Merge branch 'for-5.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj...

[thirdparty/linux.git] / block / blk-sysfs.c

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index a16a02c52a8538311974343137abd82b00f72443..977c659dcd1846f193ee525b36cd1c6ccecb2684 100644 (file)
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -840,6 +840,36 @@ static void blk_free_queue_rcu(struct rcu_head *rcu_head)
        kmem_cache_free(blk_requestq_cachep, q);
 }
 
+/* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
+static void blk_exit_queue(struct request_queue *q)
+{
+       /*
+        * Since the I/O scheduler exit code may access cgroup information,
+        * perform I/O scheduler exit before disassociating from the block
+        * cgroup controller.
+        */
+       if (q->elevator) {
+               ioc_clear_queue(q);
+               __elevator_exit(q, q->elevator);
+               q->elevator = NULL;
+       }
+
+       /*
+        * Remove all references to @q from the block cgroup controller before
+        * restoring @q->queue_lock to avoid that restoring this pointer causes
+        * e.g. blkcg_print_blkgs() to crash.
+        */
+       blkcg_exit_queue(q);
+
+       /*
+        * Since the cgroup code may dereference the @q->backing_dev_info
+        * pointer, only decrease its reference count after having removed the
+        * association with the block cgroup controller.
+        */
+       bdi_put(q->backing_dev_info);
+}
+
+
 /**
  * __blk_release_queue - release a request queue
  * @work: pointer to the release_work member of the request queue to be released
@@ -860,23 +890,10 @@ static void __blk_release_queue(struct work_struct *work)
                blk_stat_remove_callback(q, q->poll_cb);
        blk_stat_free_callback(q->poll_cb);
 
-       if (!blk_queue_dead(q)) {
-               /*
-                * Last reference was dropped without having called
-                * blk_cleanup_queue().
-                */
-               WARN_ONCE(blk_queue_init_done(q),
-                         "request queue %p has been registered but blk_cleanup_queue() has not been called for that queue\n",
-                         q);
-               blk_exit_queue(q);
-       }
-
-       WARN(blk_queue_root_blkg(q),
-            "request queue %p is being released but it has not yet been removed from the blkcg controller\n",
-            q);
-
        blk_free_queue_stats(q->stats);
 
+       blk_exit_queue(q);
+
        blk_queue_free_zone_bitmaps(q);
 
        if (queue_is_mq(q))