sysfs, kernfs: revamp sysfs_dirent active_ref lockdep annotation

Currently, sysfs_dirent active_ref lockdep annotation uses
attribute->[s]key as the lockdep key, which forces
kernfs_create_file_ns() to assume that sysfs_dirent->priv is pointing
to a struct attribute which may not be true for non-sysfs users.  This
patch restructures the lockdep annotation such that

* kernfs_ops contains lockdep_key which is used by default for files
  created kernfs_create_file_ns().

* kernfs_create_file_ns_key() is introduced which takes an extra @key
  argument.  The created file will use the specified key for
  active_ref lockdep annotation.  If NULL is specified, lockdep for
  the file is disabled.

* sysfs_add_file_mode_ns() is updated to use
  kernfs_create_file_ns_key() with the appropriate key from the
  attribute or NULL if ignore_lockdep is set.

This makes the lockdep annotation properly contained in kernfs while
allowing sysfs to cleanly keep its current behavior.  This patch
doesn't introduce any behavior differences.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index e88e9a94a083..8f2d577b5f64 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -150,7 +150,7 @@ struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
         if (!atomic_inc_unless_negative(&sd->s_active))
                 return NULL;
 
-        if (likely(!sysfs_ignore_lockdep(sd)))
+        if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
                 rwsem_acquire_read(&sd->dep_map, 0, 1, _RET_IP_);
         return sd;
 }
@@ -169,7 +169,7 @@ void sysfs_put_active(struct sysfs_dirent *sd)
         if (unlikely(!sd))
                 return;
 
-        if (likely(!sysfs_ignore_lockdep(sd)))
+        if (sd->s_flags & SYSFS_FLAG_LOCKDEP)
                 rwsem_release(&sd->dep_map, 1, _RET_IP_);
         v = atomic_dec_return(&sd->s_active);
         if (likely(v != SD_DEACTIVATED_BIAS))