This is an update to say that I've tested this patch and it works as expected.
When the controller returns a Command Interrupted status the request is avoids nvme_failover_req()
and goes down the nvme_retry_req() path where the CRD is implemented and the command is
retried after a delay.
If the controllers returns Command Interrupted too many times, and nvme_req(req)->retries
runs down, this results in a device resource error returned to the block layer. But I think we'll
have this problem with any error.
[Tue Dec 3 08:18:33 2019] print_req_error: device resource error, dev nvme0c0n1, sector 4610048
[Tue Dec 3 08:18:33 2019] print_req_error: device resource error, dev nvme0c0n1, sector 7112704
The alternative is to stop incrementing nvme_req(req)->retries in nvme_retry_req() when CRD is set.
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 24dc9ed1a11b..ec9794698a20 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -258,8 +258,8 @@ static void nvme_retry_req(struct request *req)
crd = (nvme_req(req)->status & NVME_SC_CRD) >> 11;
if (ns && crd)
delay = ns->ctrl->crdt[crd - 1] * 100;
-
- nvme_req(req)->retries++;
+ else
+ nvme_req(req)->retries++;
blk_mq_requeue_request(req, false);
blk_mq_delay_kick_requeue_list(req->q, delay);
}
Thoughts?
/John
On 11/27/19, 2:12 PM, "Meneghini, John" <John.Meneghini@xxxxxxxxxx> wrote:
From: John Meneghini <johnm@xxxxxxxxxx>
- Fixes bug in nvme_complete_rq logic introduced by
Enhanced Command Retry code. According to TP-4033
when ACRE is enabled the host needs to support
the Command Interrupted status.
- The current code interprets Command Interrupted status
as a BLK_STS_IOERR. This results in a controller reset
when REQ_NVME_MPATH is set; in nvme_failover_req.
Fixes: 49cd84b6f8b677e ("nvme: implement Enhanced Command Retry")
Signed-off-by: John Meneghini <johnm@xxxxxxxxxx>
Signed-off-by: Hannes Reinecke <hare@xxxxxxx>
---
drivers/nvme/host/core.c | 2 ++
include/linux/blk_types.h | 1 +
2 files changed, 3 insertions(+)
diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 9696404a6182..24dc9ed1a11b 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -230,6 +230,8 @@ static blk_status_t nvme_error_status(u16 status)
return BLK_STS_NEXUS;
case NVME_SC_HOST_PATH_ERROR:
return BLK_STS_TRANSPORT;
+ case NVME_SC_CMD_INTERRUPTED:
+ return BLK_STS_DEV_RESOURCE;
default:
return BLK_STS_IOERR;
}
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index d688b96d1d63..6efee8f1b91b 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -84,6 +84,7 @@ static inline bool blk_path_error(blk_status_t error)
case BLK_STS_NEXUS:
case BLK_STS_MEDIUM:
case BLK_STS_PROTECTION:
+ case BLK_STS_DEV_RESOURCE:
return false;
}
--
2.21.0
