[PATCH 24/26] block: move the pci_p2pdma flag to queue_limits

[Christoph Hellwig]

Move the pci_p2pdma 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   | 7 ++++---
 3 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index f2fd72f4414ae8..8b5a68861c119b 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -90,7 +90,6 @@ static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(STATS),
 	QUEUE_FLAG_NAME(REGISTERED),
 	QUEUE_FLAG_NAME(QUIESCED),
-	QUEUE_FLAG_NAME(PCI_P2PDMA),
 	QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
 	QUEUE_FLAG_NAME(HCTX_ACTIVE),
 	QUEUE_FLAG_NAME(SQ_SCHED),
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 5ecf762d7c8837..31e752e8d632cd 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -3735,6 +3735,9 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info)
 
 	if (ctrl->opts && ctrl->opts->data_digest)
 		lim.features |= BLK_FEAT_STABLE_WRITES;
+	if (ctrl->ops->supports_pci_p2pdma &&
+	    ctrl->ops->supports_pci_p2pdma(ctrl))
+		lim.features |= BLK_FEAT_PCI_P2PDMA;
 
 	disk = blk_mq_alloc_disk(ctrl->tagset, &lim, ns);
 	if (IS_ERR(disk))
@@ -3744,11 +3747,6 @@ static void nvme_alloc_ns(struct nvme_ctrl *ctrl, struct nvme_ns_info *info)
 
 	ns->disk = disk;
 	ns->queue = disk->queue;
-
-	if (ctrl->ops->supports_pci_p2pdma &&
-	    ctrl->ops->supports_pci_p2pdma(ctrl))
-		blk_queue_flag_set(QUEUE_FLAG_PCI_P2PDMA, ns->queue);
-
 	ns->ctrl = ctrl;
 	kref_init(&ns->kref);
 
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index ffb7a42871b4ed..cc4f6e64e8e3f5 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -319,6 +319,9 @@ enum {
 
 	/* supports Zone Reset All */
 	BLK_FEAT_ZONE_RESETALL			= (1u << 11),
+
+	/* supports PCI(e) p2p requests */
+	BLK_FEAT_PCI_P2PDMA			= (1u << 12),
 };
 
 /*
@@ -588,7 +591,6 @@ struct request_queue {
 #define QUEUE_FLAG_STATS	20	/* track IO start and completion times */
 #define QUEUE_FLAG_REGISTERED	22	/* queue has been registered to a disk */
 #define QUEUE_FLAG_QUIESCED	24	/* queue has been quiesced */
-#define QUEUE_FLAG_PCI_P2PDMA	25	/* device supports PCI p2p requests */
 #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 */
@@ -611,8 +613,7 @@ bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q);
 #define blk_queue_zone_resetall(q)	\
 	((q)->limits.features & BLK_FEAT_ZONE_RESETALL)
 #define blk_queue_dax(q)	((q)->limits.features & BLK_FEAT_DAX)
-#define blk_queue_pci_p2pdma(q)	\
-	test_bit(QUEUE_FLAG_PCI_P2PDMA, &(q)->queue_flags)
+#define blk_queue_pci_p2pdma(q)	((q)->limits.features & BLK_FEAT_PCI_P2PDMA)
 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
 #define blk_queue_rq_alloc_time(q)	\
 	test_bit(QUEUE_FLAG_RQ_ALLOC_TIME, &(q)->queue_flags)
-- 
2.43.0