Since neither the RCU-protected code in blk_queue_enter() nor blk_queue_usage_counter_release() sleeps, regular RCU protection is sufficient. Note: scsi_device_quiesce() does not have to be modified since it already uses synchronize_rcu().

Reported-by: Tejun Heo tj@kernel.org Fixes: 3a0a529971ec ("block, scsi: Make SCSI quiesce and resume work reliably") Signed-off-by: Bart Van Assche bart.vanassche@wdc.com Cc: Hannes Reinecke hare@suse.com Cc: Ming Lei ming.lei@redhat.com Cc: Christoph Hellwig hch@lst.de Cc: Johannes Thumshirn jthumshirn@suse.de Cc: Tejun Heo tj@kernel.org Cc: Oleksandr Natalenko oleksandr@natalenko.name Cc: Martin Steigerwald martin@lichtvoll.de Cc: stable@vger.kernel.org # v4.15 --- block/blk-core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c index 5e88c579e896..a0f675f84f86 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -917,7 +917,7 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) bool success = false; int ret;

- rcu_read_lock_sched(); + rcu_read_lock(); if (percpu_ref_tryget_live(&q->q_usage_counter)) { /* * The code that sets the PREEMPT_ONLY flag is @@ -930,7 +930,7 @@ int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) percpu_ref_put(&q->q_usage_counter); } } - rcu_read_unlock_sched(); + rcu_read_unlock();

if (success) return 0;