From 6a7f897752a24afb391b3766cc33be3e28a1074b Mon Sep 17 00:00:00 2001
From: Joe Thornber <ejt@redhat.com>
Date: Fri, 21 Dec 2012 20:23:31 +0000
Subject: [PATCH] --- yaml --- r: 347945 b: refs/heads/master c:
 563af186df08002d2600c4e718ad8f3bde109f53 h: refs/heads/master i:   347943:
 5d41052ed92f64a51d7426740b4936ee2633a17a v: v3

---
 [refs]                     |  2 +-
 trunk/drivers/md/dm-thin.c | 11 +++++++----
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/[refs] b/[refs]
index 31ccc89e1a59..30c404a5b50c 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: e8088073c9610af017fd47fddd104a2c3afb32e8
+refs/heads/master: 563af186df08002d2600c4e718ad8f3bde109f53
diff --git a/trunk/drivers/md/dm-thin.c b/trunk/drivers/md/dm-thin.c
index 41c9e81ba74a..aeb9e20f5978 100644
--- a/trunk/drivers/md/dm-thin.c
+++ b/trunk/drivers/md/dm-thin.c
@@ -2676,10 +2676,13 @@ static int thin_endio(struct dm_target *ti,
 	if (h->all_io_entry) {
 		INIT_LIST_HEAD(&work);
 		dm_deferred_entry_dec(h->all_io_entry, &work);
-		spin_lock_irqsave(&pool->lock, flags);
-		list_for_each_entry_safe(m, tmp, &work, list)
-			list_add(&m->list, &pool->prepared_discards);
-		spin_unlock_irqrestore(&pool->lock, flags);
+		if (!list_empty(&work)) {
+			spin_lock_irqsave(&pool->lock, flags);
+			list_for_each_entry_safe(m, tmp, &work, list)
+				list_add(&m->list, &pool->prepared_discards);
+			spin_unlock_irqrestore(&pool->lock, flags);
+			wake_worker(pool);
+		}
 	}
 
 	mempool_free(h, pool->endio_hook_pool);