[PATCH 25/26] block: move the skip_tagset_quiesce flag to queue_limits

[Christoph Hellwig]

Move the skip_tagset_quiesce flag into the queue_limits feature field so
that it can be set atomically and all I/O is frozen when changing the
flag.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 block/blk-mq-debugfs.c   | 1 -
 drivers/nvme/host/core.c | 8 +++++---
 include/linux/blkdev.h   | 6 ++++--
 3 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 8b5a68861c119b..344f9e503bdb32 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -93,7 +93,6 @@ static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
 	QUEUE_FLAG_NAME(HCTX_ACTIVE),
 	QUEUE_FLAG_NAME(SQ_SCHED),
-	QUEUE_FLAG_NAME(SKIP_TAGSET_QUIESCE),
 };
 #undef QUEUE_FLAG_NAME
 
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 31e752e8d632cd..bf410d10b12006 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4489,13 +4489,15 @@ int nvme_alloc_io_tag_set(struct nvme_ctrl *ctrl, struct blk_mq_tag_set *set,
 		return ret;
 
 	if (ctrl->ops->flags & NVME_F_FABRICS) {
-		ctrl->connect_q = blk_mq_alloc_queue(set, NULL, NULL);
+		struct queue_limits lim = {
+			.features	= BLK_FEAT_SKIP_TAGSET_QUIESCE,
+		};
+
+		ctrl->connect_q = blk_mq_alloc_queue(set, &lim, NULL);
         	if (IS_ERR(ctrl->connect_q)) {
 			ret = PTR_ERR(ctrl->connect_q);
 			goto out_free_tag_set;
 		}
-		blk_queue_flag_set(QUEUE_FLAG_SKIP_TAGSET_QUIESCE,
-				   ctrl->connect_q);
 	}
 
 	ctrl->tagset = set;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index cc4f6e64e8e3f5..d7ad25def6e50b 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -322,6 +322,9 @@ enum {
 
 	/* supports PCI(e) p2p requests */
 	BLK_FEAT_PCI_P2PDMA			= (1u << 12),
+
+	/* skip this queue in blk_mq_(un)quiesce_tagset */
+	BLK_FEAT_SKIP_TAGSET_QUIESCE		= (1u << 13),
 };
 
 /*
@@ -594,7 +597,6 @@ struct request_queue {
 #define QUEUE_FLAG_RQ_ALLOC_TIME 27	/* record rq->alloc_time_ns */
 #define QUEUE_FLAG_HCTX_ACTIVE	28	/* at least one blk-mq hctx is active */
 #define QUEUE_FLAG_SQ_SCHED     30	/* single queue style io dispatch */
-#define QUEUE_FLAG_SKIP_TAGSET_QUIESCE	31 /* quiesce_tagset skip the queue*/
 
 #define QUEUE_FLAG_MQ_DEFAULT	(1UL << QUEUE_FLAG_SAME_COMP)
 
@@ -629,7 +631,7 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
 #define blk_queue_registered(q)	test_bit(QUEUE_FLAG_REGISTERED, &(q)->queue_flags)
 #define blk_queue_sq_sched(q)	test_bit(QUEUE_FLAG_SQ_SCHED, &(q)->queue_flags)
 #define blk_queue_skip_tagset_quiesce(q) \
-	test_bit(QUEUE_FLAG_SKIP_TAGSET_QUIESCE, &(q)->queue_flags)
+	((q)->limits.features & BLK_FEAT_SKIP_TAGSET_QUIESCE)
 
 extern void blk_set_pm_only(struct request_queue *q);
 extern void blk_clear_pm_only(struct request_queue *q);
-- 
2.43.0