unaccount_mem(ctx->user,
ring_pages(ctx->sq_entries, ctx->cq_entries));
free_uid(ctx->user);
put_cred(ctx->creds);
kfree(ctx->completions);
kfree(ctx->cancel_hash);
kmem_cache_free(req_cachep, ctx->fallback_req);
kfree(ctx);
}
static __poll_t io_uring_poll(struct file *file, poll_table *wait)
{
struct io_ring_ctx *ctx = file->private_data;
__poll_t mask = 0;
poll_wait(file, &ctx->cq_wait, wait);
/*
* synchronizes with barrier from wq_has_sleeper call in
* io_commit_cqring
*/
smp_rmb();
if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head !=
ctx->rings->sq_ring_entries)
mask |= EPOLLOUT | EPOLLWRNORM;
if (READ_ONCE(ctx->rings->cq.head) != ctx->cached_cq_tail)
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
static int io_uring_fasync(int fd, struct file *file, int on)
{
struct io_ring_ctx *ctx = file->private_data;
return fasync_helper(fd, file, on, &ctx->cq_fasync);
}
static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
mutex_lock(&ctx->uring_lock);
percpu_ref_kill(&ctx->refs);
mutex_unlock(&ctx->uring_lock);
io_kill_timeouts(ctx);
io_poll_remove_all(ctx);
if (ctx->io_wq)
io_wq_cancel_all(ctx->io_wq);
io_iopoll_reap_events(ctx);
/* if we failed setting up the ctx, we might not have any rings */
if (ctx->rings)
io_cqring_overflow_flush(ctx, true);
wait_for_completion(&ctx->completions[0]);
io_ring_ctx_free(ctx);
}
static int io_uring_release(struct inode *inode, struct file *file)
{
struct io_ring_ctx *ctx = file->private_data;
file->private_data = NULL;
io_ring_ctx_wait_and_kill(ctx);
return 0;
}
static void io_uring_cancel_files(struct io_ring_ctx *ctx,
struct files_struct *files)
{
struct io_kiocb *req;
DEFINE_WAIT(wait);
while (!list_empty_careful(&ctx->inflight_list)) {
struct io_kiocb *cancel_req = NULL;
spin_lock_irq(&ctx->inflight_lock);
list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
if (req->work.files != files)
continue;
/* req is being completed, ignore */
if (!refcount_inc_not_zero(&req->refs))
continue;
cancel_req = req;
break;
}
if (cancel_req)
prepare_to_wait(&ctx->inflight_wait, &wait,
TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&ctx->inflight_lock);
/* We need to keep going until we don't find a matching req */
if (!cancel_req)
break;
io_wq_cancel_work(ctx->io_wq, &cancel_req->work);
io_put_req(cancel_req);
schedule();
}
finish_wait(&ctx->inflight_wait, &wait);
}
static int io_uring_flush(struct file *file, void *data)
{
struct io_ring_ctx *ctx = file->private_data;
io_uring_cancel_files(ctx, data);
if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) {
io_cqring_overflow_flush(ctx, true);
io_wq_cancel_all(ctx->io_wq);
}
return 0;
}
static void *io_uring_validate_mmap_request(struct file *file,
loff_t pgoff, size_t sz)
{
struct io_ring_ctx *ctx = file->private_data;
loff_t offset = pgoff << PAGE_SHIFT;
struct page *page;
void *ptr;
switch (offset) {
case IORING_OFF_SQ_RING:
case IORING_OFF_CQ_RING:
ptr = ctx->rings;
break;
case IORING_OFF_SQES:
ptr = ctx->sq_sqes;
break;
default:
return ERR_PTR(-EINVAL);
}
page = virt_to_head_page(ptr);
if (sz > page_size(page))
return ERR_PTR(-EINVAL);
return ptr;
}
#ifdef CONFIG_MMU
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
size_t sz = vma->vm_end - vma->vm_start;
unsigned long pfn;
void *ptr;
ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
}
#else /* !CONFIG_MMU */
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
}
static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
{
return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
}
static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
void *ptr;
ptr = io_uring_validate_mmap_request(file, pgoff, len);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
return (unsigned long) ptr;
}
#endif /* !CONFIG_MMU */
SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
u32, min_complete, u32, flags, const sigset_t __user *, sig,
size_t, sigsz)
{
struct io_ring_ctx *ctx;
long ret = -EBADF;
int submitted = 0;
struct fd f;
if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP))
return -EINVAL;
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -EOPNOTSUPP;
if (f.file->f_op != &io_uring_fops)
goto out_fput;
ret = -ENXIO;
ctx = f.file->private_data;
if (!percpu_ref_tryget(&ctx->refs))
goto out_fput;
/*
* For SQ polling, the thread will do all submissions and completions.
* Just return the requested submit count, and wake the thread if
* we were asked to.
*/
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (!list_empty_careful(&ctx->cq_overflow_list))
io_cqring_overflow_flush(ctx, false);
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sqo_wait);
submitted = to_submit;
} else if (to_submit) {
struct mm_struct *cur_mm;
to_submit = min(to_submit, ctx->sq_entries);
mutex_lock(&ctx->uring_lock);
/* already have mm, so io_submit_sqes() won't try to grab it */
cur_mm = ctx->sqo_mm;
submitted = io_submit_sqes(ctx, to_submit, f.file, fd,
&cur_mm, false);
mutex_unlock(&ctx->uring_lock);
if (submitted != to_submit)
goto out;
}
if (flags & IORING_ENTER_GETEVENTS) {
unsigned nr_events = 0;
min_complete = min(min_complete, ctx->cq_entries);
if (ctx->flags & IORING_SETUP_IOPOLL) {
ret = io_iopoll_check(ctx, &nr_events, min_complete);
} else {
ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
}
}
out:
percpu_ref_put(&ctx->refs);
out_fput:
fdput(f);
return submitted ? submitted : ret;
}
static const struct file_operations io_uring_fops = {
.release = io_uring_release,
.flush = io_uring_flush,
.mmap = io_uring_mmap,
#ifndef CONFIG_MMU
.get_unmapped_area = io_uring_nommu_get_unmapped_area,
.mmap_capabilities = io_uring_nommu_mmap_capabilities,
#endif
.poll = io_uring_poll,
.fasync = io_uring_fasync,
};
static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_rings *rings;
size_t size, sq_array_offset;
size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
if (size == SIZE_MAX)
return -EOVERFLOW;
rings = io_mem_alloc(size);
if (!rings)
return -ENOMEM;
ctx->rings = rings;
ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
rings->sq_ring_mask = p->sq_entries - 1;
rings->cq_ring_mask = p->cq_entries - 1;
rings->sq_ring_entries = p->sq_entries;
rings->cq_ring_entries = p->cq_entries;
ctx->sq_mask = rings->sq_ring_mask;
ctx->cq_mask = rings->cq_ring_mask;
ctx->sq_entries = rings->sq_ring_entries;
ctx->cq_entries = rings->cq_ring_entries;
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
if (size == SIZE_MAX) {
io_mem_free(ctx->rings);
ctx->rings = NULL;
return -EOVERFLOW;
}
ctx->sq_sqes = io_mem_alloc(size);
if (!ctx->sq_sqes) {
io_mem_free(ctx->rings);
ctx->rings = NULL;
return -ENOMEM;
}
return 0;
}
/*
* Allocate an anonymous fd, this is what constitutes the application
* visible backing of an io_uring instance. The application mmaps this
* fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
* we have to tie this fd to a socket for file garbage collection purposes.
*/
static int io_uring_get_fd(struct io_ring_ctx *ctx)
{
struct file *file;
int ret;
#if defined(CONFIG_UNIX)
ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
&ctx->ring_sock);
if (ret)
return ret;
#endif
ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
if (ret < 0)
goto err;
file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx,
O_RDWR | O_CLOEXEC);
if (IS_ERR(file)) {
put_unused_fd(ret);
ret = PTR_ERR(file);
goto err;
}
#if defined(CONFIG_UNIX)
ctx->ring_sock->file = file;
ctx->ring_sock->sk->sk_user_data = ctx;
#endif
fd_install(ret, file);
return ret;
err:
#if defined(CONFIG_UNIX)
sock_release(ctx->ring_sock);
ctx->ring_sock = NULL;
#endif
return ret;
}
static int io_uring_create(unsigned entries, struct io_uring_params *p)
{
struct user_struct *user = NULL;
struct io_ring_ctx *ctx;
bool account_mem;
int ret;
if (!entries || entries > IORING_MAX_ENTRIES)
return -EINVAL;
/*
* Use twice as many entries for the CQ ring. It's possible for the
* application to drive a higher depth than the size of the SQ ring,
* since the sqes are only used at submission time. This allows for
* some flexibility in overcommitting a bit. If the application has
* set IORING_SETUP_CQSIZE, it will have passed in the desired number
* of CQ ring entries manually.
*/
p->sq_entries = roundup_pow_of_two(entries);
if (p->flags & IORING_SETUP_CQSIZE) {
/*
* If IORING_SETUP_CQSIZE is set, we do the same roundup
* to a power-of-two, if it isn't already. We do NOT impose
* any cq vs sq ring sizing.
*/
if (p->cq_entries < p->sq_entries || p->cq_entries > IORING_MAX_CQ_ENTRIES)
return -EINVAL;
p->cq_entries = roundup_pow_of_two(p->cq_entries);
} else {
p->cq_entries = 2 * p->sq_entries;
}
user = get_uid(current_user());
account_mem = !capable(CAP_IPC_LOCK);
if (account_mem) {
ret = io_account_mem(user,
ring_pages(p->sq_entries, p->cq_entries));
if (ret) {
free_uid(user);
return ret;
}
}
ctx = io_ring_ctx_alloc(p);
if (!ctx) {
if (account_mem)
io_unaccount_mem(user, ring_pages(p->sq_entries,
p->cq_entries));
free_uid(user);
return -ENOMEM;
}
ctx->compat = in_compat_syscall();
ctx->account_mem = account_mem;
ctx->user = user;
ctx->creds = get_current_cred();
ret = io_allocate_scq_urings(ctx, p);
if (ret)
goto err;
ret = io_sq_offload_start(ctx, p);
if (ret)
goto err;
memset(&p->sq_off, 0, sizeof(p->sq_off));
p->sq_off.head = offsetof(struct io_rings, sq.head);
p->sq_off.tail = offsetof(struct io_rings, sq.tail);
p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
p->sq_off.flags = offsetof(struct io_rings, sq_flags);
p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
memset(&p->cq_off, 0, sizeof(p->cq_off));
p->cq_off.head = offsetof(struct io_rings, cq.head);
p->cq_off.tail = offsetof(struct io_rings, cq.tail);
p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
p->cq_off.cqes = offsetof(struct io_rings, cqes);
/*
* Install ring fd as the very last thing, so we don't risk someone
* having closed it before we finish setup
*/
ret = io_uring_get_fd(ctx);
if (ret < 0)
goto err;
p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
IORING_FEAT_SUBMIT_STABLE;
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
return ret;
err:
io_ring_ctx_wait_and_kill(ctx);
return ret;
}
/*
* Sets up an aio uring context, and returns the fd. Applications asks for a
* ring size, we return the actual sq/cq ring sizes (among other things) in the
* params structure passed in.
*/
static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
{
struct io_uring_params p;
long ret;
int i;
if (copy_from_user(&p, params, sizeof(p)))
return -EFAULT;
for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
if (p.resv[i])
return -EINVAL;
}
if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE))
return -EINVAL;
ret = io_uring_create(entries, &p);
if (ret < 0)
return ret;
if (copy_to_user(params, &p, sizeof(p)))
return -EFAULT;
return ret;
}
SYSCALL_DEFINE2(io_uring_setup, u32, entries,
struct io_uring_params __user *, params)
{
return io_uring_setup(entries, params);
}
static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
void __user *arg, unsigned nr_args)
__releases(ctx->uring_lock)
__acquires(ctx->uring_lock)
{
int ret;
/*
* We're inside the ring mutex, if the ref is already dying, then
* someone else killed the ctx or is already going through
* io_uring_register().
*/
if (percpu_ref_is_dying(&ctx->refs))
return -ENXIO;
percpu_ref_kill(&ctx->refs);
/*
* Drop uring mutex before waiting for references to exit. If another
* thread is currently inside io_uring_enter() it might need to grab
* the uring_lock to make progress. If we hold it here across the drain
* wait, then we can deadlock. It's safe to drop the mutex here, since
* no new references will come in after we've killed the percpu ref.
*/
mutex_unlock(&ctx->uring_lock);
wait_for_completion(&ctx->completions[0]);
mutex_lock(&ctx->uring_lock);
switch (opcode) {
case IORING_REGISTER_BUFFERS:
ret = io_sqe_buffer_register(ctx, arg, nr_args);
break;
case IORING_UNREGISTER_BUFFERS:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_sqe_buffer_unregister(ctx);
break;
case IORING_REGISTER_FILES:
ret = io_sqe_files_register(ctx, arg, nr_args);
break;
case IORING_UNREGISTER_FILES:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_sqe_files_unregister(ctx);
break;
case IORING_REGISTER_FILES_UPDATE:
ret = io_sqe_files_update(ctx, arg, nr_args);
break;
case IORING_REGISTER_EVENTFD:
ret = -EINVAL;
if (nr_args != 1)
break;
ret = io_eventfd_register(ctx, arg);
break;
case IORING_UNREGISTER_EVENTFD:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_eventfd_unregister(ctx);
break;
default:
ret = -EINVAL;
break;
}
/* bring the ctx back to life */
reinit_completion(&ctx->completions[0]);
percpu_ref_reinit(&ctx->refs);
return ret;
}
SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
void __user *, arg, unsigned int, nr_args)
{
struct io_ring_ctx *ctx;
long ret = -EBADF;
struct fd f;
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -EOPNOTSUPP;
if (f.file->f_op != &io_uring_fops)
goto out_fput;
ctx = f.file->private_data;
mutex_lock(&ctx->uring_lock);
ret = __io_uring_register(ctx, opcode, arg, nr_args);
mutex_unlock(&ctx->uring_lock);
trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs,
ctx->cq_ev_fd != NULL, ret);
out_fput:
fdput(f);
return ret;
}
static int __init io_uring_init(void)
{
req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
return 0;
};
__initcall(io_uring_init);
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