dm mpath: check if scsi_dh module already loaded before trying to load

If the requested scsi_dh module is already loaded then skip request_module(). Multipath table loads can hang in an unnecessary __request_module. Reported-by: Ben Marzinski <[email protected]> Cc: [email protected] Signed-off-by: Mike Snitzer <[email protected]> Signed-off-by: Alasdair G Kergon <[email protected]>
mrcsosa · May 12, 2012 · 510193a · 510193a
1 parent 7cab8bf
commit 510193a
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
@@ -718,8 +718,8 @@ static int parse_hw_handler(struct dm_arg_set *as, struct multipath *m)
 		return 0;
 
 	m->hw_handler_name = kstrdup(dm_shift_arg(as), GFP_KERNEL);
-	request_module("scsi_dh_%s", m->hw_handler_name);
-	if (scsi_dh_handler_exist(m->hw_handler_name) == 0) {
+	if (!try_then_request_module(scsi_dh_handler_exist(m->hw_handler_name),
+				     "scsi_dh_%s", m->hw_handler_name)) {
 		ti->error = "unknown hardware handler type";
 		ret = -EINVAL;
 		goto fail;