[PATCH] fix NMI lockup with CFQ scheduler

The current problem seen is that the queue lock is actually in the
SCSI device structure, so when that structure is freed on device
release, we go boom if the queue tries to access the lock again.

The fix here is to move the lock from the scsi_device to the queue.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 70ac2860a605..ef1afc178c0a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -355,8 +355,11 @@ struct request_queue
         unsigned long           queue_flags;
 
         /*
-         * protects queue structures from reentrancy
+         * protects queue structures from reentrancy. ->__queue_lock should
+         * _never_ be used directly, it is queue private. always use
+         * ->queue_lock.
          */
+        spinlock_t              __queue_lock;
         spinlock_t              *queue_lock;
 
         /*