pipe: Pass argument of pipe_fcntl as int

The interface for fcntl expects the argument passed for the command
F_SETPIPE_SZ 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: 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]
Signed-off-by: Luca Vizzarro <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Christian Brauner <[e-mail]>

fs/pipe.c

···
  * Currently we rely on the pipe array holding a power-of-2 number
  * of pages. Returns 0 on error.
  */
-unsigned int round_pipe_size(unsigned long size)
+unsigned int round_pipe_size(unsigned int size)
 {
 	if (size > (1U << 31))
 		return 0;
···
  * Allocate a new array of pipe buffers and copy the info over. Returns the
  * pipe size if successful, or return -ERROR on error.
  */
-static long pipe_set_size(struct pipe_inode_info *pipe, unsigned long arg)
+static long pipe_set_size(struct pipe_inode_info *pipe, unsigned int arg)
 {
 	unsigned long user_bufs;
 	unsigned int nr_slots, size;
···
 	return pipe;
 }
 
-long pipe_fcntl(struct file *file, unsigned int cmd, unsigned long arg)
+long pipe_fcntl(struct file *file, unsigned int cmd, unsigned int arg)
 {
 	struct pipe_inode_info *pipe;
 	long ret;

include/linux/pipe_fs_i.h

···
 
 /* for F_SETPIPE_SZ and F_GETPIPE_SZ */
 int pipe_resize_ring(struct pipe_inode_info *pipe, unsigned int nr_slots);
-long pipe_fcntl(struct file *, unsigned int, unsigned long arg);
+long pipe_fcntl(struct file *, unsigned int, unsigned int arg);
 struct pipe_inode_info *get_pipe_info(struct file *file, bool for_splice);
 
 int create_pipe_files(struct file **, int);
-unsigned int round_pipe_size(unsigned long size);
+unsigned int round_pipe_size(unsigned int size);
 
 #endif