VERIFY_OCTAL_PERMISSIONS: stricter checking for sysfs perms.

Summary of http://lkml.org/lkml/2014/3/14/363 :

  Ted: module_param(queue_depth, int, 444)
  Joe: 0444!
  Rusty: User perms >= group perms >= other perms?
  Joe: CLASS_ATTR, DEVICE_ATTR, SENSOR_ATTR and SENSOR_ATTR_2?

Side effect of stricter permissions means removing the unnecessary
S_IFREG from several callers.

Note that the BUILD_BUG_ON_ZERO((perm) & 2) test was removed: a fair
number of drivers fail this test, so that will be the debate for a
future patch.

Suggested-by: Joe Perches <joe@perches.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> for drivers/pci/slot.c
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Mark Fasheh <mfasheh@suse.com>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
diff --git a/fs/ocfs2/stackglue.c b/fs/ocfs2/stackglue.c
index 1324e66..25e9f7b 100644
--- a/fs/ocfs2/stackglue.c
+++ b/fs/ocfs2/stackglue.c
@@ -494,7 +494,7 @@
 }
 
 static struct kobj_attribute ocfs2_attr_max_locking_protocol =
-	__ATTR(max_locking_protocol, S_IFREG | S_IRUGO,
+	__ATTR(max_locking_protocol, S_IRUGO,
 	       ocfs2_max_locking_protocol_show, NULL);
 
 static ssize_t ocfs2_loaded_cluster_plugins_show(struct kobject *kobj,
@@ -526,7 +526,7 @@
 }
 
 static struct kobj_attribute ocfs2_attr_loaded_cluster_plugins =
-	__ATTR(loaded_cluster_plugins, S_IFREG | S_IRUGO,
+	__ATTR(loaded_cluster_plugins, S_IRUGO,
 	       ocfs2_loaded_cluster_plugins_show, NULL);
 
 static ssize_t ocfs2_active_cluster_plugin_show(struct kobject *kobj,
@@ -548,7 +548,7 @@
 }
 
 static struct kobj_attribute ocfs2_attr_active_cluster_plugin =
-	__ATTR(active_cluster_plugin, S_IFREG | S_IRUGO,
+	__ATTR(active_cluster_plugin, S_IRUGO,
 	       ocfs2_active_cluster_plugin_show, NULL);
 
 static ssize_t ocfs2_cluster_stack_show(struct kobject *kobj,
@@ -597,7 +597,7 @@
 
 
 static struct kobj_attribute ocfs2_attr_cluster_stack =
-	__ATTR(cluster_stack, S_IFREG | S_IRUGO | S_IWUSR,
+	__ATTR(cluster_stack, S_IRUGO | S_IWUSR,
 	       ocfs2_cluster_stack_show,
 	       ocfs2_cluster_stack_store);