This patch does not change any functionality.

Signed-off-by: Bart Van Assche bart.vanassche@wdc.com Cc: Christoph Hellwig hch@lst.de Cc: Ming Lei ming.lei@redhat.com Cc: Omar Sandoval osandov@fb.com Cc: Johannes Thumshirn jthumshirn@suse.de Cc: Alexandru Moise 00moses.alexander00@gmail.com Cc: Joseph Qi joseph.qi@linux.alibaba.com Cc: stable@vger.kernel.org --- 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 7c65e297a4f1..5fbfa8484c95 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -719,6 +719,35 @@ 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 @@ -788,30 +817,7 @@ 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 6adae8f94279..aeb8026f4d7b 100644 --- a/block/blk.h +++ b/block/blk.h @@ -130,6 +130,7 @@ 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);