[PATCH] md: get sysfs entry after redundancy attr group create

[Junxiao Bi]

"sync_completed" and "degraded" belongs to redundancy attr group,
it was not exist yet when md device was created.

Reported-by: kernel test robot <rong.a.c...@intel.com>
Fixes: e1a86dbbbd6a ("md: fix deadlock causing by sysfs_notify")
Signed-off-by: Junxiao Bi <junxiao...@oracle.com>
---
 drivers/md/md.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/md/md.c b/drivers/md/md.c
index fee8943ead7b..60d2142c4693 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -846,7 +846,13 @@ void mddev_unlock(struct mddev *mddev)
                                sysfs_remove_group(&mddev->kobj, 
&md_redundancy_group);
                                if (mddev->sysfs_action)
                                        sysfs_put(mddev->sysfs_action);
+                               if (mddev->sysfs_completed)
+                                       sysfs_put(mddev->sysfs_completed);
+                               if (mddev->sysfs_degraded)
+                                       sysfs_put(mddev->sysfs_degraded);
                                mddev->sysfs_action = NULL;
+                               mddev->sysfs_completed = NULL;
+                               mddev->sysfs_degraded = NULL;
                        }
                }
                mddev->sysfs_active = 0;
@@ -4036,6 +4042,8 @@ level_store(struct mddev *mddev, const char *buf, size_t 
len)
                        pr_warn("md: cannot register extra attributes for %s\n",
                                mdname(mddev));
                mddev->sysfs_action = sysfs_get_dirent(mddev->kobj.sd, 
"sync_action");
+               mddev->sysfs_completed = sysfs_get_dirent_safe(mddev->kobj.sd, 
"sync_completed");
+               mddev->sysfs_degraded = sysfs_get_dirent_safe(mddev->kobj.sd, 
"degraded");
        }
        if (oldpers->sync_request != NULL &&
            pers->sync_request == NULL) {
@@ -5542,14 +5550,9 @@ static void md_free(struct kobject *ko)
 
        if (mddev->sysfs_state)
                sysfs_put(mddev->sysfs_state);
-       if (mddev->sysfs_completed)
-               sysfs_put(mddev->sysfs_completed);
-       if (mddev->sysfs_degraded)
-               sysfs_put(mddev->sysfs_degraded);
        if (mddev->sysfs_level)
                sysfs_put(mddev->sysfs_level);
 
-
        if (mddev->gendisk)
                del_gendisk(mddev->gendisk);
        if (mddev->queue)
@@ -5710,8 +5713,6 @@ static int md_alloc(dev_t dev, char *name)
        if (!error && mddev->kobj.sd) {
                kobject_uevent(&mddev->kobj, KOBJ_ADD);
                mddev->sysfs_state = sysfs_get_dirent_safe(mddev->kobj.sd, 
"array_state");
-               mddev->sysfs_completed = sysfs_get_dirent_safe(mddev->kobj.sd, 
"sync_completed");
-               mddev->sysfs_degraded = sysfs_get_dirent_safe(mddev->kobj.sd, 
"degraded");
                mddev->sysfs_level = sysfs_get_dirent_safe(mddev->kobj.sd, 
"level");
        }
        mddev_put(mddev);
@@ -5991,6 +5992,8 @@ int md_run(struct mddev *mddev)
                        pr_warn("md: cannot register extra attributes for %s\n",
                                mdname(mddev));
                mddev->sysfs_action = sysfs_get_dirent_safe(mddev->kobj.sd, 
"sync_action");
+               mddev->sysfs_completed = sysfs_get_dirent_safe(mddev->kobj.sd, 
"sync_completed");
+               mddev->sysfs_degraded = sysfs_get_dirent_safe(mddev->kobj.sd, 
"degraded");
        } else if (mddev->ro == 2) /* auto-readonly not meaningful */
                mddev->ro = 0;
 
-- 
2.20.1 (Apple Git-117)