SYSFS: allow sysfs_create_link to create symlinks in the root of sysfs

This is needed to make the compatible link for /sys/block in the future.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 12 insertions, 2 deletions

diff --git a/fs/sysfs/symlink.c b/fs/sysfs/symlink.c
index d2eac3ceed5f..f50e3cc2ded8 100644
--- a/fs/sysfs/symlink.c
+++ b/fs/sysfs/symlink.c
@@ -3,6 +3,7 @@
  */
 
 #include <linux/fs.h>
+#include <linux/mount.h>
 #include <linux/module.h>
 #include <linux/kobject.h>
 #include <linux/namei.h>
@@ -82,10 +83,19 @@ exit1:
  */
 int sysfs_create_link(struct kobject * kobj, struct kobject * target, const char * name)
 {
-        struct dentry * dentry = kobj->dentry;
+        struct dentry *dentry = NULL;
         int error = -EEXIST;
 
-        BUG_ON(!kobj || !kobj->dentry || !name);
+        BUG_ON(!name);
+
+        if (!kobj) {
+                if (sysfs_mount && sysfs_mount->mnt_sb)
+                        dentry = sysfs_mount->mnt_sb->s_root;
+        } else
+                dentry = kobj->dentry;
+
+        if (!dentry)
+                return -EFAULT;
 
         mutex_lock(&dentry->d_inode->i_mutex);
         if (!sysfs_dirent_exist(dentry->d_fsdata, name))