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

[Christoph Hellwig <hch@xxxxxx>]

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@xxxxxx>
---
 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