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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>
This commit is contained in:
Mikulas Patocka 2009-04-02 19:55:39 +01:00 committed by Alasdair G Kergon
parent 401600dfd3
commit 022c261100
1 changed files with 16 additions and 21 deletions
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37
drivers/md/dm.c
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@ -102,7 +102,6 @@ union map_info *dm_get_mapinfo(struct bio *bio)
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 @@ struct mapped_device {
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 @@ static int queue_io(struct mapped_device *md, struct bio *bio)
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 @@ static void dec_pending(struct dm_io *io, int error)
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 @@ static struct mapped_device *alloc_dev(int minor)
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 @@ static void dm_wq_work(struct work_struct *work)
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 @@ int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
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 ? */