Revision 2bbd00aef0671bfe3c2ca5ba67097246257de125 authored by Johannes Weiner on 26 February 2021, 01:16:47 UTC, committed by Linus Torvalds on 26 February 2021, 17:41:00 UTC
On NOHZ, the periodic vmstat flushers on each CPU can go to sleep and won't wake up until stat changes are detected in the per-cpu deltas of the zone vmstat counters. In commit 75ef71840539 ("mm, vmstat: add infrastructure for per-node vmstats") per-node counters were introduced, and subsequently most stats were moved from the zone to the node level. However, the node counters weren't added to the NOHZ wakeup detection. In theory this can cause per-cpu errors to remain in the user-reported stats indefinitely. In practice this only affects a handful of sub counters (file_mapped, dirty and writeback e.g.) because other page state changes at the node level likely involve a change at the zone level as well (alloc and free, lru ops). Also, nobody has complained. Fix it up for completeness: wake up vmstat refreshing on node changes. Also remove the BUILD_BUG_ONs that assert counter size; we haven't relied on it since we added sizeof() to the range calculation in commit 13c9aaf7fa01 ("mm/vmstat.c: fix NUMA statistics updates"). Link: https://lkml.kernel.org/r/20210202184342.118513-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent a052d4d
dm.c
/*
* 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 <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/keyslot-manager.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
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);
}
/*
* 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;
};
/*
* One of these is allocated per clone bio.
*/
#define DM_TIO_MAGIC 7282014
struct dm_target_io {
unsigned magic;
struct dm_io *io;
struct dm_target *ti;
unsigned target_bio_nr;
unsigned *len_ptr;
bool inside_dm_io;
struct bio clone;
};
/*
* One of these is allocated per original bio.
* It contains the first clone used for that original.
*/
#define DM_IO_MAGIC 5191977
struct dm_io {
unsigned magic;
struct mapped_device *md;
blk_status_t status;
atomic_t io_count;
struct bio *orig_bio;
unsigned long start_time;
spinlock_t endio_lock;
struct dm_stats_aux stats_aux;
/* last member of dm_target_io is 'struct bio' */
struct dm_target_io tio;
};
#define DM_TARGET_IO_BIO_OFFSET (offsetof(struct dm_target_io, clone))
#define DM_IO_BIO_OFFSET \
(offsetof(struct dm_target_io, clone) + offsetof(struct dm_io, tio))
void *dm_per_bio_data(struct bio *bio, size_t data_size)
{
struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
if (!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)
/*
* Bits for the md->flags field.
*/
#define DMF_BLOCK_IO_FOR_SUSPEND 0
#define DMF_SUSPENDED 1
#define DMF_FROZEN 2
#define DMF_FREEING 3
#define DMF_DELETING 4
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_DEFERRED_REMOVE 6
#define DMF_SUSPENDED_INTERNALLY 7
#define DMF_POST_SUSPENDING 8
#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;
}
/*
* For mempools pre-allocation at the table loading time.
*/
struct dm_md_mempools {
struct bio_set bs;
struct bio_set io_bs;
};
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;
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);
}
#ifdef CONFIG_BLK_DEV_ZONED
int dm_report_zones_cb(struct blk_zone *zone, unsigned int idx, void *data)
{
struct dm_report_zones_args *args = data;
sector_t sector_diff = args->tgt->begin - args->start;
/*
* Ignore zones beyond the target range.
*/
if (zone->start >= args->start + args->tgt->len)
return 0;
/*
* Remap the start sector and write pointer position of the zone
* to match its position in the target range.
*/
zone->start += sector_diff;
if (zone->type != BLK_ZONE_TYPE_CONVENTIONAL) {
if (zone->cond == BLK_ZONE_COND_FULL)
zone->wp = zone->start + zone->len;
else if (zone->cond == BLK_ZONE_COND_EMPTY)
zone->wp = zone->start;
else
zone->wp += sector_diff;
}
args->next_sector = zone->start + zone->len;
return args->orig_cb(zone, args->zone_idx++, args->orig_data);
}
EXPORT_SYMBOL_GPL(dm_report_zones_cb);
static int dm_blk_report_zones(struct gendisk *disk, sector_t sector,
unsigned int nr_zones, report_zones_cb cb, void *data)
{
struct mapped_device *md = disk->private_data;
struct dm_table *map;
int srcu_idx, ret;
struct dm_report_zones_args args = {
.next_sector = sector,
.orig_data = data,
.orig_cb = cb,
};
if (dm_suspended_md(md))
return -EAGAIN;
map = dm_get_live_table(md, &srcu_idx);
if (!map) {
ret = -EIO;
goto out;
}
do {
struct dm_target *tgt;
tgt = dm_table_find_target(map, args.next_sector);
if (WARN_ON_ONCE(!tgt->type->report_zones)) {
ret = -EIO;
goto out;
}
args.tgt = tgt;
ret = tgt->type->report_zones(tgt, &args,
nr_zones - args.zone_idx);
if (ret < 0)
goto out;
} while (args.zone_idx < nr_zones &&
args.next_sector < get_capacity(disk));
ret = args.zone_idx;
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
#else
#define dm_blk_report_zones NULL
#endif /* CONFIG_BLK_DEV_ZONED */
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)
{
struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
struct dm_io *io = tio->io;
return jiffies_to_nsecs(io->start_time);
}
EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone);
static void start_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
io->start_time = bio_start_io_acct(bio);
if (unlikely(dm_stats_used(&md->stats)))
dm_stats_account_io(&md->stats, bio_data_dir(bio),
bio->bi_iter.bi_sector, bio_sectors(bio),
false, 0, &io->stats_aux);
}
static void end_io_acct(struct dm_io *io)
{
struct mapped_device *md = io->md;
struct bio *bio = io->orig_bio;
unsigned long duration = jiffies - io->start_time;
bio_end_io_acct(bio, io->start_time);
if (unlikely(dm_stats_used(&md->stats)))
dm_stats_account_io(&md->stats, bio_data_dir(bio),
bio->bi_iter.bi_sector, bio_sectors(bio),
true, duration, &io->stats_aux);
/* nudge anyone waiting on suspend queue */
if (unlikely(wq_has_sleeper(&md->wait)))
wake_up(&md->wait);
}
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_bioset(GFP_NOIO, 0, &md->io_bs);
if (!clone)
return NULL;
tio = container_of(clone, struct dm_target_io, clone);
tio->inside_dm_io = true;
tio->io = NULL;
io = container_of(tio, struct dm_io, tio);
io->magic = DM_IO_MAGIC;
io->status = 0;
atomic_set(&io->io_count, 1);
io->orig_bio = bio;
io->md = md;
spin_lock_init(&io->endio_lock);
start_io_acct(io);
return io;
}
static void free_io(struct mapped_device *md, struct dm_io *io)
{
bio_put(&io->tio.clone);
}
static struct dm_target_io *alloc_tio(struct clone_info *ci, struct dm_target *ti,
unsigned target_bio_nr, gfp_t gfp_mask)
{
struct dm_target_io *tio;
if (!ci->io->tio.io) {
/* the dm_target_io embedded in ci->io is available */
tio = &ci->io->tio;
} else {
struct bio *clone = bio_alloc_bioset(gfp_mask, 0, &ci->io->md->bs);
if (!clone)
return NULL;
tio = container_of(clone, struct dm_target_io, clone);
tio->inside_dm_io = false;
}
tio->magic = DM_TIO_MAGIC;
tio->io = ci->io;
tio->ti = ti;
tio->target_bio_nr = target_bio_nr;
return tio;
}
static void free_tio(struct dm_target_io *tio)
{
if (tio->inside_dm_io)
return;
bio_put(&tio->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 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;
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 = dax_get_by_host(bdev->bd_disk->disk_name);
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;
}
EXPORT_SYMBOL_GPL(dm_get_table_device);
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);
}
EXPORT_SYMBOL(dm_put_table_device);
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);
}
/*
* Decrements the number of outstanding ios that a bio has been
* cloned into, completing the original io if necc.
*/
static void dec_pending(struct dm_io *io, blk_status_t error)
{
unsigned long flags;
blk_status_t io_error;
struct bio *bio;
struct mapped_device *md = io->md;
/* Push-back supersedes any I/O errors */
if (unlikely(error)) {
spin_lock_irqsave(&io->endio_lock, flags);
if (!(io->status == BLK_STS_DM_REQUEUE && __noflush_suspending(md)))
io->status = error;
spin_unlock_irqrestore(&io->endio_lock, flags);
}
if (atomic_dec_and_test(&io->io_count)) {
if (io->status == BLK_STS_DM_REQUEUE) {
/*
* Target requested pushing back the I/O.
*/
spin_lock_irqsave(&md->deferred_lock, flags);
if (__noflush_suspending(md))
/* NOTE early return due to BLK_STS_DM_REQUEUE below */
bio_list_add_head(&md->deferred, io->orig_bio);
else
/* noflush suspend was interrupted. */
io->status = BLK_STS_IOERR;
spin_unlock_irqrestore(&md->deferred_lock, flags);
}
io_error = io->status;
bio = io->orig_bio;
end_io_acct(io);
free_io(md, io);
if (io_error == BLK_STS_DM_REQUEUE)
return;
if ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size) {
/*
* 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);
}
}
}
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;
blk_queue_flag_clear(QUEUE_FLAG_DISCARD, md->queue);
}
void disable_write_same(struct mapped_device *md)
{
struct queue_limits *limits = dm_get_queue_limits(md);
/* device doesn't really support WRITE SAME, disable it */
limits->max_write_same_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 = container_of(bio, struct dm_target_io, clone);
struct dm_io *io = tio->io;
struct mapped_device *md = tio->io->md;
dm_endio_fn endio = tio->ti->type->end_io;
struct bio *orig_bio = io->orig_bio;
struct request_queue *q = bio->bi_bdev->bd_disk->queue;
if (unlikely(error == BLK_STS_TARGET)) {
if (bio_op(bio) == REQ_OP_DISCARD &&
!q->limits.max_discard_sectors)
disable_discard(md);
else if (bio_op(bio) == REQ_OP_WRITE_SAME &&
!q->limits.max_write_same_sectors)
disable_write_same(md);
else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
!q->limits.max_write_zeroes_sectors)
disable_write_zeroes(md);
}
/*
* For zone-append bios get offset in zone of the written
* sector and add that to the original bio sector pos.
*/
if (bio_op(orig_bio) == REQ_OP_ZONE_APPEND) {
sector_t written_sector = bio->bi_iter.bi_sector;
struct request_queue *q = orig_bio->bi_bdev->bd_disk->queue;
u64 mask = (u64)blk_queue_zone_sectors(q) - 1;
orig_bio->bi_iter.bi_sector += written_sector & mask;
}
if (endio) {
int r = endio(tio->ti, bio, &error);
switch (r) {
case DM_ENDIO_REQUEUE:
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 (unlikely(swap_bios_limit(tio->ti, bio))) {
struct mapped_device *md = io->md;
up(&md->swap_bios_semaphore);
}
free_tio(tio);
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);
sector_t max_len;
/*
* 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_max_size_offset() isn't possible here. So pass in
* ti->max_io_len to override stacked chunk_sectors.
*/
if (ti->max_io_len) {
max_len = blk_max_size_offset(ti->table->md->queue,
target_offset, ti->max_io_len);
if (len > max_len)
len = max_len;
}
return 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, 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, kaddr, pfn);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
static bool dm_dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
int blocksize, sector_t start, sector_t len)
{
struct mapped_device *md = dax_get_private(dax_dev);
struct dm_table *map;
bool ret = false;
int srcu_idx;
map = dm_get_live_table(md, &srcu_idx);
if (!map)
goto out;
ret = dm_table_supports_dax(map, device_not_dax_capable, &blocksize);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
static size_t dm_dax_copy_from_iter(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;
long ret = 0;
int srcu_idx;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti)
goto out;
if (!ti->type->dax_copy_from_iter) {
ret = copy_from_iter(addr, bytes, i);
goto out;
}
ret = ti->type->dax_copy_from_iter(ti, pgoff, addr, bytes, i);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
static size_t dm_dax_copy_to_iter(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;
long ret = 0;
int srcu_idx;
ti = dm_dax_get_live_target(md, sector, &srcu_idx);
if (!ti)
goto out;
if (!ti->type->dax_copy_to_iter) {
ret = copy_to_iter(addr, bytes, i);
goto out;
}
ret = ti->type->dax_copy_to_iter(ti, pgoff, addr, bytes, i);
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;
}
/*
* 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_RESET,
* REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH.
*
* 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 --------------->
* <------- bi_size ------->
* <-- 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 = container_of(bio, struct dm_target_io, clone);
unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;
BUG_ON(bio->bi_opf & REQ_PREFLUSH);
BUG_ON(bi_size > *tio->len_ptr);
BUG_ON(n_sectors > bi_size);
*tio->len_ptr -= bi_size - n_sectors;
bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
}
EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
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 blk_qc_t __map_bio(struct dm_target_io *tio)
{
int r;
sector_t sector;
struct bio *clone = &tio->clone;
struct dm_io *io = tio->io;
struct dm_target *ti = tio->ti;
blk_qc_t ret = BLK_QC_T_NONE;
clone->bi_end_io = clone_endio;
/*
* Map the clone. If r == 0 we don't need to do
* anything, the target has assumed ownership of
* this io.
*/
atomic_inc(&io->io_count);
sector = clone->bi_iter.bi_sector;
if (unlikely(swap_bios_limit(ti, clone))) {
struct mapped_device *md = io->md;
int latch = get_swap_bios();
if (unlikely(latch != md->swap_bios))
__set_swap_bios_limit(md, latch);
down(&md->swap_bios_semaphore);
}
r = ti->type->map(ti, clone);
switch (r) {
case DM_MAPIO_SUBMITTED:
break;
case DM_MAPIO_REMAPPED:
/* the bio has been remapped so dispatch it */
trace_block_bio_remap(clone, bio_dev(io->orig_bio), sector);
ret = submit_bio_noacct(clone);
break;
case DM_MAPIO_KILL:
if (unlikely(swap_bios_limit(ti, clone))) {
struct mapped_device *md = io->md;
up(&md->swap_bios_semaphore);
}
free_tio(tio);
dec_pending(io, BLK_STS_IOERR);
break;
case DM_MAPIO_REQUEUE:
if (unlikely(swap_bios_limit(ti, clone))) {
struct mapped_device *md = io->md;
up(&md->swap_bios_semaphore);
}
free_tio(tio);
dec_pending(io, BLK_STS_DM_REQUEUE);
break;
default:
DMWARN("unimplemented target map return value: %d", r);
BUG();
}
return ret;
}
static void bio_setup_sector(struct bio *bio, sector_t sector, unsigned len)
{
bio->bi_iter.bi_sector = sector;
bio->bi_iter.bi_size = to_bytes(len);
}
/*
* Creates a bio that consists of range of complete bvecs.
*/
static int clone_bio(struct dm_target_io *tio, struct bio *bio,
sector_t sector, unsigned len)
{
struct bio *clone = &tio->clone;
int r;
__bio_clone_fast(clone, bio);
r = bio_crypt_clone(clone, bio, GFP_NOIO);
if (r < 0)
return r;
if (bio_integrity(bio)) {
if (unlikely(!dm_target_has_integrity(tio->ti->type) &&
!dm_target_passes_integrity(tio->ti->type))) {
DMWARN("%s: the target %s doesn't support integrity data.",
dm_device_name(tio->io->md),
tio->ti->type->name);
return -EIO;
}
r = bio_integrity_clone(clone, bio, GFP_NOIO);
if (r < 0)
return r;
}
bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
clone->bi_iter.bi_size = to_bytes(len);
if (bio_integrity(bio))
bio_integrity_trim(clone);
return 0;
}
static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
struct dm_target *ti, unsigned num_bios)
{
struct dm_target_io *tio;
int try;
if (!num_bios)
return;
if (num_bios == 1) {
tio = alloc_tio(ci, ti, 0, GFP_NOIO);
bio_list_add(blist, &tio->clone);
return;
}
for (try = 0; try < 2; try++) {
int bio_nr;
struct bio *bio;
if (try)
mutex_lock(&ci->io->md->table_devices_lock);
for (bio_nr = 0; bio_nr < num_bios; bio_nr++) {
tio = alloc_tio(ci, ti, bio_nr, try ? GFP_NOIO : GFP_NOWAIT);
if (!tio)
break;
bio_list_add(blist, &tio->clone);
}
if (try)
mutex_unlock(&ci->io->md->table_devices_lock);
if (bio_nr == num_bios)
return;
while ((bio = bio_list_pop(blist))) {
tio = container_of(bio, struct dm_target_io, clone);
free_tio(tio);
}
}
}
static blk_qc_t __clone_and_map_simple_bio(struct clone_info *ci,
struct dm_target_io *tio, unsigned *len)
{
struct bio *clone = &tio->clone;
tio->len_ptr = len;
__bio_clone_fast(clone, ci->bio);
if (len)
bio_setup_sector(clone, ci->sector, *len);
return __map_bio(tio);
}
static void __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 *bio;
struct dm_target_io *tio;
alloc_multiple_bios(&blist, ci, ti, num_bios);
while ((bio = bio_list_pop(&blist))) {
tio = container_of(bio, struct dm_target_io, clone);
(void) __clone_and_map_simple_bio(ci, tio, len);
}
}
static int __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, NULL, 0);
flush_bio.bi_opf = REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC;
bio_set_dev(&flush_bio, ci->io->md->disk->part0);
ci->bio = &flush_bio;
ci->sector_count = 0;
BUG_ON(bio_has_data(ci->bio));
while ((ti = dm_table_get_target(ci->map, target_nr++)))
__send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
bio_uninit(ci->bio);
return 0;
}
static int __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
sector_t sector, unsigned *len)
{
struct bio *bio = ci->bio;
struct dm_target_io *tio;
int r;
tio = alloc_tio(ci, ti, 0, GFP_NOIO);
tio->len_ptr = len;
r = clone_bio(tio, bio, sector, *len);
if (r < 0) {
free_tio(tio);
return r;
}
(void) __map_bio(tio);
return 0;
}
static int __send_changing_extent_only(struct clone_info *ci, struct dm_target *ti,
unsigned num_bios)
{
unsigned len;
/*
* 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 (!num_bios)
return -EOPNOTSUPP;
len = min_t(sector_t, ci->sector_count,
max_io_len_target_boundary(ti, dm_target_offset(ti, ci->sector)));
__send_duplicate_bios(ci, ti, num_bios, &len);
ci->sector += len;
ci->sector_count -= len;
return 0;
}
static bool is_abnormal_io(struct bio *bio)
{
bool r = false;
switch (bio_op(bio)) {
case REQ_OP_DISCARD:
case REQ_OP_SECURE_ERASE:
case REQ_OP_WRITE_SAME:
case REQ_OP_WRITE_ZEROES:
r = true;
break;
}
return r;
}
static bool __process_abnormal_io(struct clone_info *ci, struct dm_target *ti,
int *result)
{
struct bio *bio = ci->bio;
unsigned num_bios = 0;
switch (bio_op(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_SAME:
num_bios = ti->num_write_same_bios;
break;
case REQ_OP_WRITE_ZEROES:
num_bios = ti->num_write_zeroes_bios;
break;
default:
return false;
}
*result = __send_changing_extent_only(ci, ti, num_bios);
return true;
}
/*
* Select the correct strategy for processing a non-flush bio.
*/
static int __split_and_process_non_flush(struct clone_info *ci)
{
struct dm_target *ti;
unsigned len;
int r;
ti = dm_table_find_target(ci->map, ci->sector);
if (!ti)
return -EIO;
if (__process_abnormal_io(ci, ti, &r))
return r;
len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);
r = __clone_and_map_data_bio(ci, ti, ci->sector, &len);
if (r < 0)
return r;
ci->sector += len;
ci->sector_count -= len;
return 0;
}
static void init_clone_info(struct clone_info *ci, struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
ci->map = map;
ci->io = alloc_io(md, bio);
ci->sector = bio->bi_iter.bi_sector;
}
#define __dm_part_stat_sub(part, field, subnd) \
(part_stat_get(part, field) -= (subnd))
/*
* Entry point to split a bio into clones and submit them to the targets.
*/
static blk_qc_t __split_and_process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
struct clone_info ci;
blk_qc_t ret = BLK_QC_T_NONE;
int error = 0;
init_clone_info(&ci, md, map, bio);
if (bio->bi_opf & REQ_PREFLUSH) {
error = __send_empty_flush(&ci);
/* dec_pending submits any data associated with flush */
} else if (op_is_zone_mgmt(bio_op(bio))) {
ci.bio = bio;
ci.sector_count = 0;
error = __split_and_process_non_flush(&ci);
} else {
ci.bio = bio;
ci.sector_count = bio_sectors(bio);
while (ci.sector_count && !error) {
error = __split_and_process_non_flush(&ci);
if (ci.sector_count && !error) {
/*
* Remainder must be passed to submit_bio_noacct()
* so that it gets handled *after* bios already submitted
* have been completely processed.
* We take a clone of the original to store in
* ci.io->orig_bio to be used by end_io_acct() and
* for dec_pending to use for completion handling.
*/
struct bio *b = bio_split(bio, bio_sectors(bio) - ci.sector_count,
GFP_NOIO, &md->queue->bio_split);
ci.io->orig_bio = b;
/*
* Adjust IO stats for each split, otherwise upon queue
* reentry there will be redundant IO accounting.
* NOTE: this is a stop-gap fix, a proper fix involves
* significant refactoring of DM core's bio splitting
* (by eliminating DM's splitting and just using bio_split)
*/
part_stat_lock();
__dm_part_stat_sub(dm_disk(md)->part0,
sectors[op_stat_group(bio_op(bio))], ci.sector_count);
part_stat_unlock();
bio_chain(b, bio);
trace_block_split(b, bio->bi_iter.bi_sector);
ret = submit_bio_noacct(bio);
break;
}
}
}
/* drop the extra reference count */
dec_pending(ci.io, errno_to_blk_status(error));
return ret;
}
static blk_qc_t dm_submit_bio(struct bio *bio)
{
struct mapped_device *md = bio->bi_bdev->bd_disk->private_data;
blk_qc_t ret = BLK_QC_T_NONE;
int srcu_idx;
struct dm_table *map;
map = dm_get_live_table(md, &srcu_idx);
if (unlikely(!map)) {
DMERR_LIMIT("%s: mapping table unavailable, erroring io",
dm_device_name(md));
bio_io_error(bio);
goto out;
}
/* If suspended, queue this IO for later */
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
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;
}
/*
* Use blk_queue_split() for abnormal IO (e.g. discard, writesame, etc)
* otherwise associated queue_limits won't be imposed.
*/
if (is_abnormal_io(bio))
blk_queue_split(&bio);
ret = __split_and_process_bio(md, map, bio);
out:
dm_put_live_table(md, srcu_idx);
return ret;
}
/*-----------------------------------------------------------------
* 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_keyslot_manager(struct request_queue *q)
{
dm_destroy_keyslot_manager(q->ksm);
}
#else /* CONFIG_BLK_INLINE_ENCRYPTION */
static inline void dm_queue_destroy_keyslot_manager(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);
bioset_exit(&md->bs);
bioset_exit(&md->io_bs);
if (md->dax_dev) {
kill_dax(md->dax_dev);
put_dax(md->dax_dev);
md->dax_dev = NULL;
}
if (md->disk) {
spin_lock(&_minor_lock);
md->disk->private_data = NULL;
spin_unlock(&_minor_lock);
del_gendisk(md->disk);
put_disk(md->disk);
}
if (md->queue) {
dm_queue_destroy_keyslot_manager(md->queue);
blk_cleanup_queue(md->queue);
}
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->queue = blk_alloc_queue(numa_node_id);
if (!md->queue)
goto bad;
md->disk = alloc_disk_node(1, md->numa_node_id);
if (!md->disk)
goto bad;
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->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_DAX_DRIVER)) {
md->dax_dev = alloc_dax(md, md->disk->disk_name,
&dm_dax_ops, 0);
if (IS_ERR(md->dax_dev))
goto bad;
}
add_disk_no_queue_reg(md->disk);
format_dev_t(md->name, MKDEV(_major, minor));
md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
if (!md->wq)
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);
}
static int __bind_mempools(struct mapped_device *md, struct dm_table *t)
{
struct dm_md_mempools *p = dm_table_get_md_mempools(t);
int ret = 0;
if (dm_table_bio_based(t)) {
/*
* 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.
*/
bioset_exit(&md->bs);
bioset_exit(&md->io_bs);
} else if (bioset_initialized(&md->bs)) {
/*
* There's 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.
*/
goto out;
}
BUG_ON(!p ||
bioset_initialized(&md->bs) ||
bioset_initialized(&md->io_bs));
ret = bioset_init_from_src(&md->bs, &p->bs);
if (ret)
goto out;
ret = bioset_init_from_src(&md->io_bs, &p->io_bs);
if (ret)
bioset_exit(&md->bs);
out:
/* mempool bind completed, no longer need any mempools in the table */
dm_table_free_md_mempools(t);
return ret;
}
/*
* 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;
struct request_queue *q = md->queue;
bool request_based = dm_table_request_based(t);
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));
set_capacity_and_notify(md->disk, size);
dm_table_event_callback(t, event_callback, md);
/*
* The queue hasn't been stopped yet, if the old table type wasn't
* for request-based during suspension. So stop it to prevent
* I/O mapping before resume.
* This must be done before setting the queue restrictions,
* because request-based dm may be run just after the setting.
*/
if (request_based)
dm_stop_queue(q);
if (request_based) {
/*
* 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);
}
ret = __bind_mempools(md, t);
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);
dm_table_set_restrictions(t, q, limits);
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)
{
int r;
struct mapped_device *md;
md = alloc_dev(minor);
if (!md)
return -ENXIO;
r = dm_sysfs_init(md);
if (r) {
free_dev(md);
return r;
}
*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)
{
int r;
struct queue_limits limits;
enum dm_queue_mode type = dm_get_md_type(md);
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;
}
dm_table_set_restrictions(t, md->queue, &limits);
blk_register_queue(md->disk);
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_set_queue_dying(md->queue);
/*
* 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_sysfs_exit(md);
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 md_in_flight_bios(struct mapped_device *md)
{
int cpu;
struct block_device *part = dm_disk(md)->part0;
long sum = 0;
for_each_possible_cpu(cpu) {
sum += part_stat_local_read_cpu(part, in_flight[0], cpu);
sum += part_stat_local_read_cpu(part, in_flight[1], cpu);
}
return sum != 0;
}
static int dm_wait_for_bios_completion(struct mapped_device *md, long task_state)
{
int r = 0;
DEFINE_WAIT(wait);
while (true) {
prepare_to_wait(&md->wait, &wait, task_state);
if (!md_in_flight_bios(md))
break;
if (signal_pending_state(task_state, current)) {
r = -EINTR;
break;
}
io_schedule();
}
finish_wait(&md->wait, &wait);
return r;
}
static int dm_wait_for_completion(struct mapped_device *md, long 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, long 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
* __split_and_process_bio from dm_submit_bio.
*
* To get all processes out of __split_and_process_bio in dm_submit_bio,
* we take the write lock. To prevent any process from reentering
* __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);
struct dm_md_mempools *dm_alloc_md_mempools(struct mapped_device *md, enum dm_queue_mode type,
unsigned integrity, unsigned per_io_data_size,
unsigned min_pool_size)
{
struct dm_md_mempools *pools = kzalloc_node(sizeof(*pools), GFP_KERNEL, md->numa_node_id);
unsigned int pool_size = 0;
unsigned int front_pad, io_front_pad;
int ret;
if (!pools)
return NULL;
switch (type) {
case DM_TYPE_BIO_BASED:
case DM_TYPE_DAX_BIO_BASED:
pool_size = max(dm_get_reserved_bio_based_ios(), min_pool_size);
front_pad = roundup(per_io_data_size, __alignof__(struct dm_target_io)) + DM_TARGET_IO_BIO_OFFSET;
io_front_pad = roundup(per_io_data_size, __alignof__(struct dm_io)) + DM_IO_BIO_OFFSET;
ret = bioset_init(&pools->io_bs, pool_size, io_front_pad, 0);
if (ret)
goto out;
if (integrity && bioset_integrity_create(&pools->io_bs, pool_size))
goto out;
break;
case DM_TYPE_REQUEST_BASED:
pool_size = max(dm_get_reserved_rq_based_ios(), min_pool_size);
front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
/* per_io_data_size is used for blk-mq pdu at queue allocation */
break;
default:
BUG();
}
ret = bioset_init(&pools->bs, pool_size, front_pad, 0);
if (ret)
goto out;
if (integrity && bioset_integrity_create(&pools->bs, pool_size))
goto out;
return pools;
out:
dm_free_md_mempools(pools);
return NULL;
}
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,
.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,
.dax_supported = dm_dax_supported,
.copy_from_iter = dm_dax_copy_from_iter,
.copy_to_iter = dm_dax_copy_to_iter,
.zero_page_range = dm_dax_zero_page_range,
};
/*
* 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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