[PATCH 3/3] block: warn if ->groups is set when calling add_disk

[Christoph Hellwig]

The proper API is to pass the groups to device_add_disk, but the code
used to also allow groups being set before calling *add_disk.  Warn
about that but keep the group pointer intact for now so that it can
be removed again after a grace period.

Fixes: 52b85909f85d ("block: fold register_disk into device_add_disk")
Signed-off-by: Christoph Hellwig <h...@lst.de>
Reviewed-by: Ira Weiny <ira.we...@intel.com>
Reviewed-by: Dan Williams <dan.j.willi...@intel.com>
---
 block/genhd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/genhd.c b/block/genhd.c
index 7b6e5e1cf9564..409cf608cc5bd 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -439,7 +439,8 @@ int device_add_disk(struct device *parent, struct gendisk 
*disk,
        dev_set_uevent_suppress(ddev, 1);
 
        ddev->parent = parent;
-       ddev->groups = groups;
+       if (!WARN_ON_ONCE(ddev->groups))
+               ddev->groups = groups;
        dev_set_name(ddev, "%s", disk->disk_name);
        if (!(disk->flags & GENHD_FL_HIDDEN))
                ddev->devt = MKDEV(disk->major, disk->first_minor);
-- 
2.30.2