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-rw-r--r--fs/kernfs/file.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index f0cb729e9a..b7f943f333 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -447,7 +447,7 @@ static int kernfs_fop_mmap(struct file *file, struct vm_area_struct *vma)
* warnings and we don't want to add spurious locking dependency
* between the two. Check whether mmap is actually implemented
* without grabbing @of->mutex by testing HAS_MMAP flag. See the
- * comment in kernfs_file_open() for more details.
+ * comment in kernfs_fop_open() for more details.
*/
if (!(of->kn->flags & KERNFS_HAS_MMAP))
return -ENODEV;
@@ -634,11 +634,18 @@ static int kernfs_fop_open(struct inode *inode, struct file *file)
* each file a separate locking class. Let's differentiate on
* whether the file has mmap or not for now.
*
- * Both paths of the branch look the same. They're supposed to
+ * For similar reasons, writable and readonly files are given different
+ * lockdep key, because the writable file /sys/power/resume may call vfs
+ * lookup helpers for arbitrary paths and readonly files can be read by
+ * overlayfs from vfs helpers when sysfs is a lower layer of overalyfs.
+ *
+ * All three cases look the same. They're supposed to
* look that way and give @of->mutex different static lockdep keys.
*/
if (has_mmap)
mutex_init(&of->mutex);
+ else if (file->f_mode & FMODE_WRITE)
+ mutex_init(&of->mutex);
else
mutex_init(&of->mutex);