[dm-devel] [PATCH] dm-snap: optimize track_chunk

[Mikulas Patocka]

dm-snap: optimize track_chunk

track_chunk is always called with interrupts enabled. Consequently, we
do not need to save and restore interrupt state in "flags" variable.
This patch changes spin_lock_irqsave to spin_lock_irq and
spin_unlock_irqrestore to spin_unlock_irq.

Signed-off-by: Mikulas Patocka <mpatocka at redhat.com>

---
 drivers/md/dm-snap.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Index: linux-3.6.2-fast/drivers/md/dm-snap.c
===================================================================
--- linux-3.6.2-fast.orig/drivers/md/dm-snap.c	2012-10-17 00:43:01.000000000 +0200
+++ linux-3.6.2-fast/drivers/md/dm-snap.c	2012-10-17 00:43:22.000000000 +0200
@@ -201,14 +201,13 @@ static struct dm_snap_tracked_chunk *tra
 {
 	struct dm_snap_tracked_chunk *c = mempool_alloc(s->tracked_chunk_pool,
 							GFP_NOIO);
-	unsigned long flags;
 
 	c->chunk = chunk;
 
-	spin_lock_irqsave(&s->tracked_chunk_lock, flags);
+	spin_lock_irq(&s->tracked_chunk_lock);
 	hlist_add_head(&c->node,
 		       &s->tracked_chunk_hash[DM_TRACKED_CHUNK_HASH(chunk)]);
-	spin_unlock_irqrestore(&s->tracked_chunk_lock, flags);
+	spin_unlock_irq(&s->tracked_chunk_lock);
 
 	return c;
 }