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444fe04f7a
linux/drivers/md/dm.c
Ming Lei 444fe04f7a dm: improve BLK_STS_DM_REQUEUE and BLK_STS_AGAIN handling 
If either BLK_STS_DM_REQUEUE or BLK_STS_AGAIN is returned for POLLED
io, we requeue the original bio into deferred list and kick md->wq to
re-submit it to block layer.

Improve the handling in the following way:

1) Factor out dm_handle_requeue() for handling dm_io requeue.

2) Unify handling for BLK_STS_DM_REQUEUE and BLK_STS_AGAIN: clear
   REQ_POLLED for BLK_STS_DM_REQUEUE too, for the sake of simplicity,
   given BLK_STS_DM_REQUEUE is very unusual.

3) Queue md->wq explicitly in dm_handle_requeue(), so requeue handling
   becomes more robust.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
2022-06-29 14:17:16 -04:00

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/*
* Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
* Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
*
* This file is released under the GPL.
*/
#include "dm-core.h"
#include "dm-rq.h"
#include "dm-uevent.h"
#include "dm-ima.h"
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/sched/mm.h>
#include <linux/sched/signal.h>
#include <linux/blkpg.h>
#include <linux/bio.h>
#include <linux/mempool.h>
#include <linux/dax.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <linux/uio.h>
#include <linux/hdreg.h>
#include <linux/delay.h>
#include <linux/wait.h>
#include <linux/pr.h>
#include <linux/refcount.h>
#include <linux/part_stat.h>
#include <linux/blk-crypto.h>
#include <linux/blk-crypto-profile.h>
#define DM_MSG_PREFIX "core"
/*
* Cookies are numeric values sent with CHANGE and REMOVE
* uevents while resuming, removing or renaming the device.
*/
#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
#define DM_COOKIE_LENGTH 24
/*
* For REQ_POLLED fs bio, this flag is set if we link mapped underlying
* dm_io into one list, and reuse bio->bi_private as the list head. Before
* ending this fs bio, we will recover its ->bi_private.
*/
#define REQ_DM_POLL_LIST REQ_DRV
static const char *_name = DM_NAME;
static unsigned int major = 0;
static unsigned int _major = 0;
static DEFINE_IDR(_minor_idr);
static DEFINE_SPINLOCK(_minor_lock);
static void do_deferred_remove(struct work_struct *w);
static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
static struct workqueue_struct *deferred_remove_workqueue;
atomic_t dm_global_event_nr = ATOMIC_INIT(0);
DECLARE_WAIT_QUEUE_HEAD(dm_global_eventq);
void dm_issue_global_event(void)
{
atomic_inc(&dm_global_event_nr);
wake_up(&dm_global_eventq);
}
DEFINE_STATIC_KEY_FALSE(stats_enabled);
DEFINE_STATIC_KEY_FALSE(swap_bios_enabled);
DEFINE_STATIC_KEY_FALSE(zoned_enabled);
/*
* One of these is allocated (on-stack) per original bio.
*/
struct clone_info {
struct dm_table *map;
struct bio *bio;
struct dm_io *io;
sector_t sector;
unsigned sector_count;
bool is_abnormal_io:1;
bool submit_as_polled:1;
};
static inline struct dm_target_io *clone_to_tio(struct bio *clone)
{
return container_of(clone, struct dm_target_io, clone);
}
void *dm_per_bio_data(struct bio *bio, size_t data_size)
{
if (!dm_tio_flagged(clone_to_tio(bio), DM_TIO_INSIDE_DM_IO))
return (char *)bio - DM_TARGET_IO_BIO_OFFSET - data_size;
return (char *)bio - DM_IO_BIO_OFFSET - data_size;
}
EXPORT_SYMBOL_GPL(dm_per_bio_data);
struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
{
struct dm_io *io = (struct dm_io *)((char *)data + data_size);
if (io->magic == DM_IO_MAGIC)
return (struct bio *)((char *)io + DM_IO_BIO_OFFSET);
BUG_ON(io->magic != DM_TIO_MAGIC);
return (struct bio *)((char *)io + DM_TARGET_IO_BIO_OFFSET);
}
EXPORT_SYMBOL_GPL(dm_bio_from_per_bio_data);
unsigned dm_bio_get_target_bio_nr(const struct bio *bio)
{
return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
}
EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr);
#define MINOR_ALLOCED ((void *)-1)
#define DM_NUMA_NODE NUMA_NO_NODE
static int dm_numa_node = DM_NUMA_NODE;
#define DEFAULT_SWAP_BIOS (8 * 1048576 / PAGE_SIZE)
static int swap_bios = DEFAULT_SWAP_BIOS;
static int get_swap_bios(void)
{
int latch = READ_ONCE(swap_bios);
if (unlikely(latch <= 0))
latch = DEFAULT_SWAP_BIOS;
return latch;
}
struct table_device {
struct list_head list;
refcount_t count;
struct dm_dev dm_dev;
};
/*
* Bio-based DM's mempools' reserved IOs set by the user.
*/
#define RESERVED_BIO_BASED_IOS 16
static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
static int __dm_get_module_param_int(int *module_param, int min, int max)
{
int param = READ_ONCE(*module_param);
int modified_param = 0;
bool modified = true;
if (param < min)
modified_param = min;
else if (param > max)
modified_param = max;
else
modified = false;
if (modified) {
(void)cmpxchg(module_param, param, modified_param);
param = modified_param;
}
return param;
}
unsigned __dm_get_module_param(unsigned *module_param,
unsigned def, unsigned max)
{
unsigned param = READ_ONCE(*module_param);
unsigned modified_param = 0;
if (!param)
modified_param = def;
else if (param > max)
modified_param = max;
if (modified_param) {
(void)cmpxchg(module_param, param, modified_param);
param = modified_param;
}
return param;
}
unsigned dm_get_reserved_bio_based_ios(void)
{
return __dm_get_module_param(&reserved_bio_based_ios,
RESERVED_BIO_BASED_IOS, DM_RESERVED_MAX_IOS);
}
EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
static unsigned dm_get_numa_node(void)
{
return __dm_get_module_param_int(&dm_numa_node,
DM_NUMA_NODE, num_online_nodes() - 1);
}
static int __init local_init(void)
{
int r;
r = dm_uevent_init();
if (r)
return r;
deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
if (!deferred_remove_workqueue) {
r = -ENOMEM;
goto out_uevent_exit;
}
_major = major;
r = register_blkdev(_major, _name);
if (r < 0)
goto out_free_workqueue;
if (!_major)
_major = r;
return 0;
out_free_workqueue:
destroy_workqueue(deferred_remove_workqueue);
out_uevent_exit:
dm_uevent_exit();
return r;
}
static void local_exit(void)
{
flush_scheduled_work();
destroy_workqueue(deferred_remove_workqueue);
unregister_blkdev(_major, _name);
dm_uevent_exit();
_major = 0;
DMINFO("cleaned up");
}
static int (*_inits[])(void) __initdata = {
local_init,
dm_target_init,
dm_linear_init,
dm_stripe_init,
dm_io_init,
dm_kcopyd_init,
dm_interface_init,
dm_statistics_init,
};
static void (*_exits[])(void) = {
local_exit,
dm_target_exit,
dm_linear_exit,
dm_stripe_exit,
dm_io_exit,
dm_kcopyd_exit,
dm_interface_exit,
dm_statistics_exit,
};
static int __init dm_init(void)
{
const int count = ARRAY_SIZE(_inits);
int r, i;
#if (IS_ENABLED(CONFIG_IMA) && !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE))
DMWARN("CONFIG_IMA_DISABLE_HTABLE is disabled."
" Duplicate IMA measurements will not be recorded in the IMA log.");
#endif
for (i = 0; i < count; i++) {
r = _inits[i]();
if (r)
goto bad;
}
return 0;
bad:
while (i--)
_exits[i]();
return r;
}
static void __exit dm_exit(void)
{
int i = ARRAY_SIZE(_exits);
while (i--)
_exits[i]();
/*
* Should be empty by this point.
*/
idr_destroy(&_minor_idr);
}
/*
* Block device functions
*/
int dm_deleting_md(struct mapped_device *md)
{
return test_bit(DMF_DELETING, &md->flags);
}
static int dm_blk_open(struct block_device *bdev, fmode_t mode)
{
struct mapped_device *md;
spin_lock(&_minor_lock);
md = bdev->bd_disk->private_data;
if (!md)
goto out;
if (test_bit(DMF_FREEING, &md->flags) ||
dm_deleting_md(md)) {
md = NULL;
goto out;
}
dm_get(md);
atomic_inc(&md->open_count);
out:
spin_unlock(&_minor_lock);
return md ? 0 : -ENXIO;
}
static void dm_blk_close(struct gendisk *disk, fmode_t mode)
{
struct mapped_device *md;
spin_lock(&_minor_lock);
md = disk->private_data;
if (WARN_ON(!md))
goto out;
if (atomic_dec_and_test(&md->open_count) &&
(test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
queue_work(deferred_remove_workqueue, &deferred_remove_work);
dm_put(md);
out:
spin_unlock(&_minor_lock);
}
int dm_open_count(struct mapped_device *md)
{
return atomic_read(&md->open_count);
}
/*
* Guarantees nothing is using the device before it's deleted.
*/
int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
{
int r = 0;
spin_lock(&_minor_lock);
if (dm_open_count(md)) {
r = -EBUSY;
if (mark_deferred)
set_bit(DMF_DEFERRED_REMOVE, &md->flags);
} else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
r = -EEXIST;
else
set_bit(DMF_DELETING, &md->flags);
spin_unlock(&_minor_lock);
return r;
}
int dm_cancel_deferred_remove(struct mapped_device *md)
{
int r = 0;
spin_lock(&_minor_lock);
if (test_bit(DMF_DELETING, &md->flags))
r = -EBUSY;
else
clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
spin_unlock(&_minor_lock);
return r;
}
static void do_deferred_remove(struct work_struct *w)
{
dm_deferred_remove();
}
static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
struct mapped_device *md = bdev->bd_disk->private_data;
return dm_get_geometry(md, geo);
}
static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
struct block_device **bdev)
{
struct dm_target *tgt;
struct dm_table *map;
int r;
retry:
r = -ENOTTY;
map = dm_get_live_table(md, srcu_idx);
if (!map || !dm_table_get_size(map))
return r;
/* We only support devices that have a single target */
if (dm_table_get_num_targets(map) != 1)
return r;
tgt = dm_table_get_target(map, 0);
if (!tgt->type->prepare_ioctl)
return r;
if (dm_suspended_md(md))
return -EAGAIN;
r = tgt->type->prepare_ioctl(tgt, bdev);
if (r == -ENOTCONN && !fatal_signal_pending(current)) {
dm_put_live_table(md, *srcu_idx);
msleep(10);
goto retry;
}
return r;
}
static void dm_unprepare_ioctl(struct mapped_device *md, int srcu_idx)
{
dm_put_live_table(md, srcu_idx);
}
static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
unsigned int cmd, unsigned long arg)
{
struct mapped_device *md = bdev->bd_disk->private_data;
int r, srcu_idx;
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
if (r < 0)
goto out;
if (r > 0) {
/*
* Target determined this ioctl is being issued against a
* subset of the parent bdev; require extra privileges.
*/
if (!capable(CAP_SYS_RAWIO)) {
DMDEBUG_LIMIT(
"%s: sending ioctl %x to DM device without required privilege.",
current->comm, cmd);
r = -ENOIOCTLCMD;
goto out;
}
}
if (!bdev->bd_disk->fops->ioctl)
r = -ENOTTY;
else
r = bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
out:
dm_unprepare_ioctl(md, srcu_idx);
return r;
}
u64 dm_start_time_ns_from_clone(struct bio *bio)
{
return jiffies_to_nsecs(clone_to_tio(bio)->io->start_time);
}
EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone);
static bool bio_is_flush_with_data(struct bio *bio)
{
return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size);
}
static void dm_io_acct(struct dm_io *io, bool end)
{
struct dm_stats_aux *stats_aux = &io->stats_aux;
unsigned long start_time = io->start_time;
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
unsigned int sectors;
/*
* If REQ_PREFLUSH set, don't account payload, it will be
* submitted (and accounted) after this flush completes.
*/
if (bio_is_flush_with_data(bio))
sectors = 0;
else if (likely(!(dm_io_flagged(io, DM_IO_WAS_SPLIT))))
sectors = bio_sectors(bio);
else
sectors = io->sectors;
if (!end)
bdev_start_io_acct(bio->bi_bdev, sectors, bio_op(bio),
start_time);
else
bdev_end_io_acct(bio->bi_bdev, bio_op(bio), start_time);
if (static_branch_unlikely(&stats_enabled) &&
unlikely(dm_stats_used(&md->stats))) {
sector_t sector;
if (likely(!dm_io_flagged(io, DM_IO_WAS_SPLIT)))
sector = bio->bi_iter.bi_sector;
else
sector = bio_end_sector(bio) - io->sector_offset;
dm_stats_account_io(&md->stats, bio_data_dir(bio),
sector, sectors,
end, start_time, stats_aux);
}
}
static void __dm_start_io_acct(struct dm_io *io)
{
dm_io_acct(io, false);
}
static void dm_start_io_acct(struct dm_io *io, struct bio *clone)
{
/*
* Ensure IO accounting is only ever started once.
*/
if (dm_io_flagged(io, DM_IO_ACCOUNTED))
return;
/* Expect no possibility for race unless DM_TIO_IS_DUPLICATE_BIO. */
if (!clone || likely(dm_tio_is_normal(clone_to_tio(clone)))) {
dm_io_set_flag(io, DM_IO_ACCOUNTED);
} else {
unsigned long flags;
/* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */
spin_lock_irqsave(&io->lock, flags);
if (dm_io_flagged(io, DM_IO_ACCOUNTED)) {
spin_unlock_irqrestore(&io->lock, flags);
return;
}
dm_io_set_flag(io, DM_IO_ACCOUNTED);
spin_unlock_irqrestore(&io->lock, flags);
}
__dm_start_io_acct(io);
}
static void dm_end_io_acct(struct dm_io *io)
{
dm_io_acct(io, true);
}
static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)
{
struct dm_io *io;
struct dm_target_io *tio;
struct bio *clone;
clone = bio_alloc_clone(NULL, bio, GFP_NOIO, &md->mempools->io_bs);
/* Set default bdev, but target must bio_set_dev() before issuing IO */
clone->bi_bdev = md->disk->part0;
tio = clone_to_tio(clone);
tio->flags = 0;
dm_tio_set_flag(tio, DM_TIO_INSIDE_DM_IO);
tio->io = NULL;
io = container_of(tio, struct dm_io, tio);
io->magic = DM_IO_MAGIC;
io->status = BLK_STS_OK;
/* one ref is for submission, the other is for completion */
atomic_set(&io->io_count, 2);
this_cpu_inc(*md->pending_io);
io->orig_bio = bio;
io->split_bio = NULL;
io->md = md;
spin_lock_init(&io->lock);
io->start_time = jiffies;
io->flags = 0;
if (static_branch_unlikely(&stats_enabled))
dm_stats_record_start(&md->stats, &io->stats_aux);
return io;
}
static void free_io(struct dm_io *io)
{
bio_put(&io->tio.clone);
}
static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
unsigned target_bio_nr, unsigned *len, gfp_t gfp_mask)
{
struct dm_target_io *tio;
struct bio *clone;
if (!ci->io->tio.io) {
/* the dm_target_io embedded in ci->io is available */
tio = &ci->io->tio;
/* alloc_io() already initialized embedded clone */
clone = &tio->clone;
} else {
struct mapped_device *md = ci->io->md;
clone = bio_alloc_clone(NULL, ci->bio, gfp_mask,
&md->mempools->bs);
if (!clone)
return NULL;
/* Set default bdev, but target must bio_set_dev() before issuing IO */
clone->bi_bdev = md->disk->part0;
/* REQ_DM_POLL_LIST shouldn't be inherited */
clone->bi_opf &= ~REQ_DM_POLL_LIST;
tio = clone_to_tio(clone);
tio->flags = 0; /* also clears DM_TIO_INSIDE_DM_IO */
}
tio->magic = DM_TIO_MAGIC;
tio->io = ci->io;
tio->ti = ti;
tio->target_bio_nr = target_bio_nr;
tio->len_ptr = len;
tio->old_sector = 0;
if (len) {
clone->bi_iter.bi_size = to_bytes(*len);
if (bio_integrity(clone))
bio_integrity_trim(clone);
}
return clone;
}
static void free_tio(struct bio *clone)
{
if (dm_tio_flagged(clone_to_tio(clone), DM_TIO_INSIDE_DM_IO))
return;
bio_put(clone);
}
/*
* Add the bio to the list of deferred io.
*/
static void queue_io(struct mapped_device *md, struct bio *bio)
{
unsigned long flags;
spin_lock_irqsave(&md->deferred_lock, flags);
bio_list_add(&md->deferred, bio);
spin_unlock_irqrestore(&md->deferred_lock, flags);
queue_work(md->wq, &md->work);
}
/*
* Everyone (including functions in this file), should use this
* function to access the md->map field, and make sure they call
* dm_put_live_table() when finished.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md,
int *srcu_idx) __acquires(md->io_barrier)
{
*srcu_idx = srcu_read_lock(&md->io_barrier);
return srcu_dereference(md->map, &md->io_barrier);
}
void dm_put_live_table(struct mapped_device *md,
int srcu_idx) __releases(md->io_barrier)
{
srcu_read_unlock(&md->io_barrier, srcu_idx);
}
void dm_sync_table(struct mapped_device *md)
{
synchronize_srcu(&md->io_barrier);
synchronize_rcu_expedited();
}
/*
* A fast alternative to dm_get_live_table/dm_put_live_table.
* The caller must not block between these two functions.
*/
static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
{
rcu_read_lock();
return rcu_dereference(md->map);
}
static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
{
rcu_read_unlock();
}
static inline struct dm_table *dm_get_live_table_bio(struct mapped_device *md,
int *srcu_idx, unsigned bio_opf)
{
if (bio_opf & REQ_NOWAIT)
return dm_get_live_table_fast(md);
else
return dm_get_live_table(md, srcu_idx);
}
static inline void dm_put_live_table_bio(struct mapped_device *md, int srcu_idx,
unsigned bio_opf)
{
if (bio_opf & REQ_NOWAIT)
dm_put_live_table_fast(md);
else
dm_put_live_table(md, srcu_idx);
}
static char *_dm_claim_ptr = "I belong to device-mapper";
/*
* Open a table device so we can use it as a map destination.
*/
static int open_table_device(struct table_device *td, dev_t dev,
struct mapped_device *md)
{
struct block_device *bdev;
u64 part_off;
int r;
BUG_ON(td->dm_dev.bdev);
bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _dm_claim_ptr);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
r = bd_link_disk_holder(bdev, dm_disk(md));
if (r) {
blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL);
return r;
}
td->dm_dev.bdev = bdev;
td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev, &part_off);
return 0;
}
/*
* Close a table device that we've been using.
*/
static void close_table_device(struct table_device *td, struct mapped_device *md)
{
if (!td->dm_dev.bdev)
return;
bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
put_dax(td->dm_dev.dax_dev);
td->dm_dev.bdev = NULL;
td->dm_dev.dax_dev = NULL;
}
static struct table_device *find_table_device(struct list_head *l, dev_t dev,
fmode_t mode)
{
struct table_device *td;
list_for_each_entry(td, l, list)
if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
return td;
return NULL;
}
int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
struct dm_dev **result)
{
int r;
struct table_device *td;
mutex_lock(&md->table_devices_lock);
td = find_table_device(&md->table_devices, dev, mode);
if (!td) {
td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id);
if (!td) {
mutex_unlock(&md->table_devices_lock);
return -ENOMEM;
}
td->dm_dev.mode = mode;
td->dm_dev.bdev = NULL;
if ((r = open_table_device(td, dev, md))) {
mutex_unlock(&md->table_devices_lock);
kfree(td);
return r;
}
format_dev_t(td->dm_dev.name, dev);
refcount_set(&td->count, 1);
list_add(&td->list, &md->table_devices);
} else {
refcount_inc(&td->count);
}
mutex_unlock(&md->table_devices_lock);
*result = &td->dm_dev;
return 0;
}
void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
{
struct table_device *td = container_of(d, struct table_device, dm_dev);
mutex_lock(&md->table_devices_lock);
if (refcount_dec_and_test(&td->count)) {
close_table_device(td, md);
list_del(&td->list);
kfree(td);
}
mutex_unlock(&md->table_devices_lock);
}
static void free_table_devices(struct list_head *devices)
{
struct list_head *tmp, *next;
list_for_each_safe(tmp, next, devices) {
struct table_device *td = list_entry(tmp, struct table_device, list);
DMWARN("dm_destroy: %s still exists with %d references",
td->dm_dev.name, refcount_read(&td->count));
kfree(td);
}
}
/*
* Get the geometry associated with a dm device
*/
int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
{
*geo = md->geometry;
return 0;
}
/*
* Set the geometry of a device.
*/
int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
{
sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
if (geo->start > sz) {
DMWARN("Start sector is beyond the geometry limits.");
return -EINVAL;
}
md->geometry = *geo;
return 0;
}
static int __noflush_suspending(struct mapped_device *md)
{
return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
}
/*
* Return true if the dm_io's original bio is requeued.
* io->status is updated with error if requeue disallowed.
*/
static bool dm_handle_requeue(struct dm_io *io)
{
struct bio *bio = io->split_bio ? io->split_bio : io->orig_bio;
bool handle_requeue = (io->status == BLK_STS_DM_REQUEUE);
bool handle_polled_eagain = ((io->status == BLK_STS_AGAIN) &&
(bio->bi_opf & REQ_POLLED));
struct mapped_device *md = io->md;
bool requeued = false;
if (handle_requeue || handle_polled_eagain) {
unsigned long flags;
if (bio->bi_opf & REQ_POLLED) {
/*
* Upper layer won't help us poll split bio
* (io->orig_bio may only reflect a subset of the
* pre-split original) so clear REQ_POLLED.
*/
bio_clear_polled(bio);
}
/*
* Target requested pushing back the I/O or
* polled IO hit BLK_STS_AGAIN.
*/
spin_lock_irqsave(&md->deferred_lock, flags);
if ((__noflush_suspending(md) &&
!WARN_ON_ONCE(dm_is_zone_write(md, bio))) ||
handle_polled_eagain) {
bio_list_add_head(&md->deferred, bio);
requeued = true;
} else {
/*
* noflush suspend was interrupted or this is
* a write to a zoned target.
*/
io->status = BLK_STS_IOERR;
}
spin_unlock_irqrestore(&md->deferred_lock, flags);
}
if (requeued)
queue_work(md->wq, &md->work);
return requeued;
}
static void dm_io_complete(struct dm_io *io)
{
struct bio *bio = io->split_bio ? io->split_bio : io->orig_bio;
struct mapped_device *md = io->md;
blk_status_t io_error;
bool requeued;
requeued = dm_handle_requeue(io);
io_error = io->status;
if (dm_io_flagged(io, DM_IO_ACCOUNTED))
dm_end_io_acct(io);
else if (!io_error) {
/*
* Must handle target that DM_MAPIO_SUBMITTED only to
* then bio_endio() rather than dm_submit_bio_remap()
*/
__dm_start_io_acct(io);
dm_end_io_acct(io);
}
free_io(io);
smp_wmb();
this_cpu_dec(*md->pending_io);
/* nudge anyone waiting on suspend queue */
if (unlikely(wq_has_sleeper(&md->wait)))
wake_up(&md->wait);
/* Return early if the original bio was requeued */
if (requeued)
return;
if (bio_is_flush_with_data(bio)) {
/*
* Preflush done for flush with data, reissue
* without REQ_PREFLUSH.
*/
bio->bi_opf &= ~REQ_PREFLUSH;
queue_io(md, bio);
} else {
/* done with normal IO or empty flush */
if (io_error)
bio->bi_status = io_error;
bio_endio(bio);
}
}
/*
* Decrements the number of outstanding ios that a bio has been
* cloned into, completing the original io if necc.
*/
static inline void __dm_io_dec_pending(struct dm_io *io)
{
if (atomic_dec_and_test(&io->io_count))
dm_io_complete(io);
}
static void dm_io_set_error(struct dm_io *io, blk_status_t error)
{
unsigned long flags;
/* Push-back supersedes any I/O errors */
spin_lock_irqsave(&io->lock, flags);
if (!(io->status == BLK_STS_DM_REQUEUE &&
__noflush_suspending(io->md))) {
io->status = error;
}
spin_unlock_irqrestore(&io->lock, flags);
}
static void dm_io_dec_pending(struct dm_io *io, blk_status_t error)
{
if (unlikely(error))
dm_io_set_error(io, error);
__dm_io_dec_pending(io);
}
void disable_discard(struct mapped_device *md)
{
struct queue_limits *limits = dm_get_queue_limits(md);
/* device doesn't really support DISCARD, disable it */
limits->max_discard_sectors = 0;
}
void disable_write_zeroes(struct mapped_device *md)
{
struct queue_limits *limits = dm_get_queue_limits(md);
/* device doesn't really support WRITE ZEROES, disable it */
limits->max_write_zeroes_sectors = 0;
}
static bool swap_bios_limit(struct dm_target *ti, struct bio *bio)
{
return unlikely((bio->bi_opf & REQ_SWAP) != 0) && unlikely(ti->limit_swap_bios);
}
static void clone_endio(struct bio *bio)
{
blk_status_t error = bio->bi_status;
struct dm_target_io *tio = clone_to_tio(bio);
struct dm_target *ti = tio->ti;
dm_endio_fn endio = ti->type->end_io;
struct dm_io *io = tio->io;
struct mapped_device *md = io->md;
if (unlikely(error == BLK_STS_TARGET)) {
if (bio_op(bio) == REQ_OP_DISCARD &&
!bdev_max_discard_sectors(bio->bi_bdev))
disable_discard(md);
else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
!bdev_write_zeroes_sectors(bio->bi_bdev))
disable_write_zeroes(md);
}
if (static_branch_unlikely(&zoned_enabled) &&
unlikely(blk_queue_is_zoned(bdev_get_queue(bio->bi_bdev))))
dm_zone_endio(io, bio);
if (endio) {
int r = endio(ti, bio, &error);
switch (r) {
case DM_ENDIO_REQUEUE:
if (static_branch_unlikely(&zoned_enabled)) {
/*
* Requeuing writes to a sequential zone of a zoned
* target will break the sequential write pattern:
* fail such IO.
*/
if (WARN_ON_ONCE(dm_is_zone_write(md, bio)))
error = BLK_STS_IOERR;
else
error = BLK_STS_DM_REQUEUE;
} else
error = BLK_STS_DM_REQUEUE;
fallthrough;
case DM_ENDIO_DONE:
break;
case DM_ENDIO_INCOMPLETE:
/* The target will handle the io */
return;
default:
DMWARN("unimplemented target endio return value: %d", r);
BUG();
}
}
if (static_branch_unlikely(&swap_bios_enabled) &&
unlikely(swap_bios_limit(ti, bio)))
up(&md->swap_bios_semaphore);
free_tio(bio);
dm_io_dec_pending(io, error);
}
/*
* Return maximum size of I/O possible at the supplied sector up to the current
* target boundary.
*/
static inline sector_t max_io_len_target_boundary(struct dm_target *ti,
sector_t target_offset)
{
return ti->len - target_offset;
}
static sector_t max_io_len(struct dm_target *ti, sector_t sector)
{
sector_t target_offset = dm_target_offset(ti, sector);
sector_t len = max_io_len_target_boundary(ti, target_offset);
/*
* Does the target need to split IO even further?
* - varied (per target) IO splitting is a tenet of DM; this
* explains why stacked chunk_sectors based splitting via
* blk_queue_split() isn't possible here.
*/
if (!ti->max_io_len)
return len;
return min_t(sector_t, len,
min(queue_max_sectors(ti->table->md->queue),
blk_chunk_sectors_left(target_offset, ti->max_io_len)));
}
int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
{
if (len > UINT_MAX) {
DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
(unsigned long long)len, UINT_MAX);
ti->error = "Maximum size of target IO is too large";
return -EINVAL;
}
ti->max_io_len = (uint32_t) len;
return 0;
}
EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
static struct dm_target *dm_dax_get_live_target(struct mapped_device *md,
sector_t sector, int *srcu_idx)
__acquires(md->io_barrier)
{
struct dm_table *map;
struct dm_target *ti;
map = dm_get_live_table(md, srcu_idx);
if (!map)
return NULL;
ti = dm_table_find_target(map, sector);
if (!ti)
return NULL;
return ti;
}
static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
long nr_pages, enum dax_access_mode mode, void **kaddr,
pfn_t *pfn)
{
struct mapped_device *md = dax_get_private(dax_dev);
sector_t sector = pgoff * PAGE_SECTORS;
struct dm_target *ti;
long len, ret = -EIO;
int srcu_idx;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti)
goto out;
if (!ti->type->direct_access)
goto out;
len = max_io_len(ti, sector) / PAGE_SECTORS;
if (len < 1)
goto out;
nr_pages = min(len, nr_pages);
ret = ti->type->direct_access(ti, pgoff, nr_pages, mode, kaddr, pfn);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
size_t nr_pages)
{
struct mapped_device *md = dax_get_private(dax_dev);
sector_t sector = pgoff * PAGE_SECTORS;
struct dm_target *ti;
int ret = -EIO;
int srcu_idx;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti)
goto out;
if (WARN_ON(!ti->type->dax_zero_page_range)) {
/*
* ->zero_page_range() is mandatory dax operation. If we are
* here, something is wrong.
*/
goto out;
}
ret = ti->type->dax_zero_page_range(ti, pgoff, nr_pages);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
static size_t dm_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
void *addr, size_t bytes, struct iov_iter *i)
{
struct mapped_device *md = dax_get_private(dax_dev);
sector_t sector = pgoff * PAGE_SECTORS;
struct dm_target *ti;
int srcu_idx;
long ret = 0;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti || !ti->type->dax_recovery_write)
goto out;
ret = ti->type->dax_recovery_write(ti, pgoff, addr, bytes, i);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
/*
* A target may call dm_accept_partial_bio only from the map routine. It is
* allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management
* operations, REQ_OP_ZONE_APPEND (zone append writes) and any bio serviced by
* __send_duplicate_bios().
*
* dm_accept_partial_bio informs the dm that the target only wants to process
* additional n_sectors sectors of the bio and the rest of the data should be
* sent in a next bio.
*
* A diagram that explains the arithmetics:
* +--------------------+---------------+-------+
* | 1 | 2 | 3 |
* +--------------------+---------------+-------+
*
* <-------------- *tio->len_ptr --------------->
* <----- bio_sectors ----->
* <-- n_sectors -->
*
* Region 1 was already iterated over with bio_advance or similar function.
* (it may be empty if the target doesn't use bio_advance)
* Region 2 is the remaining bio size that the target wants to process.
* (it may be empty if region 1 is non-empty, although there is no reason
* to make it empty)
* The target requires that region 3 is to be sent in the next bio.
*
* If the target wants to receive multiple copies of the bio (via num_*bios, etc),
* the partially processed part (the sum of regions 1+2) must be the same for all
* copies of the bio.
*/
void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
{
struct dm_target_io *tio = clone_to_tio(bio);
unsigned bio_sectors = bio_sectors(bio);
BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
BUG_ON(op_is_zone_mgmt(bio_op(bio)));
BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);
BUG_ON(bio_sectors > *tio->len_ptr);
BUG_ON(n_sectors > bio_sectors);
*tio->len_ptr -= bio_sectors - n_sectors;
bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
/*
* __split_and_process_bio() may have already saved mapped part
* for accounting but it is being reduced so update accordingly.
*/
dm_io_set_flag(tio->io, DM_IO_WAS_SPLIT);
tio->io->sectors = n_sectors;
}
EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
/*
* @clone: clone bio that DM core passed to target's .map function
* @tgt_clone: clone of @clone bio that target needs submitted
*
* Targets should use this interface to submit bios they take
* ownership of when returning DM_MAPIO_SUBMITTED.
*
* Target should also enable ti->accounts_remapped_io
*/
void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
{
struct dm_target_io *tio = clone_to_tio(clone);
struct dm_io *io = tio->io;
/* establish bio that will get submitted */
if (!tgt_clone)
tgt_clone = clone;
/*
* Account io->origin_bio to DM dev on behalf of target
* that took ownership of IO with DM_MAPIO_SUBMITTED.
*/
dm_start_io_acct(io, clone);
trace_block_bio_remap(tgt_clone, disk_devt(io->md->disk),
tio->old_sector);
submit_bio_noacct(tgt_clone);
}
EXPORT_SYMBOL_GPL(dm_submit_bio_remap);
static noinline void __set_swap_bios_limit(struct mapped_device *md, int latch)
{
mutex_lock(&md->swap_bios_lock);
while (latch < md->swap_bios) {
cond_resched();
down(&md->swap_bios_semaphore);
md->swap_bios--;
}
while (latch > md->swap_bios) {
cond_resched();
up(&md->swap_bios_semaphore);
md->swap_bios++;
}
mutex_unlock(&md->swap_bios_lock);
}
static void __map_bio(struct bio *clone)
{
struct dm_target_io *tio = clone_to_tio(clone);
struct dm_target *ti = tio->ti;
struct dm_io *io = tio->io;
struct mapped_device *md = io->md;
int r;
clone->bi_end_io = clone_endio;
/*
* Map the clone.
*/
tio->old_sector = clone->bi_iter.bi_sector;
if (static_branch_unlikely(&swap_bios_enabled) &&
unlikely(swap_bios_limit(ti, clone))) {
int latch = get_swap_bios();
if (unlikely(latch != md->swap_bios))
__set_swap_bios_limit(md, latch);
down(&md->swap_bios_semaphore);
}
if (static_branch_unlikely(&zoned_enabled)) {
/*
* Check if the IO needs a special mapping due to zone append
* emulation on zoned target. In this case, dm_zone_map_bio()
* calls the target map operation.
*/
if (unlikely(dm_emulate_zone_append(md)))
r = dm_zone_map_bio(tio);
else
r = ti->type->map(ti, clone);
} else
r = ti->type->map(ti, clone);
switch (r) {
case DM_MAPIO_SUBMITTED:
/* target has assumed ownership of this io */
if (!ti->accounts_remapped_io)
dm_start_io_acct(io, clone);
break;
case DM_MAPIO_REMAPPED:
dm_submit_bio_remap(clone, NULL);
break;
case DM_MAPIO_KILL:
case DM_MAPIO_REQUEUE:
if (static_branch_unlikely(&swap_bios_enabled) &&
unlikely(swap_bios_limit(ti, clone)))
up(&md->swap_bios_semaphore);
free_tio(clone);
if (r == DM_MAPIO_KILL)
dm_io_dec_pending(io, BLK_STS_IOERR);
else
dm_io_dec_pending(io, BLK_STS_DM_REQUEUE);
break;
default:
DMWARN("unimplemented target map return value: %d", r);
BUG();
}
}
static void setup_split_accounting(struct clone_info *ci, unsigned len)
{
struct dm_io *io = ci->io;
if (ci->sector_count > len) {
/*
* Split needed, save the mapped part for accounting.
* NOTE: dm_accept_partial_bio() will update accordingly.
*/
dm_io_set_flag(io, DM_IO_WAS_SPLIT);
io->sectors = len;
}
if (static_branch_unlikely(&stats_enabled) &&
unlikely(dm_stats_used(&io->md->stats))) {
/*
* Save bi_sector in terms of its offset from end of
* original bio, only needed for DM-stats' benefit.
* - saved regardless of whether split needed so that
* dm_accept_partial_bio() doesn't need to.
*/
io->sector_offset = bio_end_sector(ci->bio) - ci->sector;
}
}
static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
struct dm_target *ti, unsigned num_bios)
{
struct bio *bio;
int try;
for (try = 0; try < 2; try++) {
int bio_nr;
if (try)
mutex_lock(&ci->io->md->table_devices_lock);
for (bio_nr = 0; bio_nr < num_bios; bio_nr++) {
bio = alloc_tio(ci, ti, bio_nr, NULL,
try ? GFP_NOIO : GFP_NOWAIT);
if (!bio)
break;
bio_list_add(blist, bio);
}
if (try)
mutex_unlock(&ci->io->md->table_devices_lock);
if (bio_nr == num_bios)
return;
while ((bio = bio_list_pop(blist)))
free_tio(bio);
}
}
static int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
unsigned num_bios, unsigned *len)
{
struct bio_list blist = BIO_EMPTY_LIST;
struct bio *clone;
int ret = 0;
switch (num_bios) {
case 0:
break;
case 1:
if (len)
setup_split_accounting(ci, *len);
clone = alloc_tio(ci, ti, 0, len, GFP_NOIO);
__map_bio(clone);
ret = 1;
break;
default:
/* dm_accept_partial_bio() is not supported with shared tio->len_ptr */
alloc_multiple_bios(&blist, ci, ti, num_bios);
while ((clone = bio_list_pop(&blist))) {
dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO);
__map_bio(clone);
ret += 1;
}
break;
}
return ret;
}
static void __send_empty_flush(struct clone_info *ci)
{
unsigned target_nr = 0;
struct dm_target *ti;
struct bio flush_bio;
/*
* Use an on-stack bio for this, it's safe since we don't
* need to reference it after submit. It's just used as
* the basis for the clone(s).
*/
bio_init(&flush_bio, ci->io->md->disk->part0, NULL, 0,
REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC);
ci->bio = &flush_bio;
ci->sector_count = 0;
ci->io->tio.clone.bi_iter.bi_size = 0;
while ((ti = dm_table_get_target(ci->map, target_nr++))) {
int bios;
atomic_add(ti->num_flush_bios, &ci->io->io_count);
bios = __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
atomic_sub(ti->num_flush_bios - bios, &ci->io->io_count);
}
/*
* alloc_io() takes one extra reference for submission, so the
* reference won't reach 0 without the following subtraction
*/
atomic_sub(1, &ci->io->io_count);
bio_uninit(ci->bio);
}
static void __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti,
unsigned num_bios)
{
unsigned len;
int bios;
len = min_t(sector_t, ci->sector_count,
max_io_len_target_boundary(ti, dm_target_offset(ti, ci->sector)));
atomic_add(num_bios, &ci->io->io_count);
bios = __send_duplicate_bios(ci, ti, num_bios, &len);
/*
* alloc_io() takes one extra reference for submission, so the
* reference won't reach 0 without the following (+1) subtraction
*/
atomic_sub(num_bios - bios + 1, &ci->io->io_count);
ci->sector += len;
ci->sector_count -= len;
}
static bool is_abnormal_io(struct bio *bio)
{
unsigned int op = bio_op(bio);
if (op != REQ_OP_READ && op != REQ_OP_WRITE && op != REQ_OP_FLUSH) {
switch (op) {
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
case REQ_OP_WRITE_ZEROES:
return true;
default:
break;
}
}
return false;
}
static blk_status_t __process_abnormal_io(struct clone_info *ci,
struct dm_target *ti)
{
unsigned num_bios = 0;
switch (bio_op(ci->bio)) {
case REQ_OP_DISCARD:
num_bios = ti->num_discard_bios;
break;
case REQ_OP_SECURE_ERASE:
num_bios = ti->num_secure_erase_bios;
break;
case REQ_OP_WRITE_ZEROES:
num_bios = ti->num_write_zeroes_bios;
break;
}
/*
* Even though the device advertised support for this type of
* request, that does not mean every target supports it, and
* reconfiguration might also have changed that since the
* check was performed.
*/
if (unlikely(!num_bios))
return BLK_STS_NOTSUPP;
__send_changing_extent_only(ci, ti, num_bios);
return BLK_STS_OK;
}
/*
* Reuse ->bi_private as dm_io list head for storing all dm_io instances
* associated with this bio, and this bio's bi_private needs to be
* stored in dm_io->data before the reuse.
*
* bio->bi_private is owned by fs or upper layer, so block layer won't
* touch it after splitting. Meantime it won't be changed by anyone after
* bio is submitted. So this reuse is safe.
*/
static inline struct dm_io **dm_poll_list_head(struct bio *bio)
{
return (struct dm_io **)&bio->bi_private;
}
static void dm_queue_poll_io(struct bio *bio, struct dm_io *io)
{
struct dm_io **head = dm_poll_list_head(bio);
if (!(bio->bi_opf & REQ_DM_POLL_LIST)) {
bio->bi_opf |= REQ_DM_POLL_LIST;
/*
* Save .bi_private into dm_io, so that we can reuse
* .bi_private as dm_io list head for storing dm_io list
*/
io->data = bio->bi_private;
/* tell block layer to poll for completion */
bio->bi_cookie = ~BLK_QC_T_NONE;
io->next = NULL;
} else {
/*
* bio recursed due to split, reuse original poll list,
* and save bio->bi_private too.
*/
io->data = (*head)->data;
io->next = *head;
}
*head = io;
}
/*
* Select the correct strategy for processing a non-flush bio.
*/
static blk_status_t __split_and_process_bio(struct clone_info *ci)
{
struct bio *clone;
struct dm_target *ti;
unsigned len;
ti = dm_table_find_target(ci->map, ci->sector);
if (unlikely(!ti))
return BLK_STS_IOERR;
if (unlikely((ci->bio->bi_opf & REQ_NOWAIT) != 0) &&
unlikely(!dm_target_supports_nowait(ti->type)))
return BLK_STS_NOTSUPP;
if (unlikely(ci->is_abnormal_io))
return __process_abnormal_io(ci, ti);
/*
* Only support bio polling for normal IO, and the target io is
* exactly inside the dm_io instance (verified in dm_poll_dm_io)
*/
ci->submit_as_polled = ci->bio->bi_opf & REQ_POLLED;
len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);
setup_split_accounting(ci, len);
clone = alloc_tio(ci, ti, 0, &len, GFP_NOIO);
__map_bio(clone);
ci->sector += len;
ci->sector_count -= len;
return BLK_STS_OK;
}
static void init_clone_info(struct clone_info *ci, struct mapped_device *md,
struct dm_table *map, struct bio *bio, bool is_abnormal)
{
ci->map = map;
ci->io = alloc_io(md, bio);
ci->bio = bio;
ci->is_abnormal_io = is_abnormal;
ci->submit_as_polled = false;
ci->sector = bio->bi_iter.bi_sector;
ci->sector_count = bio_sectors(bio);
/* Shouldn't happen but sector_count was being set to 0 so... */
if (static_branch_unlikely(&zoned_enabled) &&
WARN_ON_ONCE(op_is_zone_mgmt(bio_op(bio)) && ci->sector_count))
ci->sector_count = 0;
}
/*
* Entry point to split a bio into clones and submit them to the targets.
*/
static void dm_split_and_process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
struct clone_info ci;
struct dm_io *io;
blk_status_t error = BLK_STS_OK;
bool is_abnormal;
is_abnormal = is_abnormal_io(bio);
if (unlikely(is_abnormal)) {
/*
* Use blk_queue_split() for abnormal IO (e.g. discard, etc)
* otherwise associated queue_limits won't be imposed.
*/
blk_queue_split(&bio);
}
init_clone_info(&ci, md, map, bio, is_abnormal);
io = ci.io;
if (bio->bi_opf & REQ_PREFLUSH) {
__send_empty_flush(&ci);
/* dm_io_complete submits any data associated with flush */
goto out;
}
error = __split_and_process_bio(&ci);
if (error || !ci.sector_count)
goto out;
/*
* Remainder must be passed to submit_bio_noacct() so it gets handled
* *after* bios already submitted have been completely processed.
*/
WARN_ON_ONCE(!dm_io_flagged(io, DM_IO_WAS_SPLIT));
io->split_bio = bio_split(bio, io->sectors, GFP_NOIO,
&md->queue->bio_split);
bio_chain(io->split_bio, bio);
trace_block_split(io->split_bio, bio->bi_iter.bi_sector);
submit_bio_noacct(bio);
out:
/*
* Drop the extra reference count for non-POLLED bio, and hold one
* reference for POLLED bio, which will be released in dm_poll_bio
*
* Add every dm_io instance into the dm_io list head which is stored
* in bio->bi_private, so that dm_poll_bio can poll them all.
*/
if (error || !ci.submit_as_polled) {
/*
* In case of submission failure, the extra reference for
* submitting io isn't consumed yet
*/
if (error)
atomic_dec(&io->io_count);
dm_io_dec_pending(io, error);
} else
dm_queue_poll_io(bio, io);
}
static void dm_submit_bio(struct bio *bio)
{
struct mapped_device *md = bio->bi_bdev->bd_disk->private_data;
int srcu_idx;
struct dm_table *map;
unsigned bio_opf = bio->bi_opf;
map = dm_get_live_table_bio(md, &srcu_idx, bio_opf);
/* If suspended, or map not yet available, queue this IO for later */
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) ||
unlikely(!map)) {
if (bio->bi_opf & REQ_NOWAIT)
bio_wouldblock_error(bio);
else if (bio->bi_opf & REQ_RAHEAD)
bio_io_error(bio);
else
queue_io(md, bio);
goto out;
}
dm_split_and_process_bio(md, map, bio);
out:
dm_put_live_table_bio(md, srcu_idx, bio_opf);
}
static bool dm_poll_dm_io(struct dm_io *io, struct io_comp_batch *iob,
unsigned int flags)
{
WARN_ON_ONCE(!dm_tio_is_normal(&io->tio));
/* don't poll if the mapped io is done */
if (atomic_read(&io->io_count) > 1)
bio_poll(&io->tio.clone, iob, flags);
/* bio_poll holds the last reference */
return atomic_read(&io->io_count) == 1;
}
static int dm_poll_bio(struct bio *bio, struct io_comp_batch *iob,
unsigned int flags)
{
struct dm_io **head = dm_poll_list_head(bio);
struct dm_io *list = *head;
struct dm_io *tmp = NULL;
struct dm_io *curr, *next;
/* Only poll normal bio which was marked as REQ_DM_POLL_LIST */
if (!(bio->bi_opf & REQ_DM_POLL_LIST))
return 0;
WARN_ON_ONCE(!list);
/*
* Restore .bi_private before possibly completing dm_io.
*
* bio_poll() is only possible once @bio has been completely
* submitted via submit_bio_noacct()'s depth-first submission.
* So there is no dm_queue_poll_io() race associated with
* clearing REQ_DM_POLL_LIST here.
*/
bio->bi_opf &= ~REQ_DM_POLL_LIST;
bio->bi_private = list->data;
for (curr = list, next = curr->next; curr; curr = next, next =
curr ? curr->next : NULL) {
if (dm_poll_dm_io(curr, iob, flags)) {
/*
* clone_endio() has already occurred, so no
* error handling is needed here.
*/
__dm_io_dec_pending(curr);
} else {
curr->next = tmp;
tmp = curr;
}
}
/* Not done? */
if (tmp) {
bio->bi_opf |= REQ_DM_POLL_LIST;
/* Reset bio->bi_private to dm_io list head */
*head = tmp;
return 0;
}
return 1;
}
/*-----------------------------------------------------------------
* An IDR is used to keep track of allocated minor numbers.
*---------------------------------------------------------------*/
static void free_minor(int minor)
{
spin_lock(&_minor_lock);
idr_remove(&_minor_idr, minor);
spin_unlock(&_minor_lock);
}
/*
* See if the device with a specific minor # is free.
*/
static int specific_minor(int minor)
{
int r;
if (minor >= (1 << MINORBITS))
return -EINVAL;
idr_preload(GFP_KERNEL);
spin_lock(&_minor_lock);
r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
spin_unlock(&_minor_lock);
idr_preload_end();
if (r < 0)
return r == -ENOSPC ? -EBUSY : r;
return 0;
}
static int next_free_minor(int *minor)
{
int r;
idr_preload(GFP_KERNEL);
spin_lock(&_minor_lock);
r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
spin_unlock(&_minor_lock);
idr_preload_end();
if (r < 0)
return r;
*minor = r;
return 0;
}
static const struct block_device_operations dm_blk_dops;
static const struct block_device_operations dm_rq_blk_dops;
static const struct dax_operations dm_dax_ops;
static void dm_wq_work(struct work_struct *work);
#ifdef CONFIG_BLK_INLINE_ENCRYPTION
static void dm_queue_destroy_crypto_profile(struct request_queue *q)
{
dm_destroy_crypto_profile(q->crypto_profile);
}
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
static inline void dm_queue_destroy_crypto_profile(struct request_queue *q)
{
}
#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */
static void cleanup_mapped_device(struct mapped_device *md)
{
if (md->wq)
destroy_workqueue(md->wq);
dm_free_md_mempools(md->mempools);
if (md->dax_dev) {
dax_remove_host(md->disk);
kill_dax(md->dax_dev);
put_dax(md->dax_dev);
md->dax_dev = NULL;
}
dm_cleanup_zoned_dev(md);
if (md->disk) {
spin_lock(&_minor_lock);
md->disk->private_data = NULL;
spin_unlock(&_minor_lock);
if (dm_get_md_type(md) != DM_TYPE_NONE) {
dm_sysfs_exit(md);
del_gendisk(md->disk);
}
dm_queue_destroy_crypto_profile(md->queue);
put_disk(md->disk);
}
if (md->pending_io) {
free_percpu(md->pending_io);
md->pending_io = NULL;
}
cleanup_srcu_struct(&md->io_barrier);
mutex_destroy(&md->suspend_lock);
mutex_destroy(&md->type_lock);
mutex_destroy(&md->table_devices_lock);
mutex_destroy(&md->swap_bios_lock);
dm_mq_cleanup_mapped_device(md);
}
/*
* Allocate and initialise a blank device with a given minor.
*/
static struct mapped_device *alloc_dev(int minor)
{
int r, numa_node_id = dm_get_numa_node();
struct mapped_device *md;
void *old_md;
md = kvzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id);
if (!md) {
DMWARN("unable to allocate device, out of memory.");
return NULL;
}
if (!try_module_get(THIS_MODULE))
goto bad_module_get;
/* get a minor number for the dev */
if (minor == DM_ANY_MINOR)
r = next_free_minor(&minor);
else
r = specific_minor(minor);
if (r < 0)
goto bad_minor;
r = init_srcu_struct(&md->io_barrier);
if (r < 0)
goto bad_io_barrier;
md->numa_node_id = numa_node_id;
md->init_tio_pdu = false;
md->type = DM_TYPE_NONE;
mutex_init(&md->suspend_lock);
mutex_init(&md->type_lock);
mutex_init(&md->table_devices_lock);
spin_lock_init(&md->deferred_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
atomic_set(&md->event_nr, 0);
atomic_set(&md->uevent_seq, 0);
INIT_LIST_HEAD(&md->uevent_list);
INIT_LIST_HEAD(&md->table_devices);
spin_lock_init(&md->uevent_lock);
/*
* default to bio-based until DM table is loaded and md->type
* established. If request-based table is loaded: blk-mq will
* override accordingly.
*/
md->disk = blk_alloc_disk(md->numa_node_id);
if (!md->disk)
goto bad;
md->queue = md->disk->queue;
init_waitqueue_head(&md->wait);
INIT_WORK(&md->work, dm_wq_work);
init_waitqueue_head(&md->eventq);
init_completion(&md->kobj_holder.completion);
md->swap_bios = get_swap_bios();
sema_init(&md->swap_bios_semaphore, md->swap_bios);
mutex_init(&md->swap_bios_lock);
md->disk->major = _major;
md->disk->first_minor = minor;
md->disk->minors = 1;
md->disk->flags |= GENHD_FL_NO_PART;
md->disk->fops = &dm_blk_dops;
md->disk->queue = md->queue;
md->disk->private_data = md;
sprintf(md->disk->disk_name, "dm-%d", minor);
if (IS_ENABLED(CONFIG_FS_DAX)) {
md->dax_dev = alloc_dax(md, &dm_dax_ops);
if (IS_ERR(md->dax_dev)) {
md->dax_dev = NULL;
goto bad;
}
set_dax_nocache(md->dax_dev);
set_dax_nomc(md->dax_dev);
if (dax_add_host(md->dax_dev, md->disk))
goto bad;
}
format_dev_t(md->name, MKDEV(_major, minor));
md->wq = alloc_workqueue("kdmflush/%s", WQ_MEM_RECLAIM, 0, md->name);
if (!md->wq)
goto bad;
md->pending_io = alloc_percpu(unsigned long);
if (!md->pending_io)
goto bad;
dm_stats_init(&md->stats);
/* Populate the mapping, nobody knows we exist yet */
spin_lock(&_minor_lock);
old_md = idr_replace(&_minor_idr, md, minor);
spin_unlock(&_minor_lock);
BUG_ON(old_md != MINOR_ALLOCED);
return md;
bad:
cleanup_mapped_device(md);
bad_io_barrier:
free_minor(minor);
bad_minor:
module_put(THIS_MODULE);
bad_module_get:
kvfree(md);
return NULL;
}
static void unlock_fs(struct mapped_device *md);
static void free_dev(struct mapped_device *md)
{
int minor = MINOR(disk_devt(md->disk));
unlock_fs(md);
cleanup_mapped_device(md);
free_table_devices(&md->table_devices);
dm_stats_cleanup(&md->stats);
free_minor(minor);
module_put(THIS_MODULE);
kvfree(md);
}
/*
* Bind a table to the device.
*/
static void event_callback(void *context)
{
unsigned long flags;
LIST_HEAD(uevents);
struct mapped_device *md = (struct mapped_device *) context;
spin_lock_irqsave(&md->uevent_lock, flags);
list_splice_init(&md->uevent_list, &uevents);
spin_unlock_irqrestore(&md->uevent_lock, flags);
dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
atomic_inc(&md->event_nr);
wake_up(&md->eventq);
dm_issue_global_event();
}
/*
* Returns old map, which caller must destroy.
*/
static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
struct queue_limits *limits)
{
struct dm_table *old_map;
sector_t size;
int ret;
lockdep_assert_held(&md->suspend_lock);
size = dm_table_get_size(t);
/*
* Wipe any geometry if the size of the table changed.
*/
if (size != dm_get_size(md))
memset(&md->geometry, 0, sizeof(md->geometry));
if (!get_capacity(md->disk))
set_capacity(md->disk, size);
else
set_capacity_and_notify(md->disk, size);
dm_table_event_callback(t, event_callback, md);
if (dm_table_request_based(t)) {
/*
* Leverage the fact that request-based DM targets are
* immutable singletons - used to optimize dm_mq_queue_rq.
*/
md->immutable_target = dm_table_get_immutable_target(t);
/*
* There is no need to reload with request-based dm because the
* size of front_pad doesn't change.
*
* Note for future: If you are to reload bioset, prep-ed
* requests in the queue may refer to bio from the old bioset,
* so you must walk through the queue to unprep.
*/
if (!md->mempools) {
md->mempools = t->mempools;
t->mempools = NULL;
}
} else {
/*
* The md may already have mempools that need changing.
* If so, reload bioset because front_pad may have changed
* because a different table was loaded.
*/
dm_free_md_mempools(md->mempools);
md->mempools = t->mempools;
t->mempools = NULL;
}
ret = dm_table_set_restrictions(t, md->queue, limits);
if (ret) {
old_map = ERR_PTR(ret);
goto out;
}
old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
rcu_assign_pointer(md->map, (void *)t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
if (old_map)
dm_sync_table(md);
out:
return old_map;
}
/*
* Returns unbound table for the caller to free.
*/
static struct dm_table *__unbind(struct mapped_device *md)
{
struct dm_table *map = rcu_dereference_protected(md->map, 1);
if (!map)
return NULL;
dm_table_event_callback(map, NULL, NULL);
RCU_INIT_POINTER(md->map, NULL);
dm_sync_table(md);
return map;
}
/*
* Constructor for a new device.
*/
int dm_create(int minor, struct mapped_device **result)
{
struct mapped_device *md;
md = alloc_dev(minor);
if (!md)
return -ENXIO;
dm_ima_reset_data(md);
*result = md;
return 0;
}
/*
* Functions to manage md->type.
* All are required to hold md->type_lock.
*/
void dm_lock_md_type(struct mapped_device *md)
{
mutex_lock(&md->type_lock);
}
void dm_unlock_md_type(struct mapped_device *md)
{
mutex_unlock(&md->type_lock);
}
void dm_set_md_type(struct mapped_device *md, enum dm_queue_mode type)
{
BUG_ON(!mutex_is_locked(&md->type_lock));
md->type = type;
}
enum dm_queue_mode dm_get_md_type(struct mapped_device *md)
{
return md->type;
}
struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
{
return md->immutable_target_type;
}
/*
* The queue_limits are only valid as long as you have a reference
* count on 'md'.
*/
struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
{
BUG_ON(!atomic_read(&md->holders));
return &md->queue->limits;
}
EXPORT_SYMBOL_GPL(dm_get_queue_limits);
/*
* Setup the DM device's queue based on md's type
*/
int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
{
enum dm_queue_mode type = dm_table_get_type(t);
struct queue_limits limits;
int r;
switch (type) {
case DM_TYPE_REQUEST_BASED:
md->disk->fops = &dm_rq_blk_dops;
r = dm_mq_init_request_queue(md, t);
if (r) {
DMERR("Cannot initialize queue for request-based dm mapped device");
return r;
}
break;
case DM_TYPE_BIO_BASED:
case DM_TYPE_DAX_BIO_BASED:
break;
case DM_TYPE_NONE:
WARN_ON_ONCE(true);
break;
}
r = dm_calculate_queue_limits(t, &limits);
if (r) {
DMERR("Cannot calculate initial queue limits");
return r;
}
r = dm_table_set_restrictions(t, md->queue, &limits);
if (r)
return r;
r = add_disk(md->disk);
if (r)
return r;
r = dm_sysfs_init(md);
if (r) {
del_gendisk(md->disk);
return r;
}
md->type = type;
return 0;
}
struct mapped_device *dm_get_md(dev_t dev)
{
struct mapped_device *md;
unsigned minor = MINOR(dev);
if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
return NULL;
spin_lock(&_minor_lock);
md = idr_find(&_minor_idr, minor);
if (!md || md == MINOR_ALLOCED || (MINOR(disk_devt(dm_disk(md))) != minor) ||
test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
md = NULL;
goto out;
}
dm_get(md);
out:
spin_unlock(&_minor_lock);
return md;
}
EXPORT_SYMBOL_GPL(dm_get_md);
void *dm_get_mdptr(struct mapped_device *md)
{
return md->interface_ptr;
}
void dm_set_mdptr(struct mapped_device *md, void *ptr)
{
md->interface_ptr = ptr;
}
void dm_get(struct mapped_device *md)
{
atomic_inc(&md->holders);
BUG_ON(test_bit(DMF_FREEING, &md->flags));
}
int dm_hold(struct mapped_device *md)
{
spin_lock(&_minor_lock);
if (test_bit(DMF_FREEING, &md->flags)) {
spin_unlock(&_minor_lock);
return -EBUSY;
}
dm_get(md);
spin_unlock(&_minor_lock);
return 0;
}
EXPORT_SYMBOL_GPL(dm_hold);
const char *dm_device_name(struct mapped_device *md)
{
return md->name;
}
EXPORT_SYMBOL_GPL(dm_device_name);
static void __dm_destroy(struct mapped_device *md, bool wait)
{
struct dm_table *map;
int srcu_idx;
might_sleep();
spin_lock(&_minor_lock);
idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
set_bit(DMF_FREEING, &md->flags);
spin_unlock(&_minor_lock);
blk_mark_disk_dead(md->disk);
/*
* Take suspend_lock so that presuspend and postsuspend methods
* do not race with internal suspend.
*/
mutex_lock(&md->suspend_lock);
map = dm_get_live_table(md, &srcu_idx);
if (!dm_suspended_md(md)) {
dm_table_presuspend_targets(map);
set_bit(DMF_SUSPENDED, &md->flags);
set_bit(DMF_POST_SUSPENDING, &md->flags);
dm_table_postsuspend_targets(map);
}
/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
dm_put_live_table(md, srcu_idx);
mutex_unlock(&md->suspend_lock);
/*
* Rare, but there may be I/O requests still going to complete,
* for example. Wait for all references to disappear.
* No one should increment the reference count of the mapped_device,
* after the mapped_device state becomes DMF_FREEING.
*/
if (wait)
while (atomic_read(&md->holders))
msleep(1);
else if (atomic_read(&md->holders))
DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
dm_device_name(md), atomic_read(&md->holders));
dm_table_destroy(__unbind(md));
free_dev(md);
}
void dm_destroy(struct mapped_device *md)
{
__dm_destroy(md, true);
}
void dm_destroy_immediate(struct mapped_device *md)
{
__dm_destroy(md, false);
}
void dm_put(struct mapped_device *md)
{
atomic_dec(&md->holders);
}
EXPORT_SYMBOL_GPL(dm_put);
static bool dm_in_flight_bios(struct mapped_device *md)
{
int cpu;
unsigned long sum = 0;
for_each_possible_cpu(cpu)
sum += *per_cpu_ptr(md->pending_io, cpu);
return sum != 0;
}
static int dm_wait_for_bios_completion(struct mapped_device *md, unsigned int task_state)
{
int r = 0;
DEFINE_WAIT(wait);
while (true) {
prepare_to_wait(&md->wait, &wait, task_state);
if (!dm_in_flight_bios(md))
break;
if (signal_pending_state(task_state, current)) {
r = -EINTR;
break;
}
io_schedule();
}
finish_wait(&md->wait, &wait);
smp_rmb();
return r;
}
static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_state)
{
int r = 0;
if (!queue_is_mq(md->queue))
return dm_wait_for_bios_completion(md, task_state);
while (true) {
if (!blk_mq_queue_inflight(md->queue))
break;
if (signal_pending_state(task_state, current)) {
r = -EINTR;
break;
}
msleep(5);
}
return r;
}
/*
* Process the deferred bios
*/
static void dm_wq_work(struct work_struct *work)
{
struct mapped_device *md = container_of(work, struct mapped_device, work);
struct bio *bio;
while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
spin_lock_irq(&md->deferred_lock);
bio = bio_list_pop(&md->deferred);
spin_unlock_irq(&md->deferred_lock);
if (!bio)
break;
submit_bio_noacct(bio);
}
}
static void dm_queue_flush(struct mapped_device *md)
{
clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
smp_mb__after_atomic();
queue_work(md->wq, &md->work);
}
/*
* Swap in a new table, returning the old one for the caller to destroy.
*/
struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
{
struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
struct queue_limits limits;
int r;
mutex_lock(&md->suspend_lock);
/* device must be suspended */
if (!dm_suspended_md(md))
goto out;
/*
* If the new table has no data devices, retain the existing limits.
* This helps multipath with queue_if_no_path if all paths disappear,
* then new I/O is queued based on these limits, and then some paths
* reappear.
*/
if (dm_table_has_no_data_devices(table)) {
live_map = dm_get_live_table_fast(md);
if (live_map)
limits = md->queue->limits;
dm_put_live_table_fast(md);
}
if (!live_map) {
r = dm_calculate_queue_limits(table, &limits);
if (r) {
map = ERR_PTR(r);
goto out;
}
}
map = __bind(md, table, &limits);
dm_issue_global_event();
out:
mutex_unlock(&md->suspend_lock);
return map;
}
/*
* Functions to lock and unlock any filesystem running on the
* device.
*/
static int lock_fs(struct mapped_device *md)
{
int r;
WARN_ON(test_bit(DMF_FROZEN, &md->flags));
r = freeze_bdev(md->disk->part0);
if (!r)
set_bit(DMF_FROZEN, &md->flags);
return r;
}
static void unlock_fs(struct mapped_device *md)
{
if (!test_bit(DMF_FROZEN, &md->flags))
return;
thaw_bdev(md->disk->part0);
clear_bit(DMF_FROZEN, &md->flags);
}
/*
* @suspend_flags: DM_SUSPEND_LOCKFS_FLAG and/or DM_SUSPEND_NOFLUSH_FLAG
* @task_state: e.g. TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE
* @dmf_suspended_flag: DMF_SUSPENDED or DMF_SUSPENDED_INTERNALLY
*
* If __dm_suspend returns 0, the device is completely quiescent
* now. There is no request-processing activity. All new requests
* are being added to md->deferred list.
*/
static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
unsigned suspend_flags, unsigned int task_state,
int dmf_suspended_flag)
{
bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
int r;
lockdep_assert_held(&md->suspend_lock);
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
* This flag is cleared before dm_suspend returns.
*/
if (noflush)
set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
else
DMDEBUG("%s: suspending with flush", dm_device_name(md));
/*
* This gets reverted if there's an error later and the targets
* provide the .presuspend_undo hook.
*/
dm_table_presuspend_targets(map);
/*
* Flush I/O to the device.
* Any I/O submitted after lock_fs() may not be flushed.
* noflush takes precedence over do_lockfs.
* (lock_fs() flushes I/Os and waits for them to complete.)
*/
if (!noflush && do_lockfs) {
r = lock_fs(md);
if (r) {
dm_table_presuspend_undo_targets(map);
return r;
}
}
/*
* Here we must make sure that no processes are submitting requests
* to target drivers i.e. no one may be executing
* dm_split_and_process_bio from dm_submit_bio.
*
* To get all processes out of dm_split_and_process_bio in dm_submit_bio,
* we take the write lock. To prevent any process from reentering
* dm_split_and_process_bio from dm_submit_bio and quiesce the thread
* (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND and call
* flush_workqueue(md->wq).
*/
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
if (map)
synchronize_srcu(&md->io_barrier);
/*
* Stop md->queue before flushing md->wq in case request-based
* dm defers requests to md->wq from md->queue.
*/
if (dm_request_based(md))
dm_stop_queue(md->queue);
flush_workqueue(md->wq);
/*
* At this point no more requests are entering target request routines.
* We call dm_wait_for_completion to wait for all existing requests
* to finish.
*/
r = dm_wait_for_completion(md, task_state);
if (!r)
set_bit(dmf_suspended_flag, &md->flags);
if (noflush)
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
if (map)
synchronize_srcu(&md->io_barrier);
/* were we interrupted ? */
if (r < 0) {
dm_queue_flush(md);
if (dm_request_based(md))
dm_start_queue(md->queue);
unlock_fs(md);
dm_table_presuspend_undo_targets(map);
/* pushback list is already flushed, so skip flush */
}
return r;
}
/*
* We need to be able to change a mapping table under a mounted
* filesystem. For example we might want to move some data in
* the background. Before the table can be swapped with
* dm_bind_table, dm_suspend must be called to flush any in
* flight bios and ensure that any further io gets deferred.
*/
/*
* Suspend mechanism in request-based dm.
*
* 1. Flush all I/Os by lock_fs() if needed.
* 2. Stop dispatching any I/O by stopping the request_queue.
* 3. Wait for all in-flight I/Os to be completed or requeued.
*
* To abort suspend, start the request_queue.
*/
int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
int r = 0;
retry:
mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
if (dm_suspended_md(md)) {
r = -EINVAL;
goto out_unlock;
}
if (dm_suspended_internally_md(md)) {
/* already internally suspended, wait for internal resume */
mutex_unlock(&md->suspend_lock);
r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
if (r)
return r;
goto retry;
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED);
if (r)
goto out_unlock;
set_bit(DMF_POST_SUSPENDING, &md->flags);
dm_table_postsuspend_targets(map);
clear_bit(DMF_POST_SUSPENDING, &md->flags);
out_unlock:
mutex_unlock(&md->suspend_lock);
return r;
}
static int __dm_resume(struct mapped_device *md, struct dm_table *map)
{
if (map) {
int r = dm_table_resume_targets(map);
if (r)
return r;
}
dm_queue_flush(md);
/*
* Flushing deferred I/Os must be done after targets are resumed
* so that mapping of targets can work correctly.
* Request-based dm is queueing the deferred I/Os in its request_queue.
*/
if (dm_request_based(md))
dm_start_queue(md->queue);
unlock_fs(md);
return 0;
}
int dm_resume(struct mapped_device *md)
{
int r;
struct dm_table *map = NULL;
retry:
r = -EINVAL;
mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
if (!dm_suspended_md(md))
goto out;
if (dm_suspended_internally_md(md)) {
/* already internally suspended, wait for internal resume */
mutex_unlock(&md->suspend_lock);
r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
if (r)
return r;
goto retry;
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
if (!map || !dm_table_get_size(map))
goto out;
r = __dm_resume(md, map);
if (r)
goto out;
clear_bit(DMF_SUSPENDED, &md->flags);
out:
mutex_unlock(&md->suspend_lock);
return r;
}
/*
* Internal suspend/resume works like userspace-driven suspend. It waits
* until all bios finish and prevents issuing new bios to the target drivers.
* It may be used only from the kernel.
*/
static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags)
{
struct dm_table *map = NULL;
lockdep_assert_held(&md->suspend_lock);
if (md->internal_suspend_count++)
return; /* nested internal suspend */
if (dm_suspended_md(md)) {
set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
return; /* nest suspend */
}
map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
/*
* Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
* supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
* would require changing .presuspend to return an error -- avoid this
* until there is a need for more elaborate variants of internal suspend.
*/
(void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE,
DMF_SUSPENDED_INTERNALLY);
set_bit(DMF_POST_SUSPENDING, &md->flags);
dm_table_postsuspend_targets(map);
clear_bit(DMF_POST_SUSPENDING, &md->flags);
}
static void __dm_internal_resume(struct mapped_device *md)
{
BUG_ON(!md->internal_suspend_count);
if (--md->internal_suspend_count)
return; /* resume from nested internal suspend */
if (dm_suspended_md(md))
goto done; /* resume from nested suspend */
/*
* NOTE: existing callers don't need to call dm_table_resume_targets
* (which may fail -- so best to avoid it for now by passing NULL map)
*/
(void) __dm_resume(md, NULL);
done:
clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
smp_mb__after_atomic();
wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
}
void dm_internal_suspend_noflush(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
__dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
void dm_internal_resume(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
__dm_internal_resume(md);
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_resume);
/*
* Fast variants of internal suspend/resume hold md->suspend_lock,
* which prevents interaction with userspace-driven suspend.
*/
void dm_internal_suspend_fast(struct mapped_device *md)
{
mutex_lock(&md->suspend_lock);
if (dm_suspended_md(md) || dm_suspended_internally_md(md))
return;
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
synchronize_srcu(&md->io_barrier);
flush_workqueue(md->wq);
dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
void dm_internal_resume_fast(struct mapped_device *md)
{
if (dm_suspended_md(md) || dm_suspended_internally_md(md))
goto done;
dm_queue_flush(md);
done:
mutex_unlock(&md->suspend_lock);
}
EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
/*-----------------------------------------------------------------
* Event notification.
*---------------------------------------------------------------*/
int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
unsigned cookie)
{
int r;
unsigned noio_flag;
char udev_cookie[DM_COOKIE_LENGTH];
char *envp[] = { udev_cookie, NULL };
noio_flag = memalloc_noio_save();
if (!cookie)
r = kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
else {
snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
DM_COOKIE_ENV_VAR_NAME, cookie);
r = kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
action, envp);
}
memalloc_noio_restore(noio_flag);
return r;
}
uint32_t dm_next_uevent_seq(struct mapped_device *md)
{
return atomic_add_return(1, &md->uevent_seq);
}
uint32_t dm_get_event_nr(struct mapped_device *md)
{
return atomic_read(&md->event_nr);
}
int dm_wait_event(struct mapped_device *md, int event_nr)
{
return wait_event_interruptible(md->eventq,
(event_nr != atomic_read(&md->event_nr)));
}
void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
{
unsigned long flags;
spin_lock_irqsave(&md->uevent_lock, flags);
list_add(elist, &md->uevent_list);
spin_unlock_irqrestore(&md->uevent_lock, flags);
}
/*
* The gendisk is only valid as long as you have a reference
* count on 'md'.
*/
struct gendisk *dm_disk(struct mapped_device *md)
{
return md->disk;
}
EXPORT_SYMBOL_GPL(dm_disk);
struct kobject *dm_kobject(struct mapped_device *md)
{
return &md->kobj_holder.kobj;
}
struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
{
struct mapped_device *md;
md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
spin_lock(&_minor_lock);
if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
md = NULL;
goto out;
}
dm_get(md);
out:
spin_unlock(&_minor_lock);
return md;
}
int dm_suspended_md(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED, &md->flags);
}
static int dm_post_suspending_md(struct mapped_device *md)
{
return test_bit(DMF_POST_SUSPENDING, &md->flags);
}
int dm_suspended_internally_md(struct mapped_device *md)
{
return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
}
int dm_test_deferred_remove_flag(struct mapped_device *md)
{
return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
}
int dm_suspended(struct dm_target *ti)
{
return dm_suspended_md(ti->table->md);
}
EXPORT_SYMBOL_GPL(dm_suspended);
int dm_post_suspending(struct dm_target *ti)
{
return dm_post_suspending_md(ti->table->md);
}
EXPORT_SYMBOL_GPL(dm_post_suspending);
int dm_noflush_suspending(struct dm_target *ti)
{
return __noflush_suspending(ti->table->md);
}
EXPORT_SYMBOL_GPL(dm_noflush_suspending);
void dm_free_md_mempools(struct dm_md_mempools *pools)
{
if (!pools)
return;
bioset_exit(&pools->bs);
bioset_exit(&pools->io_bs);
kfree(pools);
}
struct dm_pr {
u64 old_key;
u64 new_key;
u32 flags;
bool fail_early;
};
static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
void *data)
{
struct mapped_device *md = bdev->bd_disk->private_data;
struct dm_table *table;
struct dm_target *ti;
int ret = -ENOTTY, srcu_idx;
table = dm_get_live_table(md, &srcu_idx);
if (!table || !dm_table_get_size(table))
goto out;
/* We only support devices that have a single target */
if (dm_table_get_num_targets(table) != 1)
goto out;
ti = dm_table_get_target(table, 0);
ret = -EINVAL;
if (!ti->type->iterate_devices)
goto out;
ret = ti->type->iterate_devices(ti, fn, data);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
/*
* For register / unregister we need to manually call out to every path.
*/
static int __dm_pr_register(struct dm_target *ti, struct dm_dev *dev,
sector_t start, sector_t len, void *data)
{
struct dm_pr *pr = data;
const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
if (!ops || !ops->pr_register)
return -EOPNOTSUPP;
return ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
}
static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
u32 flags)
{
struct dm_pr pr = {
.old_key = old_key,
.new_key = new_key,
.flags = flags,
.fail_early = true,
};
int ret;
ret = dm_call_pr(bdev, __dm_pr_register, &pr);
if (ret && new_key) {
/* unregister all paths if we failed to register any path */
pr.old_key = new_key;
pr.new_key = 0;
pr.flags = 0;
pr.fail_early = false;
dm_call_pr(bdev, __dm_pr_register, &pr);
}
return ret;
}
static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
u32 flags)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
int r, srcu_idx;
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
if (r < 0)
goto out;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_reserve)
r = ops->pr_reserve(bdev, key, type, flags);
else
r = -EOPNOTSUPP;
out:
dm_unprepare_ioctl(md, srcu_idx);
return r;
}
static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
int r, srcu_idx;
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
if (r < 0)
goto out;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_release)
r = ops->pr_release(bdev, key, type);
else
r = -EOPNOTSUPP;
out:
dm_unprepare_ioctl(md, srcu_idx);
return r;
}
static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
enum pr_type type, bool abort)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
int r, srcu_idx;
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
if (r < 0)
goto out;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_preempt)
r = ops->pr_preempt(bdev, old_key, new_key, type, abort);
else
r = -EOPNOTSUPP;
out:
dm_unprepare_ioctl(md, srcu_idx);
return r;
}
static int dm_pr_clear(struct block_device *bdev, u64 key)
{
struct mapped_device *md = bdev->bd_disk->private_data;
const struct pr_ops *ops;
int r, srcu_idx;
r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
if (r < 0)
goto out;
ops = bdev->bd_disk->fops->pr_ops;
if (ops && ops->pr_clear)
r = ops->pr_clear(bdev, key);
else
r = -EOPNOTSUPP;
out:
dm_unprepare_ioctl(md, srcu_idx);
return r;
}
static const struct pr_ops dm_pr_ops = {
.pr_register = dm_pr_register,
.pr_reserve = dm_pr_reserve,
.pr_release = dm_pr_release,
.pr_preempt = dm_pr_preempt,
.pr_clear = dm_pr_clear,
};
static const struct block_device_operations dm_blk_dops = {
.submit_bio = dm_submit_bio,
.poll_bio = dm_poll_bio,
.open = dm_blk_open,
.release = dm_blk_close,
.ioctl = dm_blk_ioctl,
.getgeo = dm_blk_getgeo,
.report_zones = dm_blk_report_zones,
.pr_ops = &dm_pr_ops,
.owner = THIS_MODULE
};
static const struct block_device_operations dm_rq_blk_dops = {
.open = dm_blk_open,
.release = dm_blk_close,
.ioctl = dm_blk_ioctl,
.getgeo = dm_blk_getgeo,
.pr_ops = &dm_pr_ops,
.owner = THIS_MODULE
};
static const struct dax_operations dm_dax_ops = {
.direct_access = dm_dax_direct_access,
.zero_page_range = dm_dax_zero_page_range,
.recovery_write = dm_dax_recovery_write,
};
/*
* module hooks
*/
module_init(dm_init);
module_exit(dm_exit);
module_param(major, uint, 0);
MODULE_PARM_DESC(major, "The major number of the device mapper");
module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
module_param(dm_numa_node, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(dm_numa_node, "NUMA node for DM device memory allocations");
module_param(swap_bios, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(swap_bios, "Maximum allowed inflight swap IOs");
MODULE_DESCRIPTION(DM_NAME " driver");
MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
MODULE_LICENSE("GPL");
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