sysfs: Simplify sysfs_chmod_file semantics

Currently every caller of sysfs_chmod_file happens at either
file creation time to set a non-default mode or in response
to a specific user requested space change in policy.  Making
timestamps of when the chmod happens and notification of
a file changing mode uninteresting.

Remove the unnecessary time stamp and filesystem change
notification, and removes the last of the explicit inotify
and donitfy support from sysfs.
Acked-by: NTejun Heo <tj@kernel.org>
Acked-by: NSerge Hallyn <serue@us.ibm.com>
Signed-off-by: NEric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

fs/sysfs/file.c

@@ -604,17 +604,9 @@ int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
 	mutex_lock(&inode->i_mutex);
 
 	newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
-	newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
-	newattrs.ia_ctime = current_fs_time(inode->i_sb);
+	newattrs.ia_valid = ATTR_MODE;
 	rc = sysfs_setattr(victim, &newattrs);
 
-	if (rc == 0) {
-		fsnotify_change(victim, newattrs.ia_valid);
-		mutex_lock(&sysfs_mutex);
-		victim_sd->s_mode = newattrs.ia_mode;
-		mutex_unlock(&sysfs_mutex);
-	}
-
 	mutex_unlock(&inode->i_mutex);
  out:
 	dput(victim);