mirror of
https://github.com/torvalds/linux.git
synced 2024-12-05 10:32:35 +00:00
0aa69d53ac
-----BEGIN PGP SIGNATURE----- iQJEBAABCAAuFiEEwPw5LcreJtl1+l5K99NY+ylx4KYFAmSV8cEQHGF4Ym9lQGtl cm5lbC5kawAKCRD301j7KXHgpnvZD/0QWstFCe1CSLWaycdC9fhWftFt3hyEIST5 CYEL56UZrDWNkv9xTLe855xvMavjd4sdHlUa8NUPghRQeJyKYgRxHBLXRWmy0uNN l47Zjiwsolmbr3Nt6qViLdCDYmG39ZGNwWo8b6p3ybWYLtzxeOblocOBTPzoCtkS hjo7Z0eMONvsvLX+l0o9IDdWtZIQ2fGo4VYkMIVb6CyxRPpuUuPKbE25qaTx+uBg Fy6Qa3SlaTwzqcg3dttggjIP792L/eETUCWGndg5pJNbrkj/fI4Vm4bEljID76eS HODl+pWHmyM6avVkypr7N3Tp5HKF0OTUa4vJTLIZo1QiRu6zlXphtuvGn+McEmgV hbYmQMYWzqJ22k2iEpCR58pdhmZJC9uB8r4Rwgr/t9GKqt4E+15EzmqkG9cUVMGV rfbBwVLwBUd5+0WHwQ8RzdtaUPt17vSIW/8WhU5zoMGVotqVBHO/H+5BtmKPWWpq fx1etQ8XJVPIxziJvgsEitb1s6KZzJspcONDlLEitmZkflv3gGdVm99KNbXwJpcp m6+FcYQ5d5FivfLPGgpx8go+4M2QuoW2yRGwZHu54buCnpxgNjIk898OjrUrdXCg 3/0m99GXmOWQQl0VrrTr+Fv99nVsQ2hMQzOFJGMYRtHEEc5xiTcJiZmoxmF7T7/C TipyW3czsw== =5Me8 -----END PGP SIGNATURE----- Merge tag 'for-6.5/io_uring-2023-06-23' of git://git.kernel.dk/linux Pull io_uring updates from Jens Axboe: "Nothing major in this release, just a bunch of cleanups and some optimizations around networking mostly. - clean up file request flags handling (Christoph) - clean up request freeing and CQ locking (Pavel) - support for using pre-registering the io_uring fd at setup time (Josh) - Add support for user allocated ring memory, rather than having the kernel allocate it. Mostly for packing rings into a huge page (me) - avoid an unnecessary double retry on receive (me) - maintain ordering for task_work, which also improves performance (me) - misc cleanups/fixes (Pavel, me)" * tag 'for-6.5/io_uring-2023-06-23' of git://git.kernel.dk/linux: (39 commits) io_uring: merge conditional unlock flush helpers io_uring: make io_cq_unlock_post static io_uring: inline __io_cq_unlock io_uring: fix acquire/release annotations io_uring: kill io_cq_unlock() io_uring: remove IOU_F_TWQ_FORCE_NORMAL io_uring: don't batch task put on reqs free io_uring: move io_clean_op() io_uring: inline io_dismantle_req() io_uring: remove io_free_req_tw io_uring: open code io_put_req_find_next io_uring: add helpers to decode the fixed file file_ptr io_uring: use io_file_from_index in io_msg_grab_file io_uring: use io_file_from_index in __io_sync_cancel io_uring: return REQ_F_ flags from io_file_get_flags io_uring: remove io_req_ffs_set io_uring: remove a confusing comment above io_file_get_flags io_uring: remove the mode variable in io_file_get_flags io_uring: remove __io_file_supports_nowait io_uring: wait interruptibly for request completions on exit ...
1045 lines
28 KiB
C
1045 lines
28 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/kernel.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/file.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/poll.h>
|
|
#include <linux/hashtable.h>
|
|
#include <linux/io_uring.h>
|
|
|
|
#include <trace/events/io_uring.h>
|
|
|
|
#include <uapi/linux/io_uring.h>
|
|
|
|
#include "io_uring.h"
|
|
#include "refs.h"
|
|
#include "opdef.h"
|
|
#include "kbuf.h"
|
|
#include "poll.h"
|
|
#include "cancel.h"
|
|
|
|
struct io_poll_update {
|
|
struct file *file;
|
|
u64 old_user_data;
|
|
u64 new_user_data;
|
|
__poll_t events;
|
|
bool update_events;
|
|
bool update_user_data;
|
|
};
|
|
|
|
struct io_poll_table {
|
|
struct poll_table_struct pt;
|
|
struct io_kiocb *req;
|
|
int nr_entries;
|
|
int error;
|
|
bool owning;
|
|
/* output value, set only if arm poll returns >0 */
|
|
__poll_t result_mask;
|
|
};
|
|
|
|
#define IO_POLL_CANCEL_FLAG BIT(31)
|
|
#define IO_POLL_RETRY_FLAG BIT(30)
|
|
#define IO_POLL_REF_MASK GENMASK(29, 0)
|
|
|
|
/*
|
|
* We usually have 1-2 refs taken, 128 is more than enough and we want to
|
|
* maximise the margin between this amount and the moment when it overflows.
|
|
*/
|
|
#define IO_POLL_REF_BIAS 128
|
|
|
|
#define IO_WQE_F_DOUBLE 1
|
|
|
|
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
|
|
void *key);
|
|
|
|
static inline struct io_kiocb *wqe_to_req(struct wait_queue_entry *wqe)
|
|
{
|
|
unsigned long priv = (unsigned long)wqe->private;
|
|
|
|
return (struct io_kiocb *)(priv & ~IO_WQE_F_DOUBLE);
|
|
}
|
|
|
|
static inline bool wqe_is_double(struct wait_queue_entry *wqe)
|
|
{
|
|
unsigned long priv = (unsigned long)wqe->private;
|
|
|
|
return priv & IO_WQE_F_DOUBLE;
|
|
}
|
|
|
|
static bool io_poll_get_ownership_slowpath(struct io_kiocb *req)
|
|
{
|
|
int v;
|
|
|
|
/*
|
|
* poll_refs are already elevated and we don't have much hope for
|
|
* grabbing the ownership. Instead of incrementing set a retry flag
|
|
* to notify the loop that there might have been some change.
|
|
*/
|
|
v = atomic_fetch_or(IO_POLL_RETRY_FLAG, &req->poll_refs);
|
|
if (v & IO_POLL_REF_MASK)
|
|
return false;
|
|
return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
|
|
}
|
|
|
|
/*
|
|
* If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can
|
|
* bump it and acquire ownership. It's disallowed to modify requests while not
|
|
* owning it, that prevents from races for enqueueing task_work's and b/w
|
|
* arming poll and wakeups.
|
|
*/
|
|
static inline bool io_poll_get_ownership(struct io_kiocb *req)
|
|
{
|
|
if (unlikely(atomic_read(&req->poll_refs) >= IO_POLL_REF_BIAS))
|
|
return io_poll_get_ownership_slowpath(req);
|
|
return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK);
|
|
}
|
|
|
|
static void io_poll_mark_cancelled(struct io_kiocb *req)
|
|
{
|
|
atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs);
|
|
}
|
|
|
|
static struct io_poll *io_poll_get_double(struct io_kiocb *req)
|
|
{
|
|
/* pure poll stashes this in ->async_data, poll driven retry elsewhere */
|
|
if (req->opcode == IORING_OP_POLL_ADD)
|
|
return req->async_data;
|
|
return req->apoll->double_poll;
|
|
}
|
|
|
|
static struct io_poll *io_poll_get_single(struct io_kiocb *req)
|
|
{
|
|
if (req->opcode == IORING_OP_POLL_ADD)
|
|
return io_kiocb_to_cmd(req, struct io_poll);
|
|
return &req->apoll->poll;
|
|
}
|
|
|
|
static void io_poll_req_insert(struct io_kiocb *req)
|
|
{
|
|
struct io_hash_table *table = &req->ctx->cancel_table;
|
|
u32 index = hash_long(req->cqe.user_data, table->hash_bits);
|
|
struct io_hash_bucket *hb = &table->hbs[index];
|
|
|
|
spin_lock(&hb->lock);
|
|
hlist_add_head(&req->hash_node, &hb->list);
|
|
spin_unlock(&hb->lock);
|
|
}
|
|
|
|
static void io_poll_req_delete(struct io_kiocb *req, struct io_ring_ctx *ctx)
|
|
{
|
|
struct io_hash_table *table = &req->ctx->cancel_table;
|
|
u32 index = hash_long(req->cqe.user_data, table->hash_bits);
|
|
spinlock_t *lock = &table->hbs[index].lock;
|
|
|
|
spin_lock(lock);
|
|
hash_del(&req->hash_node);
|
|
spin_unlock(lock);
|
|
}
|
|
|
|
static void io_poll_req_insert_locked(struct io_kiocb *req)
|
|
{
|
|
struct io_hash_table *table = &req->ctx->cancel_table_locked;
|
|
u32 index = hash_long(req->cqe.user_data, table->hash_bits);
|
|
|
|
lockdep_assert_held(&req->ctx->uring_lock);
|
|
|
|
hlist_add_head(&req->hash_node, &table->hbs[index].list);
|
|
}
|
|
|
|
static void io_poll_tw_hash_eject(struct io_kiocb *req, struct io_tw_state *ts)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
|
|
if (req->flags & REQ_F_HASH_LOCKED) {
|
|
/*
|
|
* ->cancel_table_locked is protected by ->uring_lock in
|
|
* contrast to per bucket spinlocks. Likely, tctx_task_work()
|
|
* already grabbed the mutex for us, but there is a chance it
|
|
* failed.
|
|
*/
|
|
io_tw_lock(ctx, ts);
|
|
hash_del(&req->hash_node);
|
|
req->flags &= ~REQ_F_HASH_LOCKED;
|
|
} else {
|
|
io_poll_req_delete(req, ctx);
|
|
}
|
|
}
|
|
|
|
static void io_init_poll_iocb(struct io_poll *poll, __poll_t events)
|
|
{
|
|
poll->head = NULL;
|
|
#define IO_POLL_UNMASK (EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP)
|
|
/* mask in events that we always want/need */
|
|
poll->events = events | IO_POLL_UNMASK;
|
|
INIT_LIST_HEAD(&poll->wait.entry);
|
|
init_waitqueue_func_entry(&poll->wait, io_poll_wake);
|
|
}
|
|
|
|
static inline void io_poll_remove_entry(struct io_poll *poll)
|
|
{
|
|
struct wait_queue_head *head = smp_load_acquire(&poll->head);
|
|
|
|
if (head) {
|
|
spin_lock_irq(&head->lock);
|
|
list_del_init(&poll->wait.entry);
|
|
poll->head = NULL;
|
|
spin_unlock_irq(&head->lock);
|
|
}
|
|
}
|
|
|
|
static void io_poll_remove_entries(struct io_kiocb *req)
|
|
{
|
|
/*
|
|
* Nothing to do if neither of those flags are set. Avoid dipping
|
|
* into the poll/apoll/double cachelines if we can.
|
|
*/
|
|
if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL)))
|
|
return;
|
|
|
|
/*
|
|
* While we hold the waitqueue lock and the waitqueue is nonempty,
|
|
* wake_up_pollfree() will wait for us. However, taking the waitqueue
|
|
* lock in the first place can race with the waitqueue being freed.
|
|
*
|
|
* We solve this as eventpoll does: by taking advantage of the fact that
|
|
* all users of wake_up_pollfree() will RCU-delay the actual free. If
|
|
* we enter rcu_read_lock() and see that the pointer to the queue is
|
|
* non-NULL, we can then lock it without the memory being freed out from
|
|
* under us.
|
|
*
|
|
* Keep holding rcu_read_lock() as long as we hold the queue lock, in
|
|
* case the caller deletes the entry from the queue, leaving it empty.
|
|
* In that case, only RCU prevents the queue memory from being freed.
|
|
*/
|
|
rcu_read_lock();
|
|
if (req->flags & REQ_F_SINGLE_POLL)
|
|
io_poll_remove_entry(io_poll_get_single(req));
|
|
if (req->flags & REQ_F_DOUBLE_POLL)
|
|
io_poll_remove_entry(io_poll_get_double(req));
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
enum {
|
|
IOU_POLL_DONE = 0,
|
|
IOU_POLL_NO_ACTION = 1,
|
|
IOU_POLL_REMOVE_POLL_USE_RES = 2,
|
|
IOU_POLL_REISSUE = 3,
|
|
};
|
|
|
|
/*
|
|
* All poll tw should go through this. Checks for poll events, manages
|
|
* references, does rewait, etc.
|
|
*
|
|
* Returns a negative error on failure. IOU_POLL_NO_ACTION when no action
|
|
* require, which is either spurious wakeup or multishot CQE is served.
|
|
* IOU_POLL_DONE when it's done with the request, then the mask is stored in
|
|
* req->cqe.res. IOU_POLL_REMOVE_POLL_USE_RES indicates to remove multishot
|
|
* poll and that the result is stored in req->cqe.
|
|
*/
|
|
static int io_poll_check_events(struct io_kiocb *req, struct io_tw_state *ts)
|
|
{
|
|
int v;
|
|
|
|
/* req->task == current here, checking PF_EXITING is safe */
|
|
if (unlikely(req->task->flags & PF_EXITING))
|
|
return -ECANCELED;
|
|
|
|
do {
|
|
v = atomic_read(&req->poll_refs);
|
|
|
|
if (unlikely(v != 1)) {
|
|
/* tw should be the owner and so have some refs */
|
|
if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK)))
|
|
return IOU_POLL_NO_ACTION;
|
|
if (v & IO_POLL_CANCEL_FLAG)
|
|
return -ECANCELED;
|
|
/*
|
|
* cqe.res contains only events of the first wake up
|
|
* and all others are to be lost. Redo vfs_poll() to get
|
|
* up to date state.
|
|
*/
|
|
if ((v & IO_POLL_REF_MASK) != 1)
|
|
req->cqe.res = 0;
|
|
|
|
if (v & IO_POLL_RETRY_FLAG) {
|
|
req->cqe.res = 0;
|
|
/*
|
|
* We won't find new events that came in between
|
|
* vfs_poll and the ref put unless we clear the
|
|
* flag in advance.
|
|
*/
|
|
atomic_andnot(IO_POLL_RETRY_FLAG, &req->poll_refs);
|
|
v &= ~IO_POLL_RETRY_FLAG;
|
|
}
|
|
}
|
|
|
|
/* the mask was stashed in __io_poll_execute */
|
|
if (!req->cqe.res) {
|
|
struct poll_table_struct pt = { ._key = req->apoll_events };
|
|
req->cqe.res = vfs_poll(req->file, &pt) & req->apoll_events;
|
|
/*
|
|
* We got woken with a mask, but someone else got to
|
|
* it first. The above vfs_poll() doesn't add us back
|
|
* to the waitqueue, so if we get nothing back, we
|
|
* should be safe and attempt a reissue.
|
|
*/
|
|
if (unlikely(!req->cqe.res)) {
|
|
/* Multishot armed need not reissue */
|
|
if (!(req->apoll_events & EPOLLONESHOT))
|
|
continue;
|
|
return IOU_POLL_REISSUE;
|
|
}
|
|
}
|
|
if (req->apoll_events & EPOLLONESHOT)
|
|
return IOU_POLL_DONE;
|
|
|
|
/* multishot, just fill a CQE and proceed */
|
|
if (!(req->flags & REQ_F_APOLL_MULTISHOT)) {
|
|
__poll_t mask = mangle_poll(req->cqe.res &
|
|
req->apoll_events);
|
|
|
|
if (!io_aux_cqe(req, ts->locked, mask,
|
|
IORING_CQE_F_MORE, false)) {
|
|
io_req_set_res(req, mask, 0);
|
|
return IOU_POLL_REMOVE_POLL_USE_RES;
|
|
}
|
|
} else {
|
|
int ret = io_poll_issue(req, ts);
|
|
if (ret == IOU_STOP_MULTISHOT)
|
|
return IOU_POLL_REMOVE_POLL_USE_RES;
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
|
|
/* force the next iteration to vfs_poll() */
|
|
req->cqe.res = 0;
|
|
|
|
/*
|
|
* Release all references, retry if someone tried to restart
|
|
* task_work while we were executing it.
|
|
*/
|
|
} while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs) &
|
|
IO_POLL_REF_MASK);
|
|
|
|
return IOU_POLL_NO_ACTION;
|
|
}
|
|
|
|
void io_poll_task_func(struct io_kiocb *req, struct io_tw_state *ts)
|
|
{
|
|
int ret;
|
|
|
|
ret = io_poll_check_events(req, ts);
|
|
if (ret == IOU_POLL_NO_ACTION)
|
|
return;
|
|
io_poll_remove_entries(req);
|
|
io_poll_tw_hash_eject(req, ts);
|
|
|
|
if (req->opcode == IORING_OP_POLL_ADD) {
|
|
if (ret == IOU_POLL_DONE) {
|
|
struct io_poll *poll;
|
|
|
|
poll = io_kiocb_to_cmd(req, struct io_poll);
|
|
req->cqe.res = mangle_poll(req->cqe.res & poll->events);
|
|
} else if (ret == IOU_POLL_REISSUE) {
|
|
io_req_task_submit(req, ts);
|
|
return;
|
|
} else if (ret != IOU_POLL_REMOVE_POLL_USE_RES) {
|
|
req->cqe.res = ret;
|
|
req_set_fail(req);
|
|
}
|
|
|
|
io_req_set_res(req, req->cqe.res, 0);
|
|
io_req_task_complete(req, ts);
|
|
} else {
|
|
io_tw_lock(req->ctx, ts);
|
|
|
|
if (ret == IOU_POLL_REMOVE_POLL_USE_RES)
|
|
io_req_task_complete(req, ts);
|
|
else if (ret == IOU_POLL_DONE || ret == IOU_POLL_REISSUE)
|
|
io_req_task_submit(req, ts);
|
|
else
|
|
io_req_defer_failed(req, ret);
|
|
}
|
|
}
|
|
|
|
static void __io_poll_execute(struct io_kiocb *req, int mask)
|
|
{
|
|
io_req_set_res(req, mask, 0);
|
|
req->io_task_work.func = io_poll_task_func;
|
|
|
|
trace_io_uring_task_add(req, mask);
|
|
io_req_task_work_add(req);
|
|
}
|
|
|
|
static inline void io_poll_execute(struct io_kiocb *req, int res)
|
|
{
|
|
if (io_poll_get_ownership(req))
|
|
__io_poll_execute(req, res);
|
|
}
|
|
|
|
static void io_poll_cancel_req(struct io_kiocb *req)
|
|
{
|
|
io_poll_mark_cancelled(req);
|
|
/* kick tw, which should complete the request */
|
|
io_poll_execute(req, 0);
|
|
}
|
|
|
|
#define IO_ASYNC_POLL_COMMON (EPOLLONESHOT | EPOLLPRI)
|
|
|
|
static __cold int io_pollfree_wake(struct io_kiocb *req, struct io_poll *poll)
|
|
{
|
|
io_poll_mark_cancelled(req);
|
|
/* we have to kick tw in case it's not already */
|
|
io_poll_execute(req, 0);
|
|
|
|
/*
|
|
* If the waitqueue is being freed early but someone is already
|
|
* holds ownership over it, we have to tear down the request as
|
|
* best we can. That means immediately removing the request from
|
|
* its waitqueue and preventing all further accesses to the
|
|
* waitqueue via the request.
|
|
*/
|
|
list_del_init(&poll->wait.entry);
|
|
|
|
/*
|
|
* Careful: this *must* be the last step, since as soon
|
|
* as req->head is NULL'ed out, the request can be
|
|
* completed and freed, since aio_poll_complete_work()
|
|
* will no longer need to take the waitqueue lock.
|
|
*/
|
|
smp_store_release(&poll->head, NULL);
|
|
return 1;
|
|
}
|
|
|
|
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
|
|
void *key)
|
|
{
|
|
struct io_kiocb *req = wqe_to_req(wait);
|
|
struct io_poll *poll = container_of(wait, struct io_poll, wait);
|
|
__poll_t mask = key_to_poll(key);
|
|
|
|
if (unlikely(mask & POLLFREE))
|
|
return io_pollfree_wake(req, poll);
|
|
|
|
/* for instances that support it check for an event match first */
|
|
if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON)))
|
|
return 0;
|
|
|
|
if (io_poll_get_ownership(req)) {
|
|
/*
|
|
* If we trigger a multishot poll off our own wakeup path,
|
|
* disable multishot as there is a circular dependency between
|
|
* CQ posting and triggering the event.
|
|
*/
|
|
if (mask & EPOLL_URING_WAKE)
|
|
poll->events |= EPOLLONESHOT;
|
|
|
|
/* optional, saves extra locking for removal in tw handler */
|
|
if (mask && poll->events & EPOLLONESHOT) {
|
|
list_del_init(&poll->wait.entry);
|
|
poll->head = NULL;
|
|
if (wqe_is_double(wait))
|
|
req->flags &= ~REQ_F_DOUBLE_POLL;
|
|
else
|
|
req->flags &= ~REQ_F_SINGLE_POLL;
|
|
}
|
|
__io_poll_execute(req, mask);
|
|
}
|
|
return 1;
|
|
}
|
|
|
|
/* fails only when polling is already completing by the first entry */
|
|
static bool io_poll_double_prepare(struct io_kiocb *req)
|
|
{
|
|
struct wait_queue_head *head;
|
|
struct io_poll *poll = io_poll_get_single(req);
|
|
|
|
/* head is RCU protected, see io_poll_remove_entries() comments */
|
|
rcu_read_lock();
|
|
head = smp_load_acquire(&poll->head);
|
|
/*
|
|
* poll arm might not hold ownership and so race for req->flags with
|
|
* io_poll_wake(). There is only one poll entry queued, serialise with
|
|
* it by taking its head lock. As we're still arming the tw hanlder
|
|
* is not going to be run, so there are no races with it.
|
|
*/
|
|
if (head) {
|
|
spin_lock_irq(&head->lock);
|
|
req->flags |= REQ_F_DOUBLE_POLL;
|
|
if (req->opcode == IORING_OP_POLL_ADD)
|
|
req->flags |= REQ_F_ASYNC_DATA;
|
|
spin_unlock_irq(&head->lock);
|
|
}
|
|
rcu_read_unlock();
|
|
return !!head;
|
|
}
|
|
|
|
static void __io_queue_proc(struct io_poll *poll, struct io_poll_table *pt,
|
|
struct wait_queue_head *head,
|
|
struct io_poll **poll_ptr)
|
|
{
|
|
struct io_kiocb *req = pt->req;
|
|
unsigned long wqe_private = (unsigned long) req;
|
|
|
|
/*
|
|
* The file being polled uses multiple waitqueues for poll handling
|
|
* (e.g. one for read, one for write). Setup a separate io_poll
|
|
* if this happens.
|
|
*/
|
|
if (unlikely(pt->nr_entries)) {
|
|
struct io_poll *first = poll;
|
|
|
|
/* double add on the same waitqueue head, ignore */
|
|
if (first->head == head)
|
|
return;
|
|
/* already have a 2nd entry, fail a third attempt */
|
|
if (*poll_ptr) {
|
|
if ((*poll_ptr)->head == head)
|
|
return;
|
|
pt->error = -EINVAL;
|
|
return;
|
|
}
|
|
|
|
poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
|
|
if (!poll) {
|
|
pt->error = -ENOMEM;
|
|
return;
|
|
}
|
|
|
|
/* mark as double wq entry */
|
|
wqe_private |= IO_WQE_F_DOUBLE;
|
|
io_init_poll_iocb(poll, first->events);
|
|
if (!io_poll_double_prepare(req)) {
|
|
/* the request is completing, just back off */
|
|
kfree(poll);
|
|
return;
|
|
}
|
|
*poll_ptr = poll;
|
|
} else {
|
|
/* fine to modify, there is no poll queued to race with us */
|
|
req->flags |= REQ_F_SINGLE_POLL;
|
|
}
|
|
|
|
pt->nr_entries++;
|
|
poll->head = head;
|
|
poll->wait.private = (void *) wqe_private;
|
|
|
|
if (poll->events & EPOLLEXCLUSIVE)
|
|
add_wait_queue_exclusive(head, &poll->wait);
|
|
else
|
|
add_wait_queue(head, &poll->wait);
|
|
}
|
|
|
|
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);
|
|
struct io_poll *poll = io_kiocb_to_cmd(pt->req, struct io_poll);
|
|
|
|
__io_queue_proc(poll, pt, head,
|
|
(struct io_poll **) &pt->req->async_data);
|
|
}
|
|
|
|
static bool io_poll_can_finish_inline(struct io_kiocb *req,
|
|
struct io_poll_table *pt)
|
|
{
|
|
return pt->owning || io_poll_get_ownership(req);
|
|
}
|
|
|
|
static void io_poll_add_hash(struct io_kiocb *req)
|
|
{
|
|
if (req->flags & REQ_F_HASH_LOCKED)
|
|
io_poll_req_insert_locked(req);
|
|
else
|
|
io_poll_req_insert(req);
|
|
}
|
|
|
|
/*
|
|
* Returns 0 when it's handed over for polling. The caller owns the requests if
|
|
* it returns non-zero, but otherwise should not touch it. Negative values
|
|
* contain an error code. When the result is >0, the polling has completed
|
|
* inline and ipt.result_mask is set to the mask.
|
|
*/
|
|
static int __io_arm_poll_handler(struct io_kiocb *req,
|
|
struct io_poll *poll,
|
|
struct io_poll_table *ipt, __poll_t mask,
|
|
unsigned issue_flags)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
|
|
INIT_HLIST_NODE(&req->hash_node);
|
|
req->work.cancel_seq = atomic_read(&ctx->cancel_seq);
|
|
io_init_poll_iocb(poll, mask);
|
|
poll->file = req->file;
|
|
req->apoll_events = poll->events;
|
|
|
|
ipt->pt._key = mask;
|
|
ipt->req = req;
|
|
ipt->error = 0;
|
|
ipt->nr_entries = 0;
|
|
/*
|
|
* Polling is either completed here or via task_work, so if we're in the
|
|
* task context we're naturally serialised with tw by merit of running
|
|
* the same task. When it's io-wq, take the ownership to prevent tw
|
|
* from running. However, when we're in the task context, skip taking
|
|
* it as an optimisation.
|
|
*
|
|
* Note: even though the request won't be completed/freed, without
|
|
* ownership we still can race with io_poll_wake().
|
|
* io_poll_can_finish_inline() tries to deal with that.
|
|
*/
|
|
ipt->owning = issue_flags & IO_URING_F_UNLOCKED;
|
|
atomic_set(&req->poll_refs, (int)ipt->owning);
|
|
|
|
/* io-wq doesn't hold uring_lock */
|
|
if (issue_flags & IO_URING_F_UNLOCKED)
|
|
req->flags &= ~REQ_F_HASH_LOCKED;
|
|
|
|
mask = vfs_poll(req->file, &ipt->pt) & poll->events;
|
|
|
|
if (unlikely(ipt->error || !ipt->nr_entries)) {
|
|
io_poll_remove_entries(req);
|
|
|
|
if (!io_poll_can_finish_inline(req, ipt)) {
|
|
io_poll_mark_cancelled(req);
|
|
return 0;
|
|
} else if (mask && (poll->events & EPOLLET)) {
|
|
ipt->result_mask = mask;
|
|
return 1;
|
|
}
|
|
return ipt->error ?: -EINVAL;
|
|
}
|
|
|
|
if (mask &&
|
|
((poll->events & (EPOLLET|EPOLLONESHOT)) == (EPOLLET|EPOLLONESHOT))) {
|
|
if (!io_poll_can_finish_inline(req, ipt)) {
|
|
io_poll_add_hash(req);
|
|
return 0;
|
|
}
|
|
io_poll_remove_entries(req);
|
|
ipt->result_mask = mask;
|
|
/* no one else has access to the req, forget about the ref */
|
|
return 1;
|
|
}
|
|
|
|
io_poll_add_hash(req);
|
|
|
|
if (mask && (poll->events & EPOLLET) &&
|
|
io_poll_can_finish_inline(req, ipt)) {
|
|
__io_poll_execute(req, mask);
|
|
return 0;
|
|
}
|
|
|
|
if (ipt->owning) {
|
|
/*
|
|
* Try to release ownership. If we see a change of state, e.g.
|
|
* poll was waken up, queue up a tw, it'll deal with it.
|
|
*/
|
|
if (atomic_cmpxchg(&req->poll_refs, 1, 0) != 1)
|
|
__io_poll_execute(req, 0);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static void io_async_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);
|
|
struct async_poll *apoll = pt->req->apoll;
|
|
|
|
__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
|
|
}
|
|
|
|
/*
|
|
* We can't reliably detect loops in repeated poll triggers and issue
|
|
* subsequently failing. But rather than fail these immediately, allow a
|
|
* certain amount of retries before we give up. Given that this condition
|
|
* should _rarely_ trigger even once, we should be fine with a larger value.
|
|
*/
|
|
#define APOLL_MAX_RETRY 128
|
|
|
|
static struct async_poll *io_req_alloc_apoll(struct io_kiocb *req,
|
|
unsigned issue_flags)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
struct io_cache_entry *entry;
|
|
struct async_poll *apoll;
|
|
|
|
if (req->flags & REQ_F_POLLED) {
|
|
apoll = req->apoll;
|
|
kfree(apoll->double_poll);
|
|
} else if (!(issue_flags & IO_URING_F_UNLOCKED)) {
|
|
entry = io_alloc_cache_get(&ctx->apoll_cache);
|
|
if (entry == NULL)
|
|
goto alloc_apoll;
|
|
apoll = container_of(entry, struct async_poll, cache);
|
|
apoll->poll.retries = APOLL_MAX_RETRY;
|
|
} else {
|
|
alloc_apoll:
|
|
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
|
|
if (unlikely(!apoll))
|
|
return NULL;
|
|
apoll->poll.retries = APOLL_MAX_RETRY;
|
|
}
|
|
apoll->double_poll = NULL;
|
|
req->apoll = apoll;
|
|
if (unlikely(!--apoll->poll.retries))
|
|
return NULL;
|
|
return apoll;
|
|
}
|
|
|
|
int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags)
|
|
{
|
|
const struct io_issue_def *def = &io_issue_defs[req->opcode];
|
|
struct async_poll *apoll;
|
|
struct io_poll_table ipt;
|
|
__poll_t mask = POLLPRI | POLLERR | EPOLLET;
|
|
int ret;
|
|
|
|
/*
|
|
* apoll requests already grab the mutex to complete in the tw handler,
|
|
* so removal from the mutex-backed hash is free, use it by default.
|
|
*/
|
|
req->flags |= REQ_F_HASH_LOCKED;
|
|
|
|
if (!def->pollin && !def->pollout)
|
|
return IO_APOLL_ABORTED;
|
|
if (!file_can_poll(req->file))
|
|
return IO_APOLL_ABORTED;
|
|
if (!(req->flags & REQ_F_APOLL_MULTISHOT))
|
|
mask |= EPOLLONESHOT;
|
|
|
|
if (def->pollin) {
|
|
mask |= EPOLLIN | EPOLLRDNORM;
|
|
|
|
/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
|
|
if (req->flags & REQ_F_CLEAR_POLLIN)
|
|
mask &= ~EPOLLIN;
|
|
} else {
|
|
mask |= EPOLLOUT | EPOLLWRNORM;
|
|
}
|
|
if (def->poll_exclusive)
|
|
mask |= EPOLLEXCLUSIVE;
|
|
|
|
apoll = io_req_alloc_apoll(req, issue_flags);
|
|
if (!apoll)
|
|
return IO_APOLL_ABORTED;
|
|
req->flags &= ~(REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL);
|
|
req->flags |= REQ_F_POLLED;
|
|
ipt.pt._qproc = io_async_queue_proc;
|
|
|
|
io_kbuf_recycle(req, issue_flags);
|
|
|
|
ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, issue_flags);
|
|
if (ret)
|
|
return ret > 0 ? IO_APOLL_READY : IO_APOLL_ABORTED;
|
|
trace_io_uring_poll_arm(req, mask, apoll->poll.events);
|
|
return IO_APOLL_OK;
|
|
}
|
|
|
|
static __cold bool io_poll_remove_all_table(struct task_struct *tsk,
|
|
struct io_hash_table *table,
|
|
bool cancel_all)
|
|
{
|
|
unsigned nr_buckets = 1U << table->hash_bits;
|
|
struct hlist_node *tmp;
|
|
struct io_kiocb *req;
|
|
bool found = false;
|
|
int i;
|
|
|
|
for (i = 0; i < nr_buckets; i++) {
|
|
struct io_hash_bucket *hb = &table->hbs[i];
|
|
|
|
spin_lock(&hb->lock);
|
|
hlist_for_each_entry_safe(req, tmp, &hb->list, hash_node) {
|
|
if (io_match_task_safe(req, tsk, cancel_all)) {
|
|
hlist_del_init(&req->hash_node);
|
|
io_poll_cancel_req(req);
|
|
found = true;
|
|
}
|
|
}
|
|
spin_unlock(&hb->lock);
|
|
}
|
|
return found;
|
|
}
|
|
|
|
/*
|
|
* Returns true if we found and killed one or more poll requests
|
|
*/
|
|
__cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk,
|
|
bool cancel_all)
|
|
__must_hold(&ctx->uring_lock)
|
|
{
|
|
bool ret;
|
|
|
|
ret = io_poll_remove_all_table(tsk, &ctx->cancel_table, cancel_all);
|
|
ret |= io_poll_remove_all_table(tsk, &ctx->cancel_table_locked, cancel_all);
|
|
return ret;
|
|
}
|
|
|
|
static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, bool poll_only,
|
|
struct io_cancel_data *cd,
|
|
struct io_hash_table *table,
|
|
struct io_hash_bucket **out_bucket)
|
|
{
|
|
struct io_kiocb *req;
|
|
u32 index = hash_long(cd->data, table->hash_bits);
|
|
struct io_hash_bucket *hb = &table->hbs[index];
|
|
|
|
*out_bucket = NULL;
|
|
|
|
spin_lock(&hb->lock);
|
|
hlist_for_each_entry(req, &hb->list, hash_node) {
|
|
if (cd->data != req->cqe.user_data)
|
|
continue;
|
|
if (poll_only && req->opcode != IORING_OP_POLL_ADD)
|
|
continue;
|
|
if (cd->flags & IORING_ASYNC_CANCEL_ALL) {
|
|
if (cd->seq == req->work.cancel_seq)
|
|
continue;
|
|
req->work.cancel_seq = cd->seq;
|
|
}
|
|
*out_bucket = hb;
|
|
return req;
|
|
}
|
|
spin_unlock(&hb->lock);
|
|
return NULL;
|
|
}
|
|
|
|
static struct io_kiocb *io_poll_file_find(struct io_ring_ctx *ctx,
|
|
struct io_cancel_data *cd,
|
|
struct io_hash_table *table,
|
|
struct io_hash_bucket **out_bucket)
|
|
{
|
|
unsigned nr_buckets = 1U << table->hash_bits;
|
|
struct io_kiocb *req;
|
|
int i;
|
|
|
|
*out_bucket = NULL;
|
|
|
|
for (i = 0; i < nr_buckets; i++) {
|
|
struct io_hash_bucket *hb = &table->hbs[i];
|
|
|
|
spin_lock(&hb->lock);
|
|
hlist_for_each_entry(req, &hb->list, hash_node) {
|
|
if (!(cd->flags & IORING_ASYNC_CANCEL_ANY) &&
|
|
req->file != cd->file)
|
|
continue;
|
|
if (cd->seq == req->work.cancel_seq)
|
|
continue;
|
|
req->work.cancel_seq = cd->seq;
|
|
*out_bucket = hb;
|
|
return req;
|
|
}
|
|
spin_unlock(&hb->lock);
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
static int io_poll_disarm(struct io_kiocb *req)
|
|
{
|
|
if (!req)
|
|
return -ENOENT;
|
|
if (!io_poll_get_ownership(req))
|
|
return -EALREADY;
|
|
io_poll_remove_entries(req);
|
|
hash_del(&req->hash_node);
|
|
return 0;
|
|
}
|
|
|
|
static int __io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
|
|
struct io_hash_table *table)
|
|
{
|
|
struct io_hash_bucket *bucket;
|
|
struct io_kiocb *req;
|
|
|
|
if (cd->flags & (IORING_ASYNC_CANCEL_FD|IORING_ASYNC_CANCEL_ANY))
|
|
req = io_poll_file_find(ctx, cd, table, &bucket);
|
|
else
|
|
req = io_poll_find(ctx, false, cd, table, &bucket);
|
|
|
|
if (req)
|
|
io_poll_cancel_req(req);
|
|
if (bucket)
|
|
spin_unlock(&bucket->lock);
|
|
return req ? 0 : -ENOENT;
|
|
}
|
|
|
|
int io_poll_cancel(struct io_ring_ctx *ctx, struct io_cancel_data *cd,
|
|
unsigned issue_flags)
|
|
{
|
|
int ret;
|
|
|
|
ret = __io_poll_cancel(ctx, cd, &ctx->cancel_table);
|
|
if (ret != -ENOENT)
|
|
return ret;
|
|
|
|
io_ring_submit_lock(ctx, issue_flags);
|
|
ret = __io_poll_cancel(ctx, cd, &ctx->cancel_table_locked);
|
|
io_ring_submit_unlock(ctx, issue_flags);
|
|
return ret;
|
|
}
|
|
|
|
static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe,
|
|
unsigned int flags)
|
|
{
|
|
u32 events;
|
|
|
|
events = READ_ONCE(sqe->poll32_events);
|
|
#ifdef __BIG_ENDIAN
|
|
events = swahw32(events);
|
|
#endif
|
|
if (!(flags & IORING_POLL_ADD_MULTI))
|
|
events |= EPOLLONESHOT;
|
|
if (!(flags & IORING_POLL_ADD_LEVEL))
|
|
events |= EPOLLET;
|
|
return demangle_poll(events) |
|
|
(events & (EPOLLEXCLUSIVE|EPOLLONESHOT|EPOLLET));
|
|
}
|
|
|
|
int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
|
|
{
|
|
struct io_poll_update *upd = io_kiocb_to_cmd(req, struct io_poll_update);
|
|
u32 flags;
|
|
|
|
if (sqe->buf_index || sqe->splice_fd_in)
|
|
return -EINVAL;
|
|
flags = READ_ONCE(sqe->len);
|
|
if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA |
|
|
IORING_POLL_ADD_MULTI))
|
|
return -EINVAL;
|
|
/* meaningless without update */
|
|
if (flags == IORING_POLL_ADD_MULTI)
|
|
return -EINVAL;
|
|
|
|
upd->old_user_data = READ_ONCE(sqe->addr);
|
|
upd->update_events = flags & IORING_POLL_UPDATE_EVENTS;
|
|
upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA;
|
|
|
|
upd->new_user_data = READ_ONCE(sqe->off);
|
|
if (!upd->update_user_data && upd->new_user_data)
|
|
return -EINVAL;
|
|
if (upd->update_events)
|
|
upd->events = io_poll_parse_events(sqe, flags);
|
|
else if (sqe->poll32_events)
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
|
|
{
|
|
struct io_poll *poll = io_kiocb_to_cmd(req, struct io_poll);
|
|
u32 flags;
|
|
|
|
if (sqe->buf_index || sqe->off || sqe->addr)
|
|
return -EINVAL;
|
|
flags = READ_ONCE(sqe->len);
|
|
if (flags & ~IORING_POLL_ADD_MULTI)
|
|
return -EINVAL;
|
|
if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP))
|
|
return -EINVAL;
|
|
|
|
poll->events = io_poll_parse_events(sqe, flags);
|
|
return 0;
|
|
}
|
|
|
|
int io_poll_add(struct io_kiocb *req, unsigned int issue_flags)
|
|
{
|
|
struct io_poll *poll = io_kiocb_to_cmd(req, struct io_poll);
|
|
struct io_poll_table ipt;
|
|
int ret;
|
|
|
|
ipt.pt._qproc = io_poll_queue_proc;
|
|
|
|
/*
|
|
* If sqpoll or single issuer, there is no contention for ->uring_lock
|
|
* and we'll end up holding it in tw handlers anyway.
|
|
*/
|
|
if (req->ctx->flags & (IORING_SETUP_SQPOLL|IORING_SETUP_SINGLE_ISSUER))
|
|
req->flags |= REQ_F_HASH_LOCKED;
|
|
|
|
ret = __io_arm_poll_handler(req, poll, &ipt, poll->events, issue_flags);
|
|
if (ret > 0) {
|
|
io_req_set_res(req, ipt.result_mask, 0);
|
|
return IOU_OK;
|
|
}
|
|
return ret ?: IOU_ISSUE_SKIP_COMPLETE;
|
|
}
|
|
|
|
int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags)
|
|
{
|
|
struct io_poll_update *poll_update = io_kiocb_to_cmd(req, struct io_poll_update);
|
|
struct io_cancel_data cd = { .data = poll_update->old_user_data, };
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
struct io_hash_bucket *bucket;
|
|
struct io_kiocb *preq;
|
|
int ret2, ret = 0;
|
|
struct io_tw_state ts = { .locked = true };
|
|
|
|
io_ring_submit_lock(ctx, issue_flags);
|
|
preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table, &bucket);
|
|
ret2 = io_poll_disarm(preq);
|
|
if (bucket)
|
|
spin_unlock(&bucket->lock);
|
|
if (!ret2)
|
|
goto found;
|
|
if (ret2 != -ENOENT) {
|
|
ret = ret2;
|
|
goto out;
|
|
}
|
|
|
|
preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table_locked, &bucket);
|
|
ret2 = io_poll_disarm(preq);
|
|
if (bucket)
|
|
spin_unlock(&bucket->lock);
|
|
if (ret2) {
|
|
ret = ret2;
|
|
goto out;
|
|
}
|
|
|
|
found:
|
|
if (WARN_ON_ONCE(preq->opcode != IORING_OP_POLL_ADD)) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
if (poll_update->update_events || poll_update->update_user_data) {
|
|
/* only mask one event flags, keep behavior flags */
|
|
if (poll_update->update_events) {
|
|
struct io_poll *poll = io_kiocb_to_cmd(preq, struct io_poll);
|
|
|
|
poll->events &= ~0xffff;
|
|
poll->events |= poll_update->events & 0xffff;
|
|
poll->events |= IO_POLL_UNMASK;
|
|
}
|
|
if (poll_update->update_user_data)
|
|
preq->cqe.user_data = poll_update->new_user_data;
|
|
|
|
ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED);
|
|
/* successfully updated, don't complete poll request */
|
|
if (!ret2 || ret2 == -EIOCBQUEUED)
|
|
goto out;
|
|
}
|
|
|
|
req_set_fail(preq);
|
|
io_req_set_res(preq, -ECANCELED, 0);
|
|
io_req_task_complete(preq, &ts);
|
|
out:
|
|
io_ring_submit_unlock(ctx, issue_flags);
|
|
if (ret < 0) {
|
|
req_set_fail(req);
|
|
return ret;
|
|
}
|
|
/* complete update request, we're done with it */
|
|
io_req_set_res(req, ret, 0);
|
|
return IOU_OK;
|
|
}
|
|
|
|
void io_apoll_cache_free(struct io_cache_entry *entry)
|
|
{
|
|
kfree(container_of(entry, struct async_poll, cache));
|
|
}
|