io_uring: fix types in io_recvmsg_multishot_overflow

io_recvmsg_multishot_overflow had incorrect types on non x64 system.
But also it had an unnecessary INT_MAX check, which could just be done
by changing the type of the accumulator to int (also simplifying the
casts).
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: a8b38c4ce724 ("io_uring: support multishot in recvmsg")
Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220715130252.610639-1-dylany@fb.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/net.c

@@ -327,14 +327,14 @@ int io_send(struct io_kiocb *req, unsigned int issue_flags)
 
 static bool io_recvmsg_multishot_overflow(struct io_async_msghdr *iomsg)
 {
-	unsigned long hdr;
+	int hdr;
 
-	if (check_add_overflow(sizeof(struct io_uring_recvmsg_out),
-			       (unsigned long)iomsg->namelen, &hdr))
+	if (iomsg->namelen < 0)
 		return true;
-	if (check_add_overflow(hdr, iomsg->controllen, &hdr))
+	if (check_add_overflow((int)sizeof(struct io_uring_recvmsg_out),
+			       iomsg->namelen, &hdr))
 		return true;
-	if (hdr > INT_MAX)
+	if (check_add_overflow(hdr, (int)iomsg->controllen, &hdr))
 		return true;
 
 	return false;