rationalise return value for ->hot_add_disk method.

For all array types but linear, ->hot_add_disk returns 1 on
success, 0 on failure.
For linear, it returns 0 on success and -errno on failure.

This doesn't cause a functional problem because the ->hot_add_disk
function of linear is used quite differently to the others.
However it is confusing.

So convert all to return 0 for success or -errno on failure
and fix call sites to match.

Signed-off-by: Neil Brown <neilb@suse.de>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/md/multipath.c b/drivers/md/multipath.c
index 4a1d714c048e..541cbe3414bd 100644
--- a/drivers/md/multipath.c
+++ b/drivers/md/multipath.c
@@ -281,7 +281,7 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
 {
         multipath_conf_t *conf = mddev->private;
         struct request_queue *q;
-        int found = 0;
+        int err = -EEXIST;
         int path;
         struct multipath_info *p;
         int first = 0;
@@ -312,11 +312,13 @@ static int multipath_add_disk(mddev_t *mddev, mdk_rdev_t *rdev)
                         rdev->raid_disk = path;
                         set_bit(In_sync, &rdev->flags);
                         rcu_assign_pointer(p->rdev, rdev);
-                        found = 1;
+                        err = 0;
+                        break;
                 }
 
         print_multipath_conf(conf);
-        return found;
+
+        return err;
 }
 
 static int multipath_remove_disk(mddev_t *mddev, int number)