nvme-fabrics: fix kato initialization

Currently kato is initialized to NVME_DEFAULT_KATO for both
discovery & i/o controllers. This is a problem specifically
for non-persistent discovery controllers since it always ends
up with a non-zero kato value. Fix this by initializing kato
to zero instead, and ensuring various controllers are assigned
appropriate kato values as follows:

non-persistent controllers  - kato set to zero
persistent controllers      - kato set to NVMF_DEV_DISC_TMO
                              (or any positive int via nvme-cli)
i/o controllers             - kato set to NVME_DEFAULT_KATO
                              (or any positive int via nvme-cli)

Signed-off-by: Martin George <marting@netapp.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/fabrics.c

@@ -630,7 +630,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 	opts->queue_size = NVMF_DEF_QUEUE_SIZE;
 	opts->nr_io_queues = num_online_cpus();
 	opts->reconnect_delay = NVMF_DEF_RECONNECT_DELAY;
-	opts->kato = NVME_DEFAULT_KATO;
+	opts->kato = 0;
 	opts->duplicate_connect = false;
 	opts->fast_io_fail_tmo = NVMF_DEF_FAIL_FAST_TMO;
 	opts->hdr_digest = false;
@@ -893,6 +893,9 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 		opts->nr_write_queues = 0;
 		opts->nr_poll_queues = 0;
 		opts->duplicate_connect = true;
+	} else {
+		if (!opts->kato)
+			opts->kato = NVME_DEFAULT_KATO;
 	}
 	if (ctrl_loss_tmo < 0) {
 		opts->max_reconnects = -1;