dm mpath: rdac fix init race

Re-order the initialisation of dm-rdac to avoid registering the hw
handler before the workqueue has been initialised. Closes a race
that would potentially give an oops.

Signed-off-by: Bryn M. Reeves <breeves@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 8 insertions, 7 deletions

diff --git a/drivers/md/dm-mpath-rdac.c b/drivers/md/dm-mpath-rdac.c
index 16b161345775..e04eb5c697fb 100644
--- a/drivers/md/dm-mpath-rdac.c
+++ b/drivers/md/dm-mpath-rdac.c
@@ -664,20 +664,21 @@ static struct hw_handler_type rdac_handler = {
 
 static int __init rdac_init(void)
 {
-        int r = dm_register_hw_handler(&rdac_handler);
-
-        if (r < 0) {
-                DMERR("%s: register failed %d", RDAC_DM_HWH_NAME, r);
-                return r;
-        }
+        int r;
 
         rdac_wkqd = create_singlethread_workqueue("rdac_wkqd");
         if (!rdac_wkqd) {
                 DMERR("Failed to create workqueue rdac_wkqd.");
-                dm_unregister_hw_handler(&rdac_handler);
                 return -ENOMEM;
         }
 
+        r = dm_register_hw_handler(&rdac_handler);
+        if (r < 0) {
+                DMERR("%s: register failed %d", RDAC_DM_HWH_NAME, r);
+                destroy_workqueue(rdac_wkqd);
+                return r;
+        }
+
         DMINFO("%s: version %s loaded", RDAC_DM_HWH_NAME, RDAC_DM_HWH_VER);
         return 0;
 }