Re: [PATCH 1/1] nvme-multipath: Skip nr_active increments in RETRY disposition

[Keith Busch]

On Wed, Sep 24, 2025 at 03:43:18PM -0700, Amit Chaudhary wrote:
>  static inline void nvme_start_request(struct request *rq)
>  {
> -	if (rq->cmd_flags & REQ_NVME_MPATH)
> +	if ((rq->cmd_flags & REQ_NVME_MPATH) && (!nvme_req(rq)->retries))
>  		nvme_mpath_start_request(rq);
>  	blk_mq_start_request(rq);
>  }

Using "retries" is bit indirect as a proxy for multipath active counts.
Could this be moved to the mpath start instead, directly using the flag
that accounts for the path? This also helps to keep track if the command
gets retried across a user toggling the policy to "qd".

---
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index 3da980dc60d91..1c630967ddd40 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -182,7 +182,8 @@ void nvme_mpath_start_request(struct request *rq)
        struct nvme_ns *ns = rq->q->queuedata;
        struct gendisk *disk = ns->head->disk;

-       if (READ_ONCE(ns->head->subsys->iopolicy) == NVME_IOPOLICY_QD) {
+       if (READ_ONCE(ns->head->subsys->iopolicy) == NVME_IOPOLICY_QD &&
+           !(nvme_req(rq)->flags & NVME_MPATH_CNT_ACTIVE)) {
                atomic_inc(&ns->ctrl->nr_active);
                nvme_req(rq)->flags |= NVME_MPATH_CNT_ACTIVE;
        }
--