From: majianpeng <majianpeng@gmail.com>
Date: Tue, 13 Mar 2012 00:21:25 +0000 (+1100)
Subject: md/raid5: use atomic_dec_return() instead of atomic_dec() and atomic_read().
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=41fe75f60bcd4d698daed3e54bb099227358ce58;p=mv-sheeva.git

md/raid5: use atomic_dec_return() instead of atomic_dec() and atomic_read().

Signed-off-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index 3f55145ff22..99b2bbf8b5d 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -208,11 +208,10 @@ static void __release_stripe(struct r5conf *conf, struct stripe_head *sh)
 			md_wakeup_thread(conf->mddev->thread);
 		} else {
 			BUG_ON(stripe_operations_active(sh));
-			if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state)) {
-				atomic_dec(&conf->preread_active_stripes);
-				if (atomic_read(&conf->preread_active_stripes) < IO_THRESHOLD)
+			if (test_and_clear_bit(STRIPE_PREREAD_ACTIVE, &sh->state))
+				if (atomic_dec_return(&conf->preread_active_stripes)
+				    < IO_THRESHOLD)
 					md_wakeup_thread(conf->mddev->thread);
-			}
 			atomic_dec(&conf->active_stripes);
 			if (!test_bit(STRIPE_EXPANDING, &sh->state)) {
 				list_add_tail(&sh->lru, &conf->inactive_list);