From: Mike Snitzer <snitzer@xxxxxxxxxx>
nvme: allow local retry and proper failover for REQ_FAILFAST_TRANSPORT
BZ: 1948690
Upstream Status: RHEL-only
This commit offers a more minimalist version of these 2 rhel-8.git commits:
f8fb6ea1226e2 [nvme] nvme: update failover handling to work with REQ_FAILFAST_TRANSPORT
7dadadb072515 [nvme] nvme: allow retry for requests with REQ_FAILFAST_TRANSPORT set
REQ_FAILFAST_TRANSPORT is set by upper layer software that handles
multipathing. Unlike SCSI, NVMe's error handling was specifically
designed to handle local retry for non-path errors. As such, allow
NVMe's local retry mechanism to be used for requests marked with
REQ_FAILFAST_TRANSPORT.
In this way, the mechanism of NVMe multipath or other multipath are
now equivalent. The mechanism is: non path related error will be
retried locally, path related error is handled by multipath.
Also, introduce FAILUP handling for REQ_FAILFAST_TRANSPORT. Update
NVMe to allow failover of requests marked with either REQ_NVME_MPATH
or REQ_FAILFAST_TRANSPORT. This allows such requests to be given a
disposition of either FAILOVER or FAILUP respectively.
nvme_complete_rq() is updated to call nvme_failup_req() if
nvme_decide_disposition() returns FAILUP. nvme_failup_req() ensures
the request is completed with a retryable path error.
Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
diff a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -299,6 +299,7 @@ enum nvme_disposition {
COMPLETE,
RETRY,
FAILOVER,
+ FAILUP,
};
static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
@@ -306,15 +307,16 @@ static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
if (likely(nvme_req(req)->status == 0))
return COMPLETE;
- if (blk_noretry_request(req) ||
+ if ((req->cmd_flags & (REQ_FAILFAST_DEV | REQ_FAILFAST_DRIVER)) ||
(nvme_req(req)->status & NVME_SC_DNR) ||
nvme_req(req)->retries >= nvme_max_retries)
return COMPLETE;
- if (req->cmd_flags & REQ_NVME_MPATH) {
+ if (req->cmd_flags & (REQ_NVME_MPATH | REQ_FAILFAST_TRANSPORT)) {
if (nvme_is_path_error(nvme_req(req)->status) ||
blk_queue_dying(req->q))
- return FAILOVER;
+ return (req->cmd_flags & REQ_NVME_MPATH) ?
+ FAILOVER : FAILUP;
} else {
if (blk_queue_dying(req->q))
return COMPLETE;
@@ -336,6 +338,12 @@ static inline void nvme_end_req(struct request *req)
blk_mq_end_request(req, status);
}
+static inline void nvme_failup_req(struct request *req)
+{
+ nvme_req(req)->status = NVME_SC_HOST_PATH_ERROR;
+ nvme_end_req(req);
+}
+
void nvme_complete_rq(struct request *req)
{
trace_nvme_complete_rq(req);
@@ -354,6 +362,9 @@ void nvme_complete_rq(struct request *req)
case FAILOVER:
nvme_failover_req(req);
return;
+ case FAILUP:
+ nvme_failup_req(req);
+ return;
}
}
EXPORT_SYMBOL_GPL(nvme_complete_rq);
--
https://gitlab.com/cki-project/kernel-ark/-/merge_requests/1024
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