[PATCH 1/3] nvmet: make the subsystem type configurable

[Hannes Reinecke]

Make the subsystem type configurable to allow for unique
discovery subsystems by changing the subsystem type to
'discovery'.

Signed-off-by: Hannes Reinecke <hare at suse.de>
---
 drivers/nvme/target/configfs.c  | 60 +++++++++++++++++++++++++++++++++
 drivers/nvme/target/discovery.c |  2 +-
 drivers/nvme/target/nvmet.h     |  1 +
 3 files changed, 62 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index e44b2988759e..38b0ab9fb721 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -834,6 +834,7 @@ static int nvmet_port_subsys_allow_link(struct config_item *parent,
 	}
 
 	list_add_tail(&link->entry, &port->subsystems);
+	subsys->port_count++;
 	nvmet_port_disc_changed(port, subsys);
 
 	up_write(&nvmet_config_sem);
@@ -862,6 +863,7 @@ static void nvmet_port_subsys_drop_link(struct config_item *parent,
 
 found:
 	list_del(&p->entry);
+	subsys->port_count--;
 	nvmet_port_del_ctrls(port, subsys);
 	nvmet_port_disc_changed(port, subsys);
 
@@ -1234,6 +1236,63 @@ static ssize_t nvmet_subsys_attr_model_store(struct config_item *item,
 }
 CONFIGFS_ATTR(nvmet_subsys_, attr_model);
 
+static const struct nvmet_type_name_map nvmet_subsys_type_map[] = {
+	{ NVME_NQN_DISC,	"referral" },
+	{ NVME_NQN_NVME,	"nvme" },
+	{ NVME_NQN_CURR,	"discovery" },
+};
+
+static ssize_t nvmet_subsys_attr_type_show(struct config_item *item,
+						 char *page)
+{
+	u8 type = to_subsys(item)->type;
+	int i;
+
+	for (i = 1; i < ARRAY_SIZE(nvmet_subsys_type_map); i++) {
+		if (nvmet_subsys_type_map[i].type == type)
+			return snprintf(page, PAGE_SIZE, "%s\n",
+					nvmet_subsys_type_map[i].name);
+	}
+
+	return snprintf(page, PAGE_SIZE, "\n");
+}
+
+static ssize_t nvmet_subsys_attr_type_store(struct config_item *item,
+					    const char *page, size_t count)
+{
+	struct nvmet_subsys *subsys = to_subsys(item);
+	int i;
+
+	if (subsys->subsys_discovered)
+		return -EACCES;
+
+	for (i = 0; i < ARRAY_SIZE(nvmet_subsys_type_map); i++) {
+		if (sysfs_streq(page, nvmet_subsys_type_map[i].name))
+			goto found;
+	}
+
+	pr_err("Invalid value '%s' for subsystem type\n", page);
+	return -EINVAL;
+
+found:
+	down_write(&nvmet_config_sem);
+	if (subsys->port_count) {
+		pr_err("cannot change type when linked to ports\n");
+		up_write(&nvmet_config_sem);
+		return -EACCES;
+	}
+	if (!xa_empty(&subsys->namespaces)) {
+		pr_err("cannot change type when namespaces are configured\n");
+		up_write(&nvmet_config_sem);
+		return -EACCES;
+	}
+	subsys->type = nvmet_subsys_type_map[i].type;
+	up_write(&nvmet_config_sem);
+
+	return count;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_type);
+
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 static ssize_t nvmet_subsys_attr_pi_enable_show(struct config_item *item,
 						char *page)
@@ -1263,6 +1322,7 @@ static struct configfs_attribute *nvmet_subsys_attrs[] = {
 	&nvmet_subsys_attr_attr_cntlid_min,
 	&nvmet_subsys_attr_attr_cntlid_max,
 	&nvmet_subsys_attr_attr_model,
+	&nvmet_subsys_attr_attr_type,
 #ifdef CONFIG_BLK_DEV_INTEGRITY
 	&nvmet_subsys_attr_attr_pi_enable,
 #endif
diff --git a/drivers/nvme/target/discovery.c b/drivers/nvme/target/discovery.c
index c2162eef8ce1..b5012df790d5 100644
--- a/drivers/nvme/target/discovery.c
+++ b/drivers/nvme/target/discovery.c
@@ -219,7 +219,7 @@ static void nvmet_execute_disc_get_log_page(struct nvmet_req *req)
 
 		nvmet_format_discovery_entry(hdr, req->port,
 				p->subsys->subsysnqn, traddr,
-				NVME_NQN_NVME, numrec);
+				p->subsys->type, numrec);
 		numrec++;
 	}
 
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 69818752a33a..ecba3890ce65 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -216,6 +216,7 @@ struct nvmet_subsys {
 
 	struct mutex		lock;
 	struct kref		ref;
+	unsigned int		port_count;
 
 	struct xarray		namespaces;
 	unsigned int		nr_namespaces;
-- 
2.29.2