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Subject[PATCH] Remove might_sleep from wait_event_cmd
Hi

Please apply this before 3.19 is released.

Mikulas


The patch e22b886a8a43b147e1994a9f970f678fc0df2033 introduced a bug in the
raid5 subsystem.

The function raid5_quiesce (and resize_stripes) calls
lock_all_device_hash_locks_irq that disables interrupts and takes a few
spinlocks, then it calls wait_event_cmd with cmd1
unlock_all_device_hash_locks_irq(conf) and cmd2
lock_all_device_hash_locks_irq(conf). cmd1 unlocks the spinlocks and
enables interrupts, cmd2 disables interrupts and locks the spinlock.

The patch e22b886a8a43b147e1994a9f970f678fc0df2033 adds might_sleep() to a
position where spinlocks are taken, thus it introduces a bug.

This patch removes might_sleep() from wait_event_cmd.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

---
include/linux/wait.h | 1 -
1 file changed, 1 deletion(-)

Index: linux-2.6/include/linux/wait.h
===================================================================
--- linux-2.6.orig/include/linux/wait.h 2014-12-30 01:19:25.564231262 +0100
+++ linux-2.6/include/linux/wait.h 2015-02-02 15:30:16.766354658 +0100
@@ -363,7 +363,6 @@ do { \
*/
#define wait_event_cmd(wq, condition, cmd1, cmd2) \
do { \
- might_sleep(); \
if (condition) \
break; \
__wait_event_cmd(wq, condition, cmd1, cmd2); \

\
 
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