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-rw-r--r--block/blk-sysfs.c47
1 files changed, 32 insertions, 15 deletions
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index a16a02c..75b5281c 100644
--- 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))