dm: merge pushback and deferred bio lists
Merge pushback and deferred lists into one list - use deferred list
for both deferred and pushed-back bios.
This will be needed for proper support of barrier bios: it is impossible to
support ordering correctly with two lists because the requests on both lists
will be mixed up.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index ae21833..f570372 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -102,7 +102,6 @@
struct mapped_device {
struct rw_semaphore io_lock;
struct mutex suspend_lock;
- spinlock_t pushback_lock;
rwlock_t map_lock;
atomic_t holders;
atomic_t open_count;
@@ -122,7 +121,7 @@
wait_queue_head_t wait;
struct work_struct work;
struct bio_list deferred;
- struct bio_list pushback;
+ spinlock_t deferred_lock;
/*
* Processing queue (flush/barriers)
@@ -445,7 +444,9 @@
return 1;
}
+ spin_lock_irq(&md->deferred_lock);
bio_list_add(&md->deferred, bio);
+ spin_unlock_irq(&md->deferred_lock);
up_write(&md->io_lock);
return 0; /* deferred successfully */
@@ -529,16 +530,14 @@
if (io->error == DM_ENDIO_REQUEUE) {
/*
* Target requested pushing back the I/O.
- * This must be handled before the sleeper on
- * suspend queue merges the pushback list.
*/
- spin_lock_irqsave(&md->pushback_lock, flags);
+ spin_lock_irqsave(&md->deferred_lock, flags);
if (__noflush_suspending(md))
- bio_list_add(&md->pushback, io->bio);
+ bio_list_add(&md->deferred, io->bio);
else
/* noflush suspend was interrupted. */
io->error = -EIO;
- spin_unlock_irqrestore(&md->pushback_lock, flags);
+ spin_unlock_irqrestore(&md->deferred_lock, flags);
}
end_io_acct(io);
@@ -1096,7 +1095,7 @@
init_rwsem(&md->io_lock);
mutex_init(&md->suspend_lock);
- spin_lock_init(&md->pushback_lock);
+ spin_lock_init(&md->deferred_lock);
rwlock_init(&md->map_lock);
atomic_set(&md->holders, 1);
atomic_set(&md->open_count, 0);
@@ -1410,25 +1409,21 @@
down_write(&md->io_lock);
- while ((c = bio_list_pop(&md->deferred)))
+next_bio:
+ spin_lock_irq(&md->deferred_lock);
+ c = bio_list_pop(&md->deferred);
+ spin_unlock_irq(&md->deferred_lock);
+
+ if (c) {
__split_and_process_bio(md, c);
+ goto next_bio;
+ }
clear_bit(DMF_BLOCK_IO, &md->flags);
up_write(&md->io_lock);
}
-static void __merge_pushback_list(struct mapped_device *md)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&md->pushback_lock, flags);
- clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
- bio_list_merge_head(&md->deferred, &md->pushback);
- bio_list_init(&md->pushback);
- spin_unlock_irqrestore(&md->pushback_lock, flags);
-}
-
static void dm_queue_flush(struct mapped_device *md)
{
queue_work(md->wq, &md->work);
@@ -1572,7 +1567,7 @@
remove_wait_queue(&md->wait, &wait);
if (noflush)
- __merge_pushback_list(md);
+ clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
up_write(&md->io_lock);
/* were we interrupted ? */