Commit 83d5e5b0 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Alasdair G Kergon

dm: optimize use SRCU and RCU

This patch removes "io_lock" and "map_lock" in struct mapped_device and
"holders" in struct dm_table and replaces these mechanisms with
sleepable-rcu.

Previously, the code would call "dm_get_live_table" and "dm_table_put" to
get and release table. Now, the code is changed to call "dm_get_live_table"
and "dm_put_live_table". dm_get_live_table locks sleepable-rcu and
dm_put_live_table unlocks it.

dm_get_live_table_fast/dm_put_live_table_fast can be used instead of
dm_get_live_table/dm_put_live_table. These *_fast functions use
non-sleepable RCU, so the caller must not block between them.

If the code changes active or inactive dm table, it must call
dm_sync_table before destroying the old table.
Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: default avatarAlasdair G Kergon <agk@redhat.com>
parent 2480945c
......@@ -36,6 +36,14 @@ struct hash_cell {
struct dm_table *new_map;
};
/*
* A dummy definition to make RCU happy.
* struct dm_table should never be dereferenced in this file.
*/
struct dm_table {
int undefined__;
};
struct vers_iter {
size_t param_size;
struct dm_target_versions *vers, *old_vers;
......@@ -242,9 +250,10 @@ static int dm_hash_insert(const char *name, const char *uuid, struct mapped_devi
return -EBUSY;
}
static void __hash_remove(struct hash_cell *hc)
static struct dm_table *__hash_remove(struct hash_cell *hc)
{
struct dm_table *table;
int srcu_idx;
/* remove from the dev hash */
list_del(&hc->uuid_list);
......@@ -253,16 +262,18 @@ static void __hash_remove(struct hash_cell *hc)
dm_set_mdptr(hc->md, NULL);
mutex_unlock(&dm_hash_cells_mutex);
table = dm_get_live_table(hc->md);
if (table) {
table = dm_get_live_table(hc->md, &srcu_idx);
if (table)
dm_table_event(table);
dm_table_put(table);
}
dm_put_live_table(hc->md, srcu_idx);
table = NULL;
if (hc->new_map)
dm_table_destroy(hc->new_map);
table = hc->new_map;
dm_put(hc->md);
free_cell(hc);
return table;
}
static void dm_hash_remove_all(int keep_open_devices)
......@@ -270,6 +281,7 @@ static void dm_hash_remove_all(int keep_open_devices)
int i, dev_skipped;
struct hash_cell *hc;
struct mapped_device *md;
struct dm_table *t;
retry:
dev_skipped = 0;
......@@ -287,10 +299,14 @@ static void dm_hash_remove_all(int keep_open_devices)
continue;
}
__hash_remove(hc);
t = __hash_remove(hc);
up_write(&_hash_lock);
if (t) {
dm_sync_table(md);
dm_table_destroy(t);
}
dm_put(md);
if (likely(keep_open_devices))
dm_destroy(md);
......@@ -356,6 +372,7 @@ static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
struct dm_table *table;
struct mapped_device *md;
unsigned change_uuid = (param->flags & DM_UUID_FLAG) ? 1 : 0;
int srcu_idx;
/*
* duplicate new.
......@@ -418,11 +435,10 @@ static struct mapped_device *dm_hash_rename(struct dm_ioctl *param,
/*
* Wake up any dm event waiters.
*/
table = dm_get_live_table(hc->md);
if (table) {
table = dm_get_live_table(hc->md, &srcu_idx);
if (table)
dm_table_event(table);
dm_table_put(table);
}
dm_put_live_table(hc->md, srcu_idx);
if (!dm_kobject_uevent(hc->md, KOBJ_CHANGE, param->event_nr))
param->flags |= DM_UEVENT_GENERATED_FLAG;
......@@ -620,11 +636,14 @@ static int check_name(const char *name)
* _hash_lock without first calling dm_table_put, because dm_table_destroy
* waits for this dm_table_put and could be called under this lock.
*/
static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
static struct dm_table *dm_get_inactive_table(struct mapped_device *md, int *srcu_idx)
{
struct hash_cell *hc;
struct dm_table *table = NULL;
/* increment rcu count, we don't care about the table pointer */
dm_get_live_table(md, srcu_idx);
down_read(&_hash_lock);
hc = dm_get_mdptr(md);
if (!hc || hc->md != md) {
......@@ -633,8 +652,6 @@ static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
}
table = hc->new_map;
if (table)
dm_table_get(table);
out:
up_read(&_hash_lock);
......@@ -643,10 +660,11 @@ static struct dm_table *dm_get_inactive_table(struct mapped_device *md)
}
static struct dm_table *dm_get_live_or_inactive_table(struct mapped_device *md,
struct dm_ioctl *param)
struct dm_ioctl *param,
int *srcu_idx)
{
return (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) ?
dm_get_inactive_table(md) : dm_get_live_table(md);
dm_get_inactive_table(md, srcu_idx) : dm_get_live_table(md, srcu_idx);
}
/*
......@@ -657,6 +675,7 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
{
struct gendisk *disk = dm_disk(md);
struct dm_table *table;
int srcu_idx;
param->flags &= ~(DM_SUSPEND_FLAG | DM_READONLY_FLAG |
DM_ACTIVE_PRESENT_FLAG);
......@@ -676,26 +695,27 @@ static void __dev_status(struct mapped_device *md, struct dm_ioctl *param)
param->event_nr = dm_get_event_nr(md);
param->target_count = 0;
table = dm_get_live_table(md);
table = dm_get_live_table(md, &srcu_idx);
if (table) {
if (!(param->flags & DM_QUERY_INACTIVE_TABLE_FLAG)) {
if (get_disk_ro(disk))
param->flags |= DM_READONLY_FLAG;
param->target_count = dm_table_get_num_targets(table);
}
dm_table_put(table);
param->flags |= DM_ACTIVE_PRESENT_FLAG;
}
dm_put_live_table(md, srcu_idx);
if (param->flags & DM_QUERY_INACTIVE_TABLE_FLAG) {
table = dm_get_inactive_table(md);
int srcu_idx;
table = dm_get_inactive_table(md, &srcu_idx);
if (table) {
if (!(dm_table_get_mode(table) & FMODE_WRITE))
param->flags |= DM_READONLY_FLAG;
param->target_count = dm_table_get_num_targets(table);
dm_table_put(table);
}
dm_put_live_table(md, srcu_idx);
}
}
......@@ -796,6 +816,7 @@ static int dev_remove(struct dm_ioctl *param, size_t param_size)
struct hash_cell *hc;
struct mapped_device *md;
int r;
struct dm_table *t;
down_write(&_hash_lock);
hc = __find_device_hash_cell(param);
......@@ -819,9 +840,14 @@ static int dev_remove(struct dm_ioctl *param, size_t param_size)
return r;
}
__hash_remove(hc);
t = __hash_remove(hc);
up_write(&_hash_lock);
if (t) {
dm_sync_table(md);
dm_table_destroy(t);
}
if (!dm_kobject_uevent(md, KOBJ_REMOVE, param->event_nr))
param->flags |= DM_UEVENT_GENERATED_FLAG;
......@@ -986,6 +1012,7 @@ static int do_resume(struct dm_ioctl *param)
old_map = dm_swap_table(md, new_map);
if (IS_ERR(old_map)) {
dm_sync_table(md);
dm_table_destroy(new_map);
dm_put(md);
return PTR_ERR(old_map);
......@@ -1003,6 +1030,10 @@ static int do_resume(struct dm_ioctl *param)
param->flags |= DM_UEVENT_GENERATED_FLAG;
}
/*
* Since dm_swap_table synchronizes RCU, nobody should be in
* read-side critical section already.
*/
if (old_map)
dm_table_destroy(old_map);
......@@ -1125,6 +1156,7 @@ static int dev_wait(struct dm_ioctl *param, size_t param_size)
int r = 0;
struct mapped_device *md;
struct dm_table *table;
int srcu_idx;
md = find_device(param);
if (!md)
......@@ -1145,11 +1177,10 @@ static int dev_wait(struct dm_ioctl *param, size_t param_size)
*/
__dev_status(md, param);
table = dm_get_live_or_inactive_table(md, param);
if (table) {
table = dm_get_live_or_inactive_table(md, param, &srcu_idx);
if (table)
retrieve_status(table, param, param_size);
dm_table_put(table);
}
dm_put_live_table(md, srcu_idx);
out:
dm_put(md);
......@@ -1221,7 +1252,7 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
{
int r;
struct hash_cell *hc;
struct dm_table *t;
struct dm_table *t, *old_map = NULL;
struct mapped_device *md;
struct target_type *immutable_target_type;
......@@ -1277,14 +1308,14 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
hc = dm_get_mdptr(md);
if (!hc || hc->md != md) {
DMWARN("device has been removed from the dev hash table.");
dm_table_destroy(t);
up_write(&_hash_lock);
dm_table_destroy(t);
r = -ENXIO;
goto out;
}
if (hc->new_map)
dm_table_destroy(hc->new_map);
old_map = hc->new_map;
hc->new_map = t;
up_write(&_hash_lock);
......@@ -1292,6 +1323,11 @@ static int table_load(struct dm_ioctl *param, size_t param_size)
__dev_status(md, param);
out:
if (old_map) {
dm_sync_table(md);
dm_table_destroy(old_map);
}
dm_put(md);
return r;
......@@ -1301,6 +1337,7 @@ static int table_clear(struct dm_ioctl *param, size_t param_size)
{
struct hash_cell *hc;
struct mapped_device *md;
struct dm_table *old_map = NULL;
down_write(&_hash_lock);
......@@ -1312,7 +1349,7 @@ static int table_clear(struct dm_ioctl *param, size_t param_size)
}
if (hc->new_map) {
dm_table_destroy(hc->new_map);
old_map = hc->new_map;
hc->new_map = NULL;
}
......@@ -1321,6 +1358,10 @@ static int table_clear(struct dm_ioctl *param, size_t param_size)
__dev_status(hc->md, param);
md = hc->md;
up_write(&_hash_lock);
if (old_map) {
dm_sync_table(md);
dm_table_destroy(old_map);
}
dm_put(md);
return 0;
......@@ -1370,6 +1411,7 @@ static int table_deps(struct dm_ioctl *param, size_t param_size)
{
struct mapped_device *md;
struct dm_table *table;
int srcu_idx;
md = find_device(param);
if (!md)
......@@ -1377,11 +1419,10 @@ static int table_deps(struct dm_ioctl *param, size_t param_size)
__dev_status(md, param);
table = dm_get_live_or_inactive_table(md, param);
if (table) {
table = dm_get_live_or_inactive_table(md, param, &srcu_idx);
if (table)
retrieve_deps(table, param, param_size);
dm_table_put(table);
}
dm_put_live_table(md, srcu_idx);
dm_put(md);
......@@ -1396,6 +1437,7 @@ static int table_status(struct dm_ioctl *param, size_t param_size)
{
struct mapped_device *md;
struct dm_table *table;
int srcu_idx;
md = find_device(param);
if (!md)
......@@ -1403,11 +1445,10 @@ static int table_status(struct dm_ioctl *param, size_t param_size)
__dev_status(md, param);
table = dm_get_live_or_inactive_table(md, param);
if (table) {
table = dm_get_live_or_inactive_table(md, param, &srcu_idx);
if (table)
retrieve_status(table, param, param_size);
dm_table_put(table);
}
dm_put_live_table(md, srcu_idx);
dm_put(md);
......@@ -1443,6 +1484,7 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
struct dm_target_msg *tmsg = (void *) param + param->data_start;
size_t maxlen;
char *result = get_result_buffer(param, param_size, &maxlen);
int srcu_idx;
md = find_device(param);
if (!md)
......@@ -1470,9 +1512,9 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
if (r <= 1)
goto out_argv;
table = dm_get_live_table(md);
table = dm_get_live_table(md, &srcu_idx);
if (!table)
goto out_argv;
goto out_table;
if (dm_deleting_md(md)) {
r = -ENXIO;
......@@ -1491,7 +1533,7 @@ static int target_message(struct dm_ioctl *param, size_t param_size)
}
out_table:
dm_table_put(table);
dm_put_live_table(md, srcu_idx);
out_argv:
kfree(argv);
out:
......
......@@ -26,22 +26,8 @@
#define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
#define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
/*
* The table has always exactly one reference from either mapped_device->map
* or hash_cell->new_map. This reference is not counted in table->holders.
* A pair of dm_create_table/dm_destroy_table functions is used for table
* creation/destruction.
*
* Temporary references from the other code increase table->holders. A pair
* of dm_table_get/dm_table_put functions is used to manipulate it.
*
* When the table is about to be destroyed, we wait for table->holders to
* drop to zero.
*/
struct dm_table {
struct mapped_device *md;
atomic_t holders;
unsigned type;
/* btree table */
......@@ -208,7 +194,6 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
INIT_LIST_HEAD(&t->devices);
INIT_LIST_HEAD(&t->target_callbacks);
atomic_set(&t->holders, 0);
if (!num_targets)
num_targets = KEYS_PER_NODE;
......@@ -246,10 +231,6 @@ void dm_table_destroy(struct dm_table *t)
if (!t)
return;
while (atomic_read(&t->holders))
msleep(1);
smp_mb();
/* free the indexes */
if (t->depth >= 2)
vfree(t->index[t->depth - 2]);
......@@ -274,22 +255,6 @@ void dm_table_destroy(struct dm_table *t)
kfree(t);
}
void dm_table_get(struct dm_table *t)
{
atomic_inc(&t->holders);
}
EXPORT_SYMBOL(dm_table_get);
void dm_table_put(struct dm_table *t)
{
if (!t)
return;
smp_mb__before_atomic_dec();
atomic_dec(&t->holders);
}
EXPORT_SYMBOL(dm_table_put);
/*
* Checks to see if we need to extend highs or targets.
*/
......
......@@ -116,13 +116,20 @@ EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
#define DMF_NOFLUSH_SUSPENDING 5
#define DMF_MERGE_IS_OPTIONAL 6
/*
* A dummy definition to make RCU happy.
* struct dm_table should never be dereferenced in this file.
*/
struct dm_table {
int undefined__;
};
/*
* Work processed by per-device workqueue.
*/
struct mapped_device {
struct rw_semaphore io_lock;
struct srcu_struct io_barrier;
struct mutex suspend_lock;
rwlock_t map_lock;
atomic_t holders;
atomic_t open_count;
......@@ -156,6 +163,8 @@ struct mapped_device {
/*
* The current mapping.
* Use dm_get_live_table{_fast} or take suspend_lock for
* dereference.
*/
struct dm_table *map;
......@@ -386,12 +395,14 @@ 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 srcu_idx;
struct dm_table *map;
struct dm_target *tgt;
int r = -ENOTTY;
retry:
map = dm_get_live_table(md);
map = dm_get_live_table(md, &srcu_idx);
if (!map || !dm_table_get_size(map))
goto out;
......@@ -410,7 +421,7 @@ static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
r = tgt->type->ioctl(tgt, cmd, arg);
out:
dm_table_put(map);
dm_put_live_table(md, srcu_idx);
if (r == -ENOTCONN) {
msleep(10);
......@@ -509,20 +520,39 @@ static void queue_io(struct mapped_device *md, struct bio *bio)
/*
* Everyone (including functions in this file), should use this
* function to access the md->map field, and make sure they call
* dm_table_put() when finished.
* dm_put_live_table() when finished.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md)
struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx) __acquires(md->io_barrier)
{
struct dm_table *t;
unsigned long flags;
*srcu_idx = srcu_read_lock(&md->io_barrier);
return srcu_dereference(md->map, &md->io_barrier);
}
read_lock_irqsave(&md->map_lock, flags);
t = md->map;
if (t)
dm_table_get(t);
read_unlock_irqrestore(&md->map_lock, flags);
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);
}
return t;
static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
{
rcu_read_unlock();
}
/*
......@@ -1356,17 +1386,18 @@ static int __split_and_process_non_flush(struct clone_info *ci)
/*
* Entry point to split a bio into clones and submit them to the targets.
*/
static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
static void __split_and_process_bio(struct mapped_device *md,
struct dm_table *map, struct bio *bio)
{
struct clone_info ci;
int error = 0;
ci.map = dm_get_live_table(md);
if (unlikely(!ci.map)) {
if (unlikely(!map)) {
bio_io_error(bio);
return;
}
ci.map = map;
ci.md = md;
ci.io = alloc_io(md);
ci.io->error = 0;
......@@ -1393,7 +1424,6 @@ static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
/* drop the extra reference count */
dec_pending(ci.io, error);
dm_table_put(ci.map);
}
/*-----------------------------------------------------------------
* CRUD END
......@@ -1404,7 +1434,7 @@ static int dm_merge_bvec(struct request_queue *q,
struct bio_vec *biovec)
{
struct mapped_device *md = q->queuedata;
struct dm_table *map = dm_get_live_table(md);
struct dm_table *map = dm_get_live_table_fast(md);
struct dm_target *ti;
sector_t max_sectors;
int max_size = 0;
......@@ -1414,7 +1444,7 @@ static int dm_merge_bvec(struct request_queue *q,
ti = dm_table_find_target(map, bvm->bi_sector);
if (!dm_target_is_valid(ti))
goto out_table;
goto out;
/*
* Find maximum amount of I/O that won't need splitting
......@@ -1443,10 +1473,8 @@ static int dm_merge_bvec(struct request_queue *q,
max_size = 0;
out_table:
dm_table_put(map);
out:
dm_put_live_table_fast(md);
/*
* Always allow an entire first page
*/
......@@ -1465,8 +1493,10 @@ static void _dm_request(struct request_queue *q, struct bio *bio)
int rw = bio_data_dir(bio);
struct mapped_device *md = q->queuedata;
int cpu;
int srcu_idx;
struct dm_table *map;
down_read(&md->io_lock);
map = dm_get_live_table(md, &srcu_idx);
cpu = part_stat_lock();
part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
......@@ -1475,7 +1505,7 @@ static void _dm_request(struct request_queue *q, struct bio *bio)
/* if we're suspended, we have to queue this io for later */
if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
up_read(&md->io_lock);
dm_put_live_table(md, srcu_idx);
if (bio_rw(bio) != READA)
queue_io(md, bio);
......@@ -1484,8 +1514,8 @@ static void _dm_request(struct request_queue *q, struct bio *bio)
return;
}
__split_and_process_bio(md, bio);
up_read(&md->io_lock);
__split_and_process_bio(md, map, bio);
dm_put_live_table(md, srcu_idx);
return;
}
......@@ -1671,7 +1701,8 @@ static struct request *dm_start_request(struct mapped_device *md, struct request
static void dm_request_fn(struct request_queue *q)
{
struct mapped_device *md = q->queuedata;
struct dm_table *map = dm_get_live_table(md);
int srcu_idx;
struct dm_table *map = dm_get_live_table(md, &srcu_idx);
struct dm_target *ti;
struct request *rq, *clone;
sector_t pos;
......@@ -1726,7 +1757,7 @@ static void dm_request_fn(struct request_queue *q)
delay_and_out:
blk_delay_queue(q, HZ / 10);
out:
dm_table_put(map);
dm_put_live_table(md, srcu_idx);
}
int dm_underlying_device_busy(struct request_queue *q)
......@@ -1739,14 +1770,14 @@ static int dm_lld_busy(struct request_queue *q)
{
int r;
struct mapped_device *md = q->queuedata;
struct dm_table *map = dm_get_live_table(md);
struct dm_table *map = dm_get_live_table_fast(md);
if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
r = 1;
else
r = dm_table_any_busy_target(map);
dm_table_put(map);
dm_put_live_table_fast(md);
return r;
}
......@@ -1758,7 +1789,7 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
struct dm_table *map;
if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
map = dm_get_live_table(md);
map = dm_get_live_table_fast(md);
if (map) {
/*
* Request-based dm cares about only own queue for
......@@ -1769,9 +1800,8 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
bdi_bits;
else
r = dm_table_any_congested(map, bdi_bits);
dm_table_put(map);
}
dm_put_live_table_fast(md);
}
return r;
......@@ -1876,12 +1906,14 @@ static struct mapped_device *alloc_dev(int minor)
if (r < 0)
goto bad_minor;
r = init_srcu_struct(&md->io_barrier);
if (r < 0)
goto bad_io_barrier;
md->type = DM_TYPE_NONE;
init_rwsem(&md->io_lock);
mutex_init(&md->suspend_lock);
mutex_init(&md->type_lock);
spin_lock_init(&md->deferred_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
atomic_set(&md->event_nr, 0);
......@@ -1944,6 +1976,8 @@ static struct mapped_device *alloc_dev(int minor)
bad_disk:
blk_cleanup_queue(md->queue);
bad_queue:
cleanup_srcu_struct(&md->io_barrier);
bad_io_barrier:
free_minor(minor);
bad_minor:
module_put(THIS_MODULE);
......@@ -1967,6 +2001,7 @@ static void free_dev(struct mapped_device *md)
bioset_free(md->bs);
blk_integrity_unregister(md->disk);
del_gendisk(md->disk);
cleanup_srcu_struct(&md->io_barrier);
free_minor(minor);
spin_lock(&_minor_lock);
......@@ -2109,7 +2144,6 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
struct dm_table *old_map;
struct request_queue *q = md->queue;
sector_t size;
unsigned long flags;
int merge_is_optional;
size = dm_table_get_size(t);
......@@ -2138,9 +2172,8 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
merge_is_optional = dm_table_merge_is_optional(t);
write_lock_irqsave(&md->map_lock, flags);
old_map = md->map;
md->map = t;
rcu_assign_pointer(md->map, t);
md->immutable_target_type = dm_table_get_immutable_target_type(t);
dm_table_set_restrictions(t, q, limits);
......@@ -2148,7 +2181,7 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
else
clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
write_unlock_irqrestore(&md->map_lock, flags);
dm_sync_table(md);
return old_map;
}
......@@ -2159,15 +2192,13 @@ static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
static struct dm_table *__unbind(struct mapped_device *md)
{
struct dm_table *map = md->map;
unsigned long flags;
if (!map)
return NULL;
dm_table_event_callback(map, NULL, NULL);
write_lock_irqsave(&md->map_lock, flags);
md->map = NULL;
write_unlock_irqrestore(&md->map_lock, flags);
rcu_assign_pointer(md->map, NULL);
dm_sync_table(md);
return map;
}
......@@ -2319,11 +2350,12 @@ 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);
map = dm_get_live_table(md);
map = dm_get_live_table(md, &srcu_idx);
idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
set_bit(DMF_FREEING, &md->flags);
spin_unlock(&_minor_lock);
......@@ -2333,6 +2365,9 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
dm_table_postsuspend_targets(map);
}
/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
dm_put_live_table(md, srcu_idx);
/*
* Rare, but there may be I/O requests still going to complete,
* for example. Wait for all references to disappear.
......@@ -2347,7 +2382,6 @@ static void __dm_destroy(struct mapped_device *md, bool wait)
dm_device_name(md), atomic_read(&md->holders));
dm_sysfs_exit(md);
dm_table_put(map);
dm_table_destroy(__unbind(md));
free_dev(md);
}
......@@ -2404,8 +2438,10 @@ static void dm_wq_work(struct work_struct *work)
struct mapped_device *md = container_of(work, struct mapped_device,
work);
struct bio *c;
int srcu_idx;
struct dm_table *map;
down_read(&md->io_lock);
map = dm_get_live_table(md, &srcu_idx);
while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
spin_lock_irq(&md->deferred_lock);
......@@ -2415,17 +2451,13 @@ static void dm_wq_work(struct work_struct *work)
if (!c)
break;
up_read(&md->io_lock);
if (dm_request_based(md))
generic_make_request(c);
else
__split_and_process_bio(md, c);
down_read(&md->io_lock);
__split_and_process_bio(md, map, c);
}
up_read(&md->io_lock);
dm_put_live_table(md, srcu_idx);
}
static void dm_queue_flush(struct mapped_device *md)
......@@ -2457,10 +2489,10 @@ struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
* reappear.
*/
if (dm_table_has_no_data_devices(table)) {
live_map = dm_get_live_table(md);
live_map = dm_get_live_table_fast(md);
if (live_map)
limits = md->queue->limits;
dm_table_put(live_map);
dm_put_live_table_fast(md);
}
if (!live_map) {
......@@ -2540,7 +2572,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
goto out_unlock;
}
map = dm_get_live_table(md);
map = md->map;
/*
* DMF_NOFLUSH_SUSPENDING must be set before presuspend.
......@@ -2561,7 +2593,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
if (!noflush && do_lockfs) {
r = lock_fs(md);
if (r)
goto out;
goto out_unlock;
}
/*
......@@ -2576,9 +2608,8 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
* (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
* flush_workqueue(md->wq).
*/
down_write(&md->io_lock);
set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
up_write(&md->io_lock);
synchronize_srcu(&md->io_barrier);
/*
* Stop md->queue before flushing md->wq in case request-based
......@@ -2596,10 +2627,9 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
*/
r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
down_write(&md->io_lock);
if (noflush)
clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
up_write(&md->io_lock);
synchronize_srcu(&md->io_barrier);
/* were we interrupted ? */
if (r < 0) {
......@@ -2609,7 +2639,7 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
start_queue(md->queue);
unlock_fs(md);
goto out; /* pushback list is already flushed, so skip flush */
goto out_unlock; /* pushback list is already flushed, so skip flush */
}
/*
......@@ -2622,9 +2652,6 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
dm_table_postsuspend_targets(map);
out:
dm_table_put(map);
out_unlock:
mutex_unlock(&md->suspend_lock);
return r;
......@@ -2639,7 +2666,7 @@ int dm_resume(struct mapped_device *md)
if (!dm_suspended_md(md))
goto out;
map = dm_get_live_table(md);
map = md->map;
if (!map || !dm_table_get_size(map))
goto out;
......@@ -2663,7 +2690,6 @@ int dm_resume(struct mapped_device *md)
r = 0;
out:
dm_table_put(map);
mutex_unlock(&md->suspend_lock);
return r;
......
......@@ -446,9 +446,9 @@ int __must_check dm_set_target_max_io_len(struct dm_target *ti, sector_t len);
/*
* Table reference counting.
*/
struct dm_table *dm_get_live_table(struct mapped_device *md);
void dm_table_get(struct dm_table *t);
void dm_table_put(struct dm_table *t);
struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx);
void dm_put_live_table(struct mapped_device *md, int srcu_idx);
void dm_sync_table(struct mapped_device *md);
/*
* Queries
......
......@@ -267,9 +267,9 @@ enum {
#define DM_DEV_SET_GEOMETRY _IOWR(DM_IOCTL, DM_DEV_SET_GEOMETRY_CMD, struct dm_ioctl)
#define DM_VERSION_MAJOR 4
#define DM_VERSION_MINOR 24
#define DM_VERSION_MINOR 25
#define DM_VERSION_PATCHLEVEL 0
#define DM_VERSION_EXTRA "-ioctl (2013-01-15)"
#define DM_VERSION_EXTRA "-ioctl (2013-06-26)"
/* Status bits */
#define DM_READONLY_FLAG (1 << 0) /* In/Out */
......
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