[PATCH V3 3/3] nvme: retry commands based on ACRE flag

[Minwoo Im]

Allow nvme_decide_disposition() to retry commands with error by checking
Advanced Command Retry Enable (ACRE) flag of controller first than
REQ_FAILFAST_* cmd_flags.  But, we just can't allow all command failures
to be retried due to reasons like connecting may take too long due to
the retries.  This patch only allows non-host path error commands to be
retried.

Cc: Chao Leng <lengchao at huawei.com>
Cc: Sagi Grimberg <sagi at grimberg.me>
Cc: Keith Busch <kbusch at kernel.org>
Signed-off-by: Minwoo Im <minwoo.im.dev at gmail.com>
---
 drivers/nvme/host/core.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index a286e3422c61..e4f7c49c2f39 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -303,8 +303,7 @@ 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) ||
-	    (nvme_req(req)->status & NVME_SC_DNR) ||
+	if ((nvme_req(req)->status & NVME_SC_DNR) ||
 	    nvme_req(req)->retries >= nvme_max_retries)
 		return COMPLETE;
 
@@ -317,6 +316,13 @@ static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
 			return COMPLETE;
 	}
 
+	if (nvme_req(req)->ctrl->acre &&
+	    !nvme_is_path_error(nvme_req(req)->status) &&
+	    !blk_queue_dying(req->q))
+		return RETRY;
+	else if (blk_noretry_request(req))
+		return COMPLETE;
+
 	return RETRY;
 }
 
-- 
2.17.1