nvme: Use non zero KATO for persistent discovery connections

The NVMe Base Specification 2.1 states that:

"""
A host requests an explicit persistent connection ... by specifying a
non-zero Keep Alive Timer value in the Connect command.
"""

As such if we are starting a persistent connection to a discovery
controller and the KATO is currently 0 we need to update KATO to a non
zero value to avoid continuous timeouts on the target.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index a46f0f2d1c377b404f7d58c4a01a78995c70c811..42c5f05680f1f752dbc54067c2b3d54b62db67a6 100644 (file)
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -4991,8 +4991,14 @@ void nvme_start_ctrl(struct nvme_ctrl *ctrl)
         * checking that they started once before, hence are reconnecting back.
         */
        if (test_bit(NVME_CTRL_STARTED_ONCE, &ctrl->flags) &&
-           nvme_discovery_ctrl(ctrl))
+           nvme_discovery_ctrl(ctrl)) {
+               if (!ctrl->kato) {
+                       nvme_stop_keep_alive(ctrl);
+                       ctrl->kato = NVME_DEFAULT_KATO;
+                       nvme_start_keep_alive(ctrl);
+               }
                nvme_change_uevent(ctrl, "NVME_EVENT=rediscover");
+       }
 
        if (ctrl->queue_count > 1) {
                nvme_queue_scan(ctrl);