[PATCH] Use list_splice for blk_abort_queue

Hannes Reinecke
2009-02-27T11:37:08Z

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