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authorMikulas Patocka <mpatocka@redhat.com>2009-04-08 19:27:15 -0400
committerAlasdair G Kergon <agk@redhat.com>2009-04-08 19:27:15 -0400
commit92c639021ca6e962645114f02e356e7feb131d0b (patch)
treeeee01e9394b09fb3929fd4f3682815e91b87c764 /drivers/md
parent3b00b2036fac7a7667d0676a0f80eee575b8c32b (diff)
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.c22
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)
436/* 436/*
437 * Add the bio to the list of deferred io. 437 * Add the bio to the list of deferred io.
438 */ 438 */
439static int queue_io(struct mapped_device *md, struct bio *bio) 439static void queue_io(struct mapped_device *md, struct bio *bio)
440{ 440{
441 down_write(&md->io_lock); 441 down_write(&md->io_lock);
442 442
443 if (!test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) {
444 up_write(&md->io_lock);
445 return 1;
446 }
447
448 spin_lock_irq(&md->deferred_lock); 443 spin_lock_irq(&md->deferred_lock);
449 bio_list_add(&md->deferred, bio); 444 bio_list_add(&md->deferred, bio);
450 spin_unlock_irq(&md->deferred_lock); 445 spin_unlock_irq(&md->deferred_lock);
451 446
447 if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))
448 queue_work(md->wq, &md->work);
449
452 up_write(&md->io_lock); 450 up_write(&md->io_lock);
453 return 0; /* deferred successfully */
454} 451}
455 452
456/* 453/*
@@ -953,7 +950,7 @@ static int dm_request(struct request_queue *q, struct bio *bio)
953 * If we're suspended or the thread is processing barriers 950 * If we're suspended or the thread is processing barriers
954 * we have to queue this io for later. 951 * we have to queue this io for later.
955 */ 952 */
956 while (test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) { 953 if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))) {
957 up_read(&md->io_lock); 954 up_read(&md->io_lock);
958 955
959 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) && 956 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)
962 return 0; 959 return 0;
963 } 960 }
964 961
965 if (!queue_io(md, bio)) 962 queue_io(md, bio);
966 return 0;
967 963
968 /* 964 return 0;
969 * We're in a while loop, because someone could suspend
970 * before we get to the following read lock.
971 */
972 down_read(&md->io_lock);
973 } 965 }
974 966
975 __split_and_process_bio(md, bio); 967 __split_and_process_bio(md, bio);