From 900ea8b46b7e978f55d61c5bdf0bef0f011972e7 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Mon, 15 Jun 2026 18:18:33 +1000 Subject: tcp: MAX_WINDOW should be unsigned Currently MAX_WINDOW is defined as a (signed) int, since '1' is a signed literal. This means that when it's used in the SEQ_*() macros, we're making a signed / unsigned comparison. While I don't think it was incorrect in practice, confirming that requires reasoning though arcane C type promotion rules. Since it's obviously a non-negative value, change the constant to unsigned. Change BUF_DISCARD_SIZE for the same reason, and because they're linked via DISCARD_IOV_NUM, which must also be non-negative. Change the types of a few variables in tcp_prepare_iov() to match (otherwise we'd get some compiler warnings). Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- tcp.c | 3 +-- tcp_internal.h | 4 ++-- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/tcp.c b/tcp.c index edcabe2..10d9d0d 100644 --- a/tcp.c +++ b/tcp.c @@ -4069,9 +4069,8 @@ int tcp_prepare_iov(struct msghdr *msg, struct iovec *iov, msg->msg_iov = iov + DISCARD_IOV_NUM; msg->msg_iovlen = payload_iov_cnt; } else { - int discard_cnt, discard_iov_rem; + unsigned discard_cnt, discard_iov_rem, i; struct iovec *iov_start; - int i; discard_cnt = DIV_ROUND_UP(already_sent, BUF_DISCARD_SIZE); if (discard_cnt > DISCARD_IOV_NUM) { diff --git a/tcp_internal.h b/tcp_internal.h index 40472c9..c623569 100644 --- a/tcp_internal.h +++ b/tcp_internal.h @@ -12,9 +12,9 @@ #include "util.h" #define MAX_WS 8 -#define MAX_WINDOW (1 << (16 + (MAX_WS))) +#define MAX_WINDOW (1U << (16 + (MAX_WS))) -#define BUF_DISCARD_SIZE (1 << 20) +#define BUF_DISCARD_SIZE (1U << 20) #define DISCARD_IOV_NUM DIV_ROUND_UP(MAX_WINDOW, BUF_DISCARD_SIZE) #define MSS4 ROUND_DOWN(IP_MAX_MTU - \ -- cgit v1.2.3