From: Bart Van Assche <bart.vanassche@wdc.com>
Date: Thu, 9 Aug 2018 07:53:37 -0700
Subject: [PATCH] block: Introduce blk_exit_queue()
Git-commit: 4cf6324b17e96b7b7ab4021c6929500934d46750
Patch-Mainline: v4.19-rc1
References: bsc#1131673
This patch does not change any functionality.
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Alexandru Moise <00moses.alexander00@gmail.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
block/blk-core.c | 54 ++++++++++++++++++++++++++++++------------------------
block/blk.h | 1 +
2 files changed, 31 insertions(+), 24 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 3850faf93998..467ae6088825 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -625,6 +625,35 @@ void blk_set_queue_dying(struct request_queue *q)
}
EXPORT_SYMBOL_GPL(blk_set_queue_dying);
+/* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */
+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_cleanup_queue - shutdown a request queue
* @q: request queue to shutdown
@@ -693,30 +722,7 @@ void blk_cleanup_queue(struct request_queue *q)
*/
WARN_ON_ONCE(q->kobj.state_in_sysfs);
- /*
- * 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_exit_queue(q);
if (q->mq_ops)
blk_mq_free_queue(q);
diff --git a/block/blk.h b/block/blk.h
index 9f0878779f94..ae66c27c583b 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -60,6 +60,7 @@ void blk_free_flush_queue(struct blk_flush_queue *q);
int blk_init_rl(struct request_list *rl, struct request_queue *q,
gfp_t gfp_mask);
void blk_exit_rl(struct request_queue *q, struct request_list *rl);
+void blk_exit_queue(struct request_queue *q);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);
void blk_queue_bypass_start(struct request_queue *q);
--
2.16.4