If we are in a place where it is known that interrupts are enabled, functions spin_lock_irq/spin_unlock_irq should be used instead of spin_lock_irqsave/spin_unlock_irqrestore.
spin_lock_irq and spin_unlock_irq are faster because the don't need to push and pop the flags register. Signed-off-by: Mikulas Patocka <[email protected]> --- drivers/md/dm-cache-target.c | 99 ++++++++++++------------------------------- 1 file changed, 28 insertions(+), 71 deletions(-) Index: linux-2.6/drivers/md/dm-cache-target.c =================================================================== --- linux-2.6.orig/drivers/md/dm-cache-target.c 2019-10-16 17:05:31.000000000 +0200 +++ linux-2.6/drivers/md/dm-cache-target.c 2019-10-16 17:09:35.000000000 +0200 @@ -74,22 +74,19 @@ static bool __iot_idle_for(struct io_tra static bool iot_idle_for(struct io_tracker *iot, unsigned long jifs) { bool r; - unsigned long flags; - spin_lock_irqsave(&iot->lock, flags); + spin_lock_irq(&iot->lock); r = __iot_idle_for(iot, jifs); - spin_unlock_irqrestore(&iot->lock, flags); + spin_unlock_irq(&iot->lock); return r; } static void iot_io_begin(struct io_tracker *iot, sector_t len) { - unsigned long flags; - - spin_lock_irqsave(&iot->lock, flags); + spin_lock_irq(&iot->lock); iot->in_flight += len; - spin_unlock_irqrestore(&iot->lock, flags); + spin_unlock_irq(&iot->lock); } static void __iot_io_end(struct io_tracker *iot, sector_t len) @@ -172,7 +169,6 @@ static void __commit(struct work_struct { struct batcher *b = container_of(_ws, struct batcher, commit_work); blk_status_t r; - unsigned long flags; struct list_head work_items; struct work_struct *ws, *tmp; struct continuation *k; @@ -186,12 +182,12 @@ static void __commit(struct work_struct * We have to grab these before the commit_op to avoid a race * condition. */ - spin_lock_irqsave(&b->lock, flags); + spin_lock_irq(&b->lock); list_splice_init(&b->work_items, &work_items); bio_list_merge(&bios, &b->bios); bio_list_init(&b->bios); b->commit_scheduled = false; - spin_unlock_irqrestore(&b->lock, flags); + spin_unlock_irq(&b->lock); r = b->commit_op(b->commit_context); @@ -238,13 +234,12 @@ static void async_commit(struct batcher static void continue_after_commit(struct batcher *b, struct continuation *k) { - unsigned long flags; bool commit_scheduled; - spin_lock_irqsave(&b->lock, flags); + spin_lock_irq(&b->lock); commit_scheduled = b->commit_scheduled; list_add_tail(&k->ws.entry, &b->work_items); - spin_unlock_irqrestore(&b->lock, flags); + spin_unlock_irq(&b->lock); if (commit_scheduled) async_commit(b); @@ -255,13 +250,12 @@ static void continue_after_commit(struct */ static void issue_after_commit(struct batcher *b, struct bio *bio) { - unsigned long flags; bool commit_scheduled; - spin_lock_irqsave(&b->lock, flags); + spin_lock_irq(&b->lock); commit_scheduled = b->commit_scheduled; bio_list_add(&b->bios, bio); - spin_unlock_irqrestore(&b->lock, flags); + spin_unlock_irq(&b->lock); if (commit_scheduled) async_commit(b); @@ -273,12 +267,11 @@ static void issue_after_commit(struct ba static void schedule_commit(struct batcher *b) { bool immediate; - unsigned long flags; - spin_lock_irqsave(&b->lock, flags); + spin_lock_irq(&b->lock); immediate = !list_empty(&b->work_items) || !bio_list_empty(&b->bios); b->commit_scheduled = true; - spin_unlock_irqrestore(&b->lock, flags); + spin_unlock_irq(&b->lock); if (immediate) async_commit(b); @@ -630,23 +623,19 @@ static struct per_bio_data *init_per_bio static void defer_bio(struct cache *cache, struct bio *bio) { - unsigned long flags; - - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); bio_list_add(&cache->deferred_bios, bio); - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); wake_deferred_bio_worker(cache); } static void defer_bios(struct cache *cache, struct bio_list *bios) { - unsigned long flags; - - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); bio_list_merge(&cache->deferred_bios, bios); bio_list_init(bios); - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); wake_deferred_bio_worker(cache); } @@ -662,10 +651,6 @@ static bool bio_detain_shared(struct cac struct dm_bio_prison_cell_v2 *cell_prealloc, *cell; cell_prealloc = alloc_prison_cell(cache); /* FIXME: allow wait if calling from worker */ - if (!cell_prealloc) { - defer_bio(cache, bio); - return false; - } build_key(oblock, end, &key); r = dm_cell_get_v2(cache->prison, &key, lock_level(bio), bio, cell_prealloc, &cell); @@ -760,33 +745,27 @@ static dm_dblock_t oblock_to_dblock(stru static void set_discard(struct cache *cache, dm_dblock_t b) { - unsigned long flags; - BUG_ON(from_dblock(b) >= from_dblock(cache->discard_nr_blocks)); atomic_inc(&cache->stats.discard_count); - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); set_bit(from_dblock(b), cache->discard_bitset); - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); } static void clear_discard(struct cache *cache, dm_dblock_t b) { - unsigned long flags; - - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); clear_bit(from_dblock(b), cache->discard_bitset); - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); } static bool is_discarded(struct cache *cache, dm_dblock_t b) { int r; - unsigned long flags; - - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); r = test_bit(from_dblock(b), cache->discard_bitset); - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); return r; } @@ -794,12 +773,10 @@ static bool is_discarded(struct cache *c static bool is_discarded_oblock(struct cache *cache, dm_oblock_t b) { int r; - unsigned long flags; - - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); r = test_bit(from_dblock(oblock_to_dblock(cache, b)), cache->discard_bitset); - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); return r; } @@ -831,17 +808,16 @@ static void remap_to_cache(struct cache static void check_if_tick_bio_needed(struct cache *cache, struct bio *bio) { - unsigned long flags; struct per_bio_data *pb; - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); if (cache->need_tick_bio && !op_is_flush(bio->bi_opf) && bio_op(bio) != REQ_OP_DISCARD) { pb = get_per_bio_data(bio); pb->tick = true; cache->need_tick_bio = false; } - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); } static void __remap_to_origin_clear_discard(struct cache *cache, struct bio *bio, @@ -1491,11 +1467,6 @@ static int mg_lock_writes(struct dm_cach struct dm_bio_prison_cell_v2 *prealloc; prealloc = alloc_prison_cell(cache); - if (!prealloc) { - DMERR_LIMIT("%s: alloc_prison_cell failed", cache_device_name(cache)); - mg_complete(mg, false); - return -ENOMEM; - } /* * Prevent writes to the block, but allow reads to continue. @@ -1533,11 +1504,6 @@ static int mg_start(struct cache *cache, } mg = alloc_migration(cache); - if (!mg) { - policy_complete_background_work(cache->policy, op, false); - background_work_end(cache); - return -ENOMEM; - } mg->op = op; mg->overwrite_bio = bio; @@ -1626,10 +1592,6 @@ static int invalidate_lock(struct dm_cac struct dm_bio_prison_cell_v2 *prealloc; prealloc = alloc_prison_cell(cache); - if (!prealloc) { - invalidate_complete(mg, false); - return -ENOMEM; - } build_key(mg->invalidate_oblock, oblock_succ(mg->invalidate_oblock), &key); r = dm_cell_lock_v2(cache->prison, &key, @@ -1667,10 +1629,6 @@ static int invalidate_start(struct cache return -EPERM; mg = alloc_migration(cache); - if (!mg) { - background_work_end(cache); - return -ENOMEM; - } mg->overwrite_bio = bio; mg->invalidate_cblock = cblock; @@ -1911,17 +1869,16 @@ static void process_deferred_bios(struct { struct cache *cache = container_of(ws, struct cache, deferred_bio_worker); - unsigned long flags; bool commit_needed = false; struct bio_list bios; struct bio *bio; bio_list_init(&bios); - spin_lock_irqsave(&cache->lock, flags); + spin_lock_irq(&cache->lock); bio_list_merge(&bios, &cache->deferred_bios); bio_list_init(&cache->deferred_bios); - spin_unlock_irqrestore(&cache->lock, flags); + spin_unlock_irq(&cache->lock); while ((bio = bio_list_pop(&bios))) { if (bio->bi_opf & REQ_PREFLUSH) -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
