nvme-loop: add support for multiple ports

This is useful at least for multipath testing.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

drivers/nvme/target/loop.c

@@ -45,6 +45,7 @@ struct nvme_loop_ctrl {
 	struct nvme_ctrl	ctrl;
 
 	struct nvmet_ctrl	*target_ctrl;
+	struct nvmet_port	*port;
 };
 
 static inline struct nvme_loop_ctrl *to_loop_ctrl(struct nvme_ctrl *ctrl)
@@ -63,7 +64,8 @@ struct nvme_loop_queue {
 	unsigned long		flags;
 };
 
-static struct nvmet_port *nvmet_loop_port;
+static LIST_HEAD(nvme_loop_ports);
+static DEFINE_MUTEX(nvme_loop_ports_mutex);
 
 static LIST_HEAD(nvme_loop_ctrl_list);
 static DEFINE_MUTEX(nvme_loop_ctrl_mutex);
@@ -169,7 +171,7 @@ static blk_status_t nvme_loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 
 	blk_mq_start_request(req);
 	iod->cmd.common.flags |= NVME_CMD_SGL_METABUF;
-	iod->req.port = nvmet_loop_port;
+	iod->req.port = queue->ctrl->port;
 	if (!nvmet_req_init(&iod->req, &queue->nvme_cq,
 			&queue->nvme_sq, &nvme_loop_ops))
 		return BLK_STS_OK;
@@ -517,6 +519,7 @@ static const struct nvme_ctrl_ops nvme_loop_ctrl_ops = {
 	.free_ctrl		= nvme_loop_free_ctrl,
 	.submit_async_event	= nvme_loop_submit_async_event,
 	.delete_ctrl		= nvme_loop_delete_ctrl_host,
+	.get_address		= nvmf_get_address,
 };
 
 static int nvme_loop_create_io_queues(struct nvme_loop_ctrl *ctrl)
@@ -565,6 +568,23 @@ static int nvme_loop_create_io_queues(struct nvme_loop_ctrl *ctrl)
 	return ret;
 }
 
+static struct nvmet_port *nvme_loop_find_port(struct nvme_ctrl *ctrl)
+{
+	struct nvmet_port *p, *found = NULL;
+
+	mutex_lock(&nvme_loop_ports_mutex);
+	list_for_each_entry(p, &nvme_loop_ports, entry) {
+		/* if no transport address is specified use the first port */
+		if ((ctrl->opts->mask & NVMF_OPT_TRADDR) &&
+		    strcmp(ctrl->opts->traddr, p->disc_addr.traddr))
+			continue;
+		found = p;
+		break;
+	}
+	mutex_unlock(&nvme_loop_ports_mutex);
+	return found;
+}
+
 static struct nvme_ctrl *nvme_loop_create_ctrl(struct device *dev,
 		struct nvmf_ctrl_options *opts)
 {
@@ -589,6 +609,7 @@ static struct nvme_ctrl *nvme_loop_create_ctrl(struct device *dev,
 
 	ctrl->ctrl.sqsize = opts->queue_size - 1;
 	ctrl->ctrl.kato = opts->kato;
+	ctrl->port = nvme_loop_find_port(&ctrl->ctrl);
 
 	ctrl->queues = kcalloc(opts->nr_io_queues + 1, sizeof(*ctrl->queues),
 			GFP_KERNEL);
@@ -646,27 +667,17 @@ static struct nvme_ctrl *nvme_loop_create_ctrl(struct device *dev,
 
 static int nvme_loop_add_port(struct nvmet_port *port)
 {
-	/*
-	 * XXX: disalow adding more than one port so
-	 * there is no connection rejections when a
-	 * a subsystem is assigned to a port for which
-	 * loop doesn't have a pointer.
-	 * This scenario would be possible if we allowed
-	 * more than one port to be added and a subsystem
-	 * was assigned to a port other than nvmet_loop_port.
-	 */
-
-	if (nvmet_loop_port)
-		return -EPERM;
-
-	nvmet_loop_port = port;
+	mutex_lock(&nvme_loop_ports_mutex);
+	list_add_tail(&port->entry, &nvme_loop_ports);
+	mutex_unlock(&nvme_loop_ports_mutex);
 	return 0;
 }
 
 static void nvme_loop_remove_port(struct nvmet_port *port)
 {
-	if (port == nvmet_loop_port)
-		nvmet_loop_port = NULL;
+	mutex_lock(&nvme_loop_ports_mutex);
+	list_del_init(&port->entry);
+	mutex_unlock(&nvme_loop_ports_mutex);
 }
 
 static const struct nvmet_fabrics_ops nvme_loop_ops = {
@@ -682,6 +693,7 @@ static struct nvmf_transport_ops nvme_loop_transport = {
 	.name		= "loop",
 	.module		= THIS_MODULE,
 	.create_ctrl	= nvme_loop_create_ctrl,
+	.allowed_opts	= NVMF_OPT_TRADDR,
 };
 
 static int __init nvme_loop_init_module(void)

drivers/nvme/target/nvmet.h

@@ -85,7 +85,7 @@ struct nvmet_sq {
 /**
  * struct nvmet_port -	Common structure to keep port
  *				information for the target.
- * @entry:		List head for holding a list of these elements.
+ * @entry:		Entry into referrals or transport list.
  * @disc_addr:		Address information is stored in a format defined
  *				for a discovery log page entry.
  * @group:		ConfigFS group for this element's folder.