Commit 26b924b9 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Mike Snitzer
Browse files

dm cache: replace spin_lock_irqsave with spin_lock_irq 



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 they don't need to
push and pop the flags register.

Signed-off-by: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 235bc861

drivers/md/dm-cache-target.c

+28 −49
Original line number Diff line number Diff line
@@ -74,22 +74,19 @@ static bool __iot_idle_for(struct io_tracker *iot, unsigned long jifs) 
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 *_ws) 
{

	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 *_ws) 
	 * 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 *b) 


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 batcher *b, struct continuation *k) 
 */

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 batcher *b, struct bio *bio) 
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_data(struct bio *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);

}
@@ -756,33 +745,27 @@ static dm_dblock_t oblock_to_dblock(struct cache *cache, dm_oblock_t oblock) 


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;

}
@@ -790,12 +773,10 @@ static bool is_discarded(struct cache *cache, dm_dblock_t b) 
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;

}
@@ -827,17 +808,16 @@ static void remap_to_cache(struct cache *cache, struct bio *bio, 


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,
@@ -1889,17 +1869,16 @@ static void process_deferred_bios(struct work_struct *ws) 
{

	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)

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