From: Mike Snitzer snitzer@redhat.com
commit 9958f1d9a04efb3db19134482b3f4c6897e0e7b8 upstream.
Now that the writethrough code is much simpler there is no need to track so much state or cascade bio submission (as was done, via writethrough_endio(), to issue origin then cache IO in series).
As such the obsolete writethrough list and workqueue is also removed.
Signed-off-by: Mike Snitzer snitzer@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/md/dm-cache-target.c | 82 ------------------------------------------- 1 file changed, 1 insertion(+), 81 deletions(-)
--- a/drivers/md/dm-cache-target.c +++ b/drivers/md/dm-cache-target.c @@ -410,7 +410,6 @@ struct cache { spinlock_t lock; struct list_head deferred_cells; struct bio_list deferred_bios; - struct bio_list deferred_writethrough_bios; sector_t migration_threshold; wait_queue_head_t migration_wait; atomic_t nr_allocated_migrations; @@ -446,7 +445,6 @@ struct cache { struct dm_kcopyd_client *copier; struct workqueue_struct *wq; struct work_struct deferred_bio_worker; - struct work_struct deferred_writethrough_worker; struct work_struct migration_worker; struct delayed_work waker; struct dm_bio_prison_v2 *prison; @@ -491,15 +489,6 @@ struct per_bio_data { struct dm_bio_prison_cell_v2 *cell; struct dm_hook_info hook_info; sector_t len; - - /* - * writethrough fields. These MUST remain at the end of this - * structure and the 'cache' member must be the first as it - * is used to determine the offset of the writethrough fields. - */ - struct cache *cache; - dm_cblock_t cblock; - struct dm_bio_details bio_details; };
struct dm_cache_migration { @@ -538,11 +527,6 @@ static void wake_deferred_bio_worker(str queue_work(cache->wq, &cache->deferred_bio_worker); }
-static void wake_deferred_writethrough_worker(struct cache *cache) -{ - queue_work(cache->wq, &cache->deferred_writethrough_worker); -} - static void wake_migration_worker(struct cache *cache) { if (passthrough_mode(cache)) @@ -619,15 +603,9 @@ static unsigned lock_level(struct bio *b * Per bio data *--------------------------------------------------------------*/
-/* - * If using writeback, leave out struct per_bio_data's writethrough fields. - */ -#define PB_DATA_SIZE_WB (offsetof(struct per_bio_data, cache)) -#define PB_DATA_SIZE_WT (sizeof(struct per_bio_data)) - static size_t get_per_bio_data_size(struct cache *cache) { - return writethrough_mode(cache) ? PB_DATA_SIZE_WT : PB_DATA_SIZE_WB; + return sizeof(struct per_bio_data); }
static struct per_bio_data *get_per_bio_data(struct bio *bio, size_t data_size) @@ -945,39 +923,6 @@ static void issue_op(struct bio *bio, vo accounted_request(cache, bio); }
-static void defer_writethrough_bio(struct cache *cache, struct bio *bio) -{ - unsigned long flags; - - spin_lock_irqsave(&cache->lock, flags); - bio_list_add(&cache->deferred_writethrough_bios, bio); - spin_unlock_irqrestore(&cache->lock, flags); - - wake_deferred_writethrough_worker(cache); -} - -static void writethrough_endio(struct bio *bio) -{ - struct per_bio_data *pb = get_per_bio_data(bio, PB_DATA_SIZE_WT); - - dm_unhook_bio(&pb->hook_info, bio); - - if (bio->bi_status) { - bio_endio(bio); - return; - } - - dm_bio_restore(&pb->bio_details, bio); - remap_to_cache(pb->cache, bio, pb->cblock); - - /* - * We can't issue this bio directly, since we're in interrupt - * context. So it gets put on a bio list for processing by the - * worker thread. - */ - defer_writethrough_bio(pb->cache, bio); -} - /* * When running in writethrough mode we need to send writes to clean blocks * to both the cache and origin devices. Clone the bio and send them in parallel. @@ -2013,28 +1958,6 @@ static void process_deferred_bios(struct schedule_commit(&cache->committer); }
-static void process_deferred_writethrough_bios(struct work_struct *ws) -{ - struct cache *cache = container_of(ws, struct cache, deferred_writethrough_worker); - - unsigned long flags; - struct bio_list bios; - struct bio *bio; - - bio_list_init(&bios); - - spin_lock_irqsave(&cache->lock, flags); - bio_list_merge(&bios, &cache->deferred_writethrough_bios); - bio_list_init(&cache->deferred_writethrough_bios); - spin_unlock_irqrestore(&cache->lock, flags); - - /* - * These bios have already been through accounted_begin() - */ - while ((bio = bio_list_pop(&bios))) - generic_make_request(bio); -} - /*---------------------------------------------------------------- * Main worker loop *--------------------------------------------------------------*/ @@ -2690,7 +2613,6 @@ static int cache_create(struct cache_arg spin_lock_init(&cache->lock); INIT_LIST_HEAD(&cache->deferred_cells); bio_list_init(&cache->deferred_bios); - bio_list_init(&cache->deferred_writethrough_bios); atomic_set(&cache->nr_allocated_migrations, 0); atomic_set(&cache->nr_io_migrations, 0); init_waitqueue_head(&cache->migration_wait); @@ -2729,8 +2651,6 @@ static int cache_create(struct cache_arg goto bad; } INIT_WORK(&cache->deferred_bio_worker, process_deferred_bios); - INIT_WORK(&cache->deferred_writethrough_worker, - process_deferred_writethrough_bios); INIT_WORK(&cache->migration_worker, check_migrations); INIT_DELAYED_WORK(&cache->waker, do_waker);