md: reduce dependence on sysfs.

We will want md devices to live as dm targets where sysfs is not
visible.  So allow md to not connect to sysfs.

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

1 files changed, 12 insertions, 0 deletions

diff --git a/drivers/md/md.h b/drivers/md/md.h
index 10597bfec000..1e6405918eec 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -382,6 +382,18 @@ struct md_sysfs_entry {
 };
 extern struct attribute_group md_bitmap_group;
 
+static inline struct sysfs_dirent *sysfs_get_dirent_safe(struct sysfs_dirent *sd, char *name)
+{
+        if (sd)
+                return sysfs_get_dirent(sd, NULL, name);
+        return sd;
+}
+static inline void sysfs_notify_dirent_safe(struct sysfs_dirent *sd)
+{
+        if (sd)
+                sysfs_notify_dirent(sd);
+}
+
 static inline char * mdname (mddev_t * mddev)
 {
         return mddev->gendisk ? mddev->gendisk->disk_name : "mdX";