nvme-fabrics: protect against module unload during create_ctrl

NVMe transport driver module unload may (and usually does) trigger
iteration over the active controllers and delete them all (sometimes
under a mutex).  However, a controller can be created concurrently with
module unload which can lead to leakage of resources (most important char
device node leakage) in case the controller creation occured after the
unload delete and drain sequence.  To protect against this, we take a
module reference to guarantee that the nvme transport driver is not
unloaded while creating a controller.

Signed-off-by: Roy Shterman <roys@lightbitslabs.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index 1e21b286f299..fdfcc961029f 100644
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -686,6 +686,7 @@ static struct nvmet_fabrics_ops nvme_loop_ops = {
 
 static struct nvmf_transport_ops nvme_loop_transport = {
 	.name		= "loop",
+	.module		= THIS_MODULE,
 	.create_ctrl	= nvme_loop_create_ctrl,
 };