[PATCH] Use list_splice for blk_abort_queue

[hare@suse.de (Hannes Reinecke)]

blk_abort_queue takes the queue_lock with spinlock_irqsave and walks
the timer_list with list_for_each_entry_safe. Since a path to a SCSI
device just failed, the rport state is FC_PORTSTATE_BLOCKED. This
rport state triggers blk_add_timer(), which in turn calls
list_add_tail() to move the request to the end of timer_list. Thus,
the list_for_each_XXX loop never reaches the end of the timer_list.
By using list_splice_init() we're breaking the loop and process only
the requests present on the timeout_list when blk_abort_queue() is
called.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Tested-by: Christof Schmitt <christof.schmitt@de.ibm.com>
---
 block/blk-timeout.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/block/blk-timeout.c b/block/blk-timeout.c
index a095353..67bcc3f 100644
--- a/block/blk-timeout.c
+++ b/block/blk-timeout.c
@@ -209,12 +209,15 @@ void blk_abort_queue(struct request_queue *q)
 {
 	unsigned long flags;
 	struct request *rq, *tmp;
+	LIST_HEAD(list);
 
 	spin_lock_irqsave(q->queue_lock, flags);
 
 	elv_abort_queue(q);
 
-	list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list)
+	list_splice_init(&q->timeout_list, &list);
+
+	list_for_each_entry_safe(rq, tmp, &list, timeout_list)
 		blk_abort_request(rq);
 
 	spin_unlock_irqrestore(q->queue_lock, flags);
-- 
1.5.3.2