gfs2: Clean up freeing struct gfs2_sbd

Add a free_sbd function for freeing a struct gfs2_sbd.  Use that for
freeing a super-block descriptor, either directly or via kobject_put.
Free sd_lkstats inside the kobject release function: that way,
gfs2_put_super will no longer leak sd_lkstats.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

fs/gfs2/sys.c

@@ -301,7 +301,7 @@ static void gfs2_sbd_release(struct kobject *kobj)
 {
 	struct gfs2_sbd *sdp = container_of(kobj, struct gfs2_sbd, sd_kobj);
 
-	kfree(sdp);
+	free_sbd(sdp);
 }
 
 static struct kobj_type gfs2_ktype = {
@@ -679,7 +679,6 @@ fail_lock_module:
 fail_tune:
 	sysfs_remove_group(&sdp->sd_kobj, &tune_group);
 fail_reg:
-	free_percpu(sdp->sd_lkstats);
 	fs_err(sdp, "error %d adding sysfs files\n", error);
 	kobject_put(&sdp->sd_kobj);
 	sb->s_fs_info = NULL;