1 files changed, 12 insertions, 0 deletions

diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 5e0e31cc46f5..9889e54e1f13 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -109,6 +109,17 @@ static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
         inode->i_ctime = iattr->ia_ctime;
 }
 
+
+/*
+ * sysfs has a different i_mutex lock order behavior for i_mutex than other
+ * filesystems; sysfs i_mutex is called in many places with subsystem locks
+ * held. At the same time, many of the VFS locking rules do not apply to
+ * sysfs at all (cross directory rename for example). To untangle this mess
+ * (which gives false positives in lockdep), we're giving sysfs inodes their
+ * own class for i_mutex.
+ */
+static struct lock_class_key sysfs_inode_imutex_key;
+
 struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent * sd)
 {
         struct inode * inode = new_inode(sysfs_sb);
@@ -118,6 +129,7 @@ struct inode * sysfs_new_inode(mode_t mode, struct sysfs_dirent * sd)
                 inode->i_mapping->a_ops = &sysfs_aops;
                 inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
                 inode->i_op = &sysfs_inode_operations;
+                lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
 
                 if (sd->s_iattr) {
                         /* sysfs_dirent has non-default attributes