[PATCH v2] nbd: automatically load module on genl access

[Thomas Weißschuh]

Instead of forcing the user to manually load the module do it
automatically.

For example this avoids the following error when using nbd-client:

$ nbd-client localhost 10809 /dev/nbd0
...
Error: Couldn't resolve the nbd netlink family, make sure the nbd module is loaded and your nbd driver supports the netlink interface.

Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
Changes in v2:
- Expand Cc list to get some reviews
- Add concrete commit example to commit message
- Link to v1: https://lore.kernel.org/lkml/20221110052438.2188-1-linux@xxxxxxxxxxxxxx/
---
 drivers/block/nbd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 65ecde3e2a5b..8632dbacd2ef 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -2335,6 +2335,7 @@ static struct genl_family nbd_genl_family __ro_after_init = {
 	.mcgrps		= nbd_mcast_grps,
 	.n_mcgrps	= ARRAY_SIZE(nbd_mcast_grps),
 };
+MODULE_ALIAS_GENL_FAMILY(NBD_GENL_FAMILY_NAME);
 
 static int populate_nbd_status(struct nbd_device *nbd, struct sk_buff *reply)
 {

---
base-commit: f1fcbaa18b28dec10281551dfe6ed3a3ed80e3d6
change-id: 20230223-b4-nbd-genl-3a74ca638686

Best regards,
-- 
Thomas Weißschuh <linux@xxxxxxxxxxxxxx>