[PATCH 1/3] nvmet: check for subsystem type in nvmet_find_get_subsys()

[Hannes Reinecke <hare@suse.de>]

When looking for a subsystem we have two ways of finding the
subsystem: either looking for the subsystem NQN itself, or check
the type of the subsystem when looking for a discovery controller.
This patch implements this check, and also moves the check for
the static discovery controller to the end such that we can
return unique discovery controllers.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/target/core.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index b0dc6230d1b9..83eba511d098 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1508,12 +1508,6 @@ static struct nvmet_subsys *nvmet_find_get_subsys(struct nvmet_port *port,
 	if (!port)
 		return NULL;
 
-	if (!strcmp(NVME_DISC_SUBSYS_NAME, subsysnqn)) {
-		if (!kref_get_unless_zero(&nvmet_disc_subsys->ref))
-			return NULL;
-		return nvmet_disc_subsys;
-	}
-
 	down_read(&nvmet_config_sem);
 	list_for_each_entry(p, &port->subsystems, entry) {
 		if (!strncmp(p->subsys->subsysnqn, subsysnqn,
@@ -1523,8 +1517,22 @@ static struct nvmet_subsys *nvmet_find_get_subsys(struct nvmet_port *port,
 			up_read(&nvmet_config_sem);
 			return p->subsys;
 		}
+		if (!strcmp(NVME_DISC_SUBSYS_NAME, subsysnqn) &&
+		    nvmet_is_disc_subsys(p->subsys)) {
+			if (!kref_get_unless_zero(&p->subsys->ref))
+				break;
+			up_read(&nvmet_config_sem);
+			return p->subsys;
+		}
 	}
 	up_read(&nvmet_config_sem);
+
+	if (!strcmp(NVME_DISC_SUBSYS_NAME, subsysnqn)) {
+		if (!kref_get_unless_zero(&nvmet_disc_subsys->ref))
+			return NULL;
+		return nvmet_disc_subsys;
+	}
+
 	return NULL;
 }
 
-- 
2.29.2