[PATCHv3 2/2] nvme: add support multipath passthrough iostats

[Keith Busch <kbusch@meta.com>]

From: Keith Busch <kbusch@kernel.org>

Don't skip the io accounting for passthrough commands if the user
enabled tracking these.

Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Nitesh Shetty <nj.shetty@samsung.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
---
 drivers/nvme/host/ioctl.c     | 9 +++++++++
 drivers/nvme/host/multipath.c | 5 ++++-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/ioctl.c b/drivers/nvme/host/ioctl.c
index 08889b20e5d8c..664216eece4a6 100644
--- a/drivers/nvme/host/ioctl.c
+++ b/drivers/nvme/host/ioctl.c
@@ -102,8 +102,17 @@ static struct request *nvme_alloc_user_request(struct request_queue *q,
 		struct nvme_command *cmd, blk_opf_t rq_flags,
 		blk_mq_req_flags_t blk_flags)
 {
+	struct nvme_ns *ns = q->queuedata;
 	struct request *req;
 
+	/*
+	 * The NVME_MPATH flag is set only for IO commands sent to a namespace
+	 * with a multipath enabled head. The request is not eligible for
+	 * failover as passthrough requests also append REQ_FAILFAST_DRIVER.
+	 */
+	if (ns && nvme_ns_head_multipath(ns->head))
+		rq_flags |= REQ_NVME_MPATH;
+
 	req = blk_mq_alloc_request(q, nvme_req_op(cmd) | rq_flags, blk_flags);
 	if (IS_ERR(req))
 		return req;
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index ff442bbf2937a..bca8e7c975190 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -175,9 +175,12 @@ void nvme_mpath_start_request(struct request *rq)
 		nvme_req(rq)->flags |= NVME_MPATH_CNT_ACTIVE;
 	}
 
-	if (!blk_queue_io_stat(disk->queue) || blk_rq_is_passthrough(rq) ||
+	if (!blk_queue_io_stat(disk->queue) ||
 	    (nvme_req(rq)->flags & NVME_MPATH_IO_STATS))
 		return;
+	if (blk_rq_is_passthrough(rq) &&
+	    !blk_rq_passthrough_stats(rq, disk->queue))
+		return;
 
 	nvme_req(rq)->flags |= NVME_MPATH_IO_STATS;
 	nvme_req(rq)->start_time = bdev_start_io_acct(disk->part0, req_op(rq),
-- 
2.53.0-Meta