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authorMilan Broz <mbroz@redhat.com>2007-10-19 17:38:58 -0400
committerAlasdair G Kergon <agk@redhat.com>2007-10-19 21:01:14 -0400
commitcabf08e4d3d1181d7c408edae97fb4d1c31518af (patch)
treeb931cc050b8294a6f04790683e191e324268bad6 /drivers/md
parent9934a8bea2fc67e6f07d74304eca2a91d251bfe8 (diff)
dm crypt: add post processing queue
Add post-processing queue (per crypt device) for read operations. Current implementation uses only one queue for all operations and this can lead to starvation caused by many requests waiting for memory allocation. But the needed memory-releasing operation is queued after these requests (in the same queue). Signed-off-by: Milan Broz <mbroz@redhat.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/dm-crypt.c67
1 files changed, 51 insertions, 16 deletions
diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 126ed21e6b17..357387fa10ca 100644
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -36,7 +36,6 @@ struct dm_crypt_io {
36 struct work_struct work; 36 struct work_struct work;
37 atomic_t pending; 37 atomic_t pending;
38 int error; 38 int error;
39 int post_process;
40}; 39};
41 40
42/* 41/*
@@ -80,7 +79,8 @@ struct crypt_config {
80 mempool_t *page_pool; 79 mempool_t *page_pool;
81 struct bio_set *bs; 80 struct bio_set *bs;
82 81
83 struct workqueue_struct *queue; 82 struct workqueue_struct *io_queue;
83 struct workqueue_struct *crypt_queue;
84 /* 84 /*
85 * crypto related data 85 * crypto related data
86 */ 86 */
@@ -476,19 +476,36 @@ static void dec_pending(struct dm_crypt_io *io, int error)
476} 476}
477 477
478/* 478/*
479 * kcryptd: 479 * kcryptd/kcryptd_io:
480 * 480 *
481 * Needed because it would be very unwise to do decryption in an 481 * Needed because it would be very unwise to do decryption in an
482 * interrupt context. 482 * interrupt context.
483 *
484 * kcryptd performs the actual encryption or decryption.
485 *
486 * kcryptd_io performs the IO submission.
487 *
488 * They must be separated as otherwise the final stages could be
489 * starved by new requests which can block in the first stages due
490 * to memory allocation.
483 */ 491 */
484static void kcryptd_do_work(struct work_struct *work); 492static void kcryptd_do_work(struct work_struct *work);
493static void kcryptd_do_crypt(struct work_struct *work);
485 494
486static void kcryptd_queue_io(struct dm_crypt_io *io) 495static void kcryptd_queue_io(struct dm_crypt_io *io)
487{ 496{
488 struct crypt_config *cc = io->target->private; 497 struct crypt_config *cc = io->target->private;
489 498
490 INIT_WORK(&io->work, kcryptd_do_work); 499 INIT_WORK(&io->work, kcryptd_do_work);
491 queue_work(cc->queue, &io->work); 500 queue_work(cc->io_queue, &io->work);
501}
502
503static void kcryptd_queue_crypt(struct dm_crypt_io *io)
504{
505 struct crypt_config *cc = io->target->private;
506
507 INIT_WORK(&io->work, kcryptd_do_crypt);
508 queue_work(cc->crypt_queue, &io->work);
492} 509}
493 510
494static void crypt_endio(struct bio *clone, int error) 511static void crypt_endio(struct bio *clone, int error)
@@ -511,8 +528,7 @@ static void crypt_endio(struct bio *clone, int error)
511 } 528 }
512 529
513 bio_put(clone); 530 bio_put(clone);
514 io->post_process = 1; 531 kcryptd_queue_crypt(io);
515 kcryptd_queue_io(io);
516 return; 532 return;
517 533
518out: 534out:
@@ -634,10 +650,16 @@ static void kcryptd_do_work(struct work_struct *work)
634{ 650{
635 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work); 651 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
636 652
637 if (io->post_process) 653 if (bio_data_dir(io->base_bio) == READ)
638 process_read_endio(io);
639 else if (bio_data_dir(io->base_bio) == READ)
640 process_read(io); 654 process_read(io);
655}
656
657static void kcryptd_do_crypt(struct work_struct *work)
658{
659 struct dm_crypt_io *io = container_of(work, struct dm_crypt_io, work);
660
661 if (bio_data_dir(io->base_bio) == READ)
662 process_read_endio(io);
641 else 663 else
642 process_write(io); 664 process_write(io);
643} 665}
@@ -870,16 +892,24 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
870 } else 892 } else
871 cc->iv_mode = NULL; 893 cc->iv_mode = NULL;
872 894
873 cc->queue = create_singlethread_workqueue("kcryptd"); 895 cc->io_queue = create_singlethread_workqueue("kcryptd_io");
874 if (!cc->queue) { 896 if (!cc->io_queue) {
897 ti->error = "Couldn't create kcryptd io queue";
898 goto bad_io_queue;
899 }
900
901 cc->crypt_queue = create_singlethread_workqueue("kcryptd");
902 if (!cc->crypt_queue) {
875 ti->error = "Couldn't create kcryptd queue"; 903 ti->error = "Couldn't create kcryptd queue";
876 goto bad_queue; 904 goto bad_crypt_queue;
877 } 905 }
878 906
879 ti->private = cc; 907 ti->private = cc;
880 return 0; 908 return 0;
881 909
882bad_queue: 910bad_crypt_queue:
911 destroy_workqueue(cc->io_queue);
912bad_io_queue:
883 kfree(cc->iv_mode); 913 kfree(cc->iv_mode);
884bad_iv_mode: 914bad_iv_mode:
885 dm_put_device(ti, cc->dev); 915 dm_put_device(ti, cc->dev);
@@ -905,7 +935,8 @@ static void crypt_dtr(struct dm_target *ti)
905{ 935{
906 struct crypt_config *cc = (struct crypt_config *) ti->private; 936 struct crypt_config *cc = (struct crypt_config *) ti->private;
907 937
908 destroy_workqueue(cc->queue); 938 destroy_workqueue(cc->io_queue);
939 destroy_workqueue(cc->crypt_queue);
909 940
910 bioset_free(cc->bs); 941 bioset_free(cc->bs);
911 mempool_destroy(cc->page_pool); 942 mempool_destroy(cc->page_pool);
@@ -931,9 +962,13 @@ static int crypt_map(struct dm_target *ti, struct bio *bio,
931 io = mempool_alloc(cc->io_pool, GFP_NOIO); 962 io = mempool_alloc(cc->io_pool, GFP_NOIO);
932 io->target = ti; 963 io->target = ti;
933 io->base_bio = bio; 964 io->base_bio = bio;
934 io->error = io->post_process = 0; 965 io->error = 0;
935 atomic_set(&io->pending, 0); 966 atomic_set(&io->pending, 0);
936 kcryptd_queue_io(io); 967
968 if (bio_data_dir(io->base_bio) == READ)
969 kcryptd_queue_io(io);
970 else
971 kcryptd_queue_crypt(io);
937 972
938 return DM_MAPIO_SUBMITTED; 973 return DM_MAPIO_SUBMITTED;
939} 974}