fs/pipe.c: local vars have to match types of proper pipe_inode_info f…

…ields

head, tail, ring_size are declared as unsigned int, so all local variables
that operate with these fields have to be unsigned to avoid signed integer
overflow.

Right now, it isn't an issue because the maximum pipe size is limited by
1U<<31.

Link: https://lkml.kernel.org/r/20220106171946.36128-1-avagin@gmail.com
Signed-off-by: Andrei Vagin <avagin@gmail.com>
Suggested-by: Dmitry Safonov <0x7f454c46@gmail.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

fs/pipe.c

@@ -606,7 +606,7 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 static long pipe_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
 	struct pipe_inode_info *pipe = filp->private_data;
-	int count, head, tail, mask;
+	unsigned int count, head, tail, mask;
 
 	switch (cmd) {
 	case FIONREAD:
@@ -828,7 +828,7 @@ struct pipe_inode_info *alloc_pipe_info(void)
 
 void free_pipe_info(struct pipe_inode_info *pipe)
 {
-	int i;
+	unsigned int i;
 
 #ifdef CONFIG_WATCH_QUEUE
 	if (pipe->watch_queue) {