[PATCH] block: Move elevator exit from blk_cleanup_queue() to blk_release_queue()

[Jarkko Lavinen]

If block_cleanup_queue() should not remove elevator if it is still
in use. Better call the elevator exit in blk_release_queue() when
all the reference to queue are gone.  Since drivers could use queue
locks which are freed after returning from blk_cleanup_queue(),
switch the queue lock to internal one.

Signed-off-by: Jarkko Lavinen <jarkko.lavinen@xxxxxxxxx>
---
 block/blk-core.c  |    8 ++++++--
 block/blk-sysfs.c |    3 +++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 9daf621..8d7d5aa 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -449,6 +449,8 @@ void blk_put_queue(struct request_queue *q)
 
 void blk_cleanup_queue(struct request_queue *q)
 {
+	spinlock_t *oldlock;
+
 	/*
 	 * We know we have process context here, so we can be a little
 	 * cautious and ensure that pending block actions on this device
@@ -461,8 +463,10 @@ void blk_cleanup_queue(struct request_queue *q)
 	queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
 	mutex_unlock(&q->sysfs_lock);
 
-	if (q->elevator)
-		elevator_exit(q->elevator);
+	oldlock = q->queue_lock;
+	spin_lock_irq(oldlock);
+	q->queue_lock = &q->__queue_lock;
+	spin_unlock_irq(oldlock);
 
 	blk_put_queue(q);
 }
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 21e275d..8ac3e5b 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -304,6 +304,9 @@ static void blk_release_queue(struct kobject *kobj)
 		container_of(kobj, struct request_queue, kobj);
 	struct request_list *rl = &q->rq;
 
+	if (q->elevator)
+		elevator_exit(q->elevator);
+
 	blk_sync_queue(q);
 
 	if (rl->rq_pool)
-- 
1.6.5


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