dnotify: Pass argument of fcntl_dirnotify as int

The interface for fcntl expects the argument passed for the command
F_DIRNOTIFY to be of type int. The current code wrongly treats it as
a long. In order to avoid access to undefined bits, we should explicitly
cast the argument to int.

Cc: Jan Kara <[e-mail]>
Cc: Amir Goldstein <[e-mail]>
Cc: Alexander Viro <[e-mail]>
Cc: Christian Brauner <[e-mail]>
Cc: Jeff Layton <[e-mail]>
Cc: Chuck Lever <[e-mail]>
Cc: Kevin Brodsky <[e-mail]>
Cc: Vincenzo Frascino <[e-mail]>
Cc: Szabolcs Nagy <[e-mail]>
Cc: "Theodore Ts'o" <[e-mail]>
Cc: David Laight <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Acked-by: Jan Kara <[e-mail]>
Signed-off-by: Luca Vizzarro <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Christian Brauner <[e-mail]>

fs/notify/dnotify/dnotify.c

···
 }
 
 /* this conversion is done only at watch creation */
-static __u32 convert_arg(unsigned long arg)
+static __u32 convert_arg(unsigned int arg)
 {
 	__u32 new_mask = FS_EVENT_ON_CHILD;
 
···
  * up here.  Allocate both a mark for fsnotify to add and a dnotify_struct to be
  * attached to the fsnotify_mark.
  */
-int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
+int fcntl_dirnotify(int fd, struct file *filp, unsigned int arg)
 {
 	struct dnotify_mark *new_dn_mark, *dn_mark;
 	struct fsnotify_mark *new_fsn_mark, *fsn_mark;

include/linux/dnotify.h

···
 			    FS_MOVED_FROM | FS_MOVED_TO)
 
 extern void dnotify_flush(struct file *, fl_owner_t);
-extern int fcntl_dirnotify(int, struct file *, unsigned long);
+extern int fcntl_dirnotify(int, struct file *, unsigned int);
 
 #else
 
···
 {
 }
 
-static inline int fcntl_dirnotify(int fd, struct file *filp, unsigned long arg)
+static inline int fcntl_dirnotify(int fd, struct file *filp, unsigned int arg)
 {
 	return -EINVAL;
 }