Updated kernel (2.6.27.41).

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.39 / patches.fixes / blk-timeout-splice-timeout-list

diff --git a/src/patches/suse-2.6.27.39/patches.fixes/blk-timeout-splice-timeout-list b/src/patches/suse-2.6.27.39/patches.fixes/blk-timeout-splice-timeout-list
deleted file mode 100644 (file)
index d9198ac..0000000
--- a/src/patches/suse-2.6.27.39/patches.fixes/blk-timeout-splice-timeout-list
+++ /dev/null
@@ -1,65 +0,0 @@
-From: Hannes Reinecke <hare@suse.de>
-Subject: Deadlock during multipath failover
-References: bnc#475107
-
-During multipath failover tests with SCSI on System z, the kernel
-deadlocks in this situation:
-
->  STACK:
->  0 blk_add_timer+206 [0x2981ea]
->  1 blk_rq_timed_out+132 [0x2982a8]
->  2 blk_abort_request+114 [0x29833e]
->  3 blk_abort_queue+92 [0x2983a8]
->  4 deactivate_path+74 [0x3e00009625a]
->  5 run_workqueue+236 [0x149e04]
->  6 worker_thread+294 [0x149fce]
->  7 kthread+110 [0x14f436]
->  8 kernel_thread_starter+6 [0x10941a]
-
-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()
-that calls list_add_tail() to move the request to the end of
-timer_list. Thus, the list_for_each_entry_safe never reaches
-the end of the timer_list, it continously moves the requests
-to the end of the list.
-
-The rport state FC_PORTSTATE_BLOCKED would end when the function
-fc_timeout_deleted_rport() would run to remove the rport. But
-this function was schedules from queue_delayed_work.
-The timer already expired, but the timer function does not run,
-because the timer interrupt is disabled from the
-spinlock_irqsave call.
-
-But just using a list_splice_init() here we will be traversing
-our private list and break the deadlock.
-And the timer would be triggered correctly as blk_add_timer()
-will always add a one second delay here, during which we should
-be able to process the list.
-
-Signed-off-by: Hannes Reinecke <hare@suse.de>
-
----
- block/blk-timeout.c |    5 ++++-
- 1 file changed, 4 insertions(+), 1 deletion(-)
-
---- a/block/blk-timeout.c
-+++ b/block/blk-timeout.c
-@@ -150,12 +150,15 @@ void blk_abort_queue(struct request_queu
- {
-       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);