sysfs: Only take active references on attributes.

If we exclude directories and symlinks from the set of sysfs
dirents where we need active references we are left with
sysfs attributes (binary or not).

- Tweak sysfs_deactivate to only do something on attributes
- Move lockdep initialization into sysfs_file_add_mode to
  limit it to just attributes.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

3 files changed, 6 insertions, 1 deletions

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 1bdc42f4fd93..481fdec09f4e 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -156,6 +156,10 @@ static void sysfs_deactivate(struct sysfs_dirent *sd)
         int v;
 
         BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
+
+        if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
+                return;
+
         sd->s_sibling = (void *)&wait;
 
         rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
@@ -315,7 +319,6 @@ struct sysfs_dirent *sysfs_new_dirent(const char *name, umode_t mode, int type)
 
         atomic_set(&sd->s_count, 1);
         atomic_set(&sd->s_active, 0);
-        sysfs_dirent_init_lockdep(sd);
 
         sd->s_name = name;
         sd->s_mode = mode;
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 40961366e929..e222b2582746 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -509,6 +509,7 @@ int sysfs_add_file_mode(struct sysfs_dirent *dir_sd,
         if (!sd)
                 return -ENOMEM;
         sd->s_attr.attr = (void *)attr;
+        sysfs_dirent_init_lockdep(sd);
 
         sysfs_addrm_start(&acxt, dir_sd);
         rc = sysfs_add_one(&acxt, sd);
diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index bb7723c4f5a5..7db6884f4206 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -79,6 +79,7 @@ struct sysfs_dirent {
 #define SYSFS_KOBJ_BIN_ATTR             0x0004
 #define SYSFS_KOBJ_LINK                 0x0008
 #define SYSFS_COPY_NAME                 (SYSFS_DIR | SYSFS_KOBJ_LINK)
+#define SYSFS_ACTIVE_REF                (SYSFS_KOBJ_ATTR | SYSFS_KOBJ_BIN_ATTR)
 
 #define SYSFS_FLAG_MASK                 ~SYSFS_TYPE_MASK
 #define SYSFS_FLAG_REMOVED              0x0200