[PATCH AUTOSEL 5.10 37/39] nvmet: fix false keep-alive timeout when a controller is torn down

From: Sasha Levin
Date: Thu Jun 03 2021 - 13:11:21 EST


From: Sagi Grimberg <sagi@xxxxxxxxxxx>

[ Upstream commit aaeadd7075dc9e184bc7876e9dd7b3bada771df2 ]

Controller teardown flow may take some time in case it has many I/O
queues, and the host may not send us keep-alive during this period.
Hence reset the traffic based keep-alive timer so we don't trigger
a controller teardown as a result of a keep-alive expiration.

Reported-by: Yi Zhang <yi.zhang@xxxxxxxxxx>
Signed-off-by: Sagi Grimberg <sagi@xxxxxxxxxxx>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
Reviewed-by: Hannes Reinecke <hare@xxxxxxx>
Tested-by: Yi Zhang <yi.zhang@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/nvme/target/core.c | 15 +++++++++++----
drivers/nvme/target/nvmet.h | 2 +-
2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 46e4f7ea34c8..a65a4a810654 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -379,10 +379,10 @@ static void nvmet_keep_alive_timer(struct work_struct *work)
{
struct nvmet_ctrl *ctrl = container_of(to_delayed_work(work),
struct nvmet_ctrl, ka_work);
- bool cmd_seen = ctrl->cmd_seen;
+ bool reset_tbkas = ctrl->reset_tbkas;

- ctrl->cmd_seen = false;
- if (cmd_seen) {
+ ctrl->reset_tbkas = false;
+ if (reset_tbkas) {
pr_debug("ctrl %d reschedule traffic based keep-alive timer\n",
ctrl->cntlid);
schedule_delayed_work(&ctrl->ka_work, ctrl->kato * HZ);
@@ -792,6 +792,13 @@ void nvmet_sq_destroy(struct nvmet_sq *sq)
percpu_ref_exit(&sq->ref);

if (ctrl) {
+ /*
+ * The teardown flow may take some time, and the host may not
+ * send us keep-alive during this period, hence reset the
+ * traffic based keep-alive timer so we don't trigger a
+ * controller teardown as a result of a keep-alive expiration.
+ */
+ ctrl->reset_tbkas = true;
nvmet_ctrl_put(ctrl);
sq->ctrl = NULL; /* allows reusing the queue later */
}
@@ -942,7 +949,7 @@ bool nvmet_req_init(struct nvmet_req *req, struct nvmet_cq *cq,
}

if (sq->ctrl)
- sq->ctrl->cmd_seen = true;
+ sq->ctrl->reset_tbkas = true;

return true;

diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index ea96487b5424..4bf6d21290c2 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -166,7 +166,7 @@ struct nvmet_ctrl {
struct nvmet_subsys *subsys;
struct nvmet_sq **sqs;

- bool cmd_seen;
+ bool reset_tbkas;

struct mutex lock;
u64 cap;
--
2.30.2