From 510193a2d3d2e03ae53b95c0ae4f33cdff02cbf8 Mon Sep 17 00:00:00 2001
From: Mike Snitzer <snitzer@redhat.com>
Date: Sat, 12 May 2012 01:43:21 +0100
Subject: [PATCH] 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 <bmarzins@redhat.com>
Cc: stable@kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
---
drivers/md/dm-mpath.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/md/dm-mpath.c b/drivers/md/dm-mpath.c
index 922a3385eead41..754f38f8a6922d 100644
--- 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;
--
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