Prepare for checking whether or not a request queue is frozen from the hot
path with a minimal performance overhead.
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
block/blk-core.c | 1 +
block/blk-mq.c | 1 +
include/linux/blkdev.h | 2 ++
3 files changed, 4 insertions(+)
diff --git a/block/blk-core.c b/block/blk-core.c
index fdac48aec5ef..001a4ac997ae 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -376,6 +376,7 @@ static void blk_queue_usage_counter_release(struct percpu_ref *ref)
struct request_queue *q =
container_of(ref, struct request_queue, q_usage_counter);
+ blk_queue_flag_set(QUEUE_FLAG_FROZEN, q);
wake_up_all(&q->mq_freeze_wq);
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 0c61492724d2..7919607c1aeb 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -218,6 +218,7 @@ bool __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
WARN_ON_ONCE(q->mq_freeze_depth < 0);
if (!q->mq_freeze_depth) {
percpu_ref_resurrect(&q->q_usage_counter);
+ blk_queue_flag_clear(QUEUE_FLAG_FROZEN, q);
wake_up_all(&q->mq_freeze_wq);
}
unfreeze = blk_unfreeze_check_owner(q);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index a51f92b6c340..77b9067d621a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -641,6 +641,7 @@ enum {
QUEUE_FLAG_INIT_DONE, /* queue is initialized */
QUEUE_FLAG_STATS, /* track IO start and completion times */
QUEUE_FLAG_REGISTERED, /* queue has been registered to a disk */
+ QUEUE_FLAG_FROZEN, /* queue has been frozen */
QUEUE_FLAG_QUIESCED, /* queue has been quiesced */
QUEUE_FLAG_RQ_ALLOC_TIME, /* record rq->alloc_time_ns */
QUEUE_FLAG_HCTX_ACTIVE, /* at least one blk-mq hctx is active */
@@ -676,6 +677,7 @@ void blk_queue_flag_clear(unsigned int flag, struct request_queue *q);
#define blk_noretry_request(rq) \
((rq)->cmd_flags & (REQ_FAILFAST_DEV|REQ_FAILFAST_TRANSPORT| \
REQ_FAILFAST_DRIVER))
+#define blk_queue_frozen(q) test_bit(QUEUE_FLAG_FROZEN, &(q)->queue_flags)
#define blk_queue_quiesced(q) test_bit(QUEUE_FLAG_QUIESCED, &(q)->queue_flags)
#define blk_queue_pm_only(q) atomic_read(&(q)->pm_only)
#define blk_queue_registered(q) test_bit(QUEUE_FLAG_REGISTERED, &(q)->queue_flags)
