[PATCH 2/5] blk-mq: bitmap tag: remove barrier in bt_clear_tag()

From: Ming Lei
Date: Sat May 10 2014 - 13:02:29 EST


The barrier isn't necessary because both atomic_dec_and_test()
and wake_up() implicate one barrier.

Signed-off-by: Ming Lei <tom.leiming@xxxxxxxxx>
---
block/blk-mq-tag.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index b8b968d..777aad7 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -243,7 +243,6 @@ static void bt_clear_tag(struct blk_mq_bitmap_tags *bt, unsigned int tag)

bs = bt_wake_ptr(bt);
if (bs && atomic_dec_and_test(&bs->wait_cnt)) {
- smp_mb__after_clear_bit();
atomic_set(&bs->wait_cnt, BT_WAIT_BATCH);
bt_index_inc(&bt->wake_index);
wake_up(&bs->wait);
--
1.7.9.5

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