nvme-fabrics: allow duplicate connections to the discovery controller

The whole point of the discovery controller is that it can accept
multiple connections. Additionally the cmic field is not even defined for
the discovery controller identify page.
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/core.c

@@ -2184,7 +2184,8 @@ static int nvme_init_subsystem(struct nvme_ctrl *ctrl, struct nvme_id_ctrl *id)
 		 * Verify that the subsystem actually supports multiple
 		 * controllers, else bail out.
 		 */
-		if (nvme_active_ctrls(found) && !(id->cmic & (1 << 1))) {
+		if (!ctrl->opts->discovery_nqn &&
+		    nvme_active_ctrls(found) && !(id->cmic & (1 << 1))) {
 			dev_err(ctrl->device,
 				"ignoring ctrl due to duplicate subnqn (%s).\n",
 				found->subnqn);

drivers/nvme/host/fabrics.c

@@ -850,6 +850,7 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 	if (opts->discovery_nqn) {
 		opts->kato = 0;
 		opts->nr_io_queues = 0;
+		opts->duplicate_connect = true;
 	}
 	if (ctrl_loss_tmo < 0)
 		opts->max_reconnects = -1;