diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2009-04-09 03:27:15 +0400 |
|---|---|---|
| committer | Alasdair G Kergon <agk@redhat.com> | 2009-04-09 03:27:15 +0400 |
| commit | 92c639021ca6e962645114f02e356e7feb131d0b (patch) | |
| tree | eee01e9394b09fb3929fd4f3682815e91b87c764 /drivers/md | |
| parent | 3b00b2036fac7a7667d0676a0f80eee575b8c32b (diff) | |
| download | linux-92c639021ca6e962645114f02e356e7feb131d0b.tar.xz | |
dm: remove dm_request loop
Remove queue_io return value and a loop in dm_request.
IO may be submitted to a worker thread with queue_io(). queue_io() sets
DMF_QUEUE_IO_TO_THREAD so that all further IO is queued for the thread. When
the thread finishes its work, it clears DMF_QUEUE_IO_TO_THREAD and from this
point on, requests are submitted from dm_request again. This will be used
for processing barriers.
Remove the loop in dm_request. queue_io() can submit I/Os to the worker thread
even if DMF_QUEUE_IO_TO_THREAD was not set.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/dm.c | 22 |
1 files changed, 7 insertions, 15 deletions
diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 9746c1eb9ef7..db022e5f3912 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -436,21 +436,18 @@ static void end_io_acct(struct dm_io *io) /* * Add the bio to the list of deferred io. */ -static int queue_io(struct mapped_device *md, struct bio *bio) +static void queue_io(struct mapped_device *md, struct bio *bio) { down_write(&md->io_lock); - if (!test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) { - up_write(&md->io_lock); - return 1; - } - spin_lock_irq(&md->deferred_lock); bio_list_add(&md->deferred, bio); spin_unlock_irq(&md->deferred_lock); + if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) + queue_work(md->wq, &md->work); + up_write(&md->io_lock); - return 0; /* deferred successfully */ } /* @@ -953,7 +950,7 @@ static int dm_request(struct request_queue *q, struct bio *bio) * If we're suspended or the thread is processing barriers * we have to queue this io for later. */ - while (test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) { + if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))) { up_read(&md->io_lock); if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) && @@ -962,14 +959,9 @@ static int dm_request(struct request_queue *q, struct bio *bio) return 0; } - if (!queue_io(md, bio)) - return 0; + queue_io(md, bio); - /* - * We're in a while loop, because someone could suspend - * before we get to the following read lock. - */ - down_read(&md->io_lock); + return 0; } __split_and_process_bio(md, bio); |