[PATCH] nvme-fabrics: allow to queue requests for live queues

[Sagi Grimberg]

Right now we are failing requests based on the controller
state (which is checked inline in nvmf_check_ready) however
we should definitely accept requests if the queue is live.

When entering controller reset, we transition the controller
into NVME_CTRL_RESETTING, and then return BLK_STS_RESOURCE for
non-mpath requests (have blk_noretry_request set).

This is also the case for NVME_REQ_USER for some reason, but
there shouldn't be any reason for us to reject this I/O in a
controller reset.

In a non-mpath setup, this means that the requests will simply
be requeued over and over forever not allowing the q_usage_counter
to drop its final reference, causing controller reset to hang
if running concurrently with heavy I/O.

While we are at it, remove the redundant NVME_CTRL_NEW case, which
should never see any I/O as it must first transition to
NVME_CTRL_CONNECTING.

Fixes: 35897b920c8a ("nvme-fabrics: fix and refine state checks in __nvmf_check_ready")
Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 drivers/nvme/host/fabrics.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 4ec4829d6233..2e7838f42e36 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -564,21 +564,13 @@ bool __nvmf_check_ready(struct nvme_ctrl *ctrl, struct request *rq,
 {
 	struct nvme_request *req = nvme_req(rq);
 
-	/*
-	 * If we are in some state of setup or teardown only allow
-	 * internally generated commands.
-	 */
-	if (!blk_rq_is_passthrough(rq) || (req->flags & NVME_REQ_USERCMD))
-		return false;
-
 	/*
 	 * Only allow commands on a live queue, except for the connect command,
 	 * which is require to set the queue live in the appropinquate states.
 	 */
 	switch (ctrl->state) {
-	case NVME_CTRL_NEW:
 	case NVME_CTRL_CONNECTING:
-		if (nvme_is_fabrics(req->cmd) &&
+		if (blk_rq_is_passthrough(rq) && nvme_is_fabrics(req->cmd) &&
 		    req->cmd->fabrics.fctype == nvme_fabrics_type_connect)
 			return true;
 		break;
-- 
2.25.1