From 9d44aba7e05ea84a3dd7192c97f561b962cac5b9 Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 30 Nov 2023 13:02:11 +1100 Subject: [PATCH] util: MAX_FROM_BITS() should be unsigned MAX_FROM_BITS() computes the maximum value representable in a number of bits. The expression for that is an unsigned value, but we explicitly cast it to a signed int. It looks like this is because one of the main users is for FD_REF_MAX, which is used to bound fd values, typically stored as a signed int. The value MAX_FROM_BITS() is calculating is naturally non-negative, though, so it makes more sense for it to be unsigned, and to move the case to the definition of FD_REF_MAX. Signed-off-by: David Gibson Signed-off-by: Stefano Brivio --- passt.h | 2 +- util.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/passt.h b/passt.h index 3f5dfb9..0fce637 100644 --- a/passt.h +++ b/passt.h @@ -87,7 +87,7 @@ union epoll_ref { struct { enum epoll_type type:8; #define FD_REF_BITS 24 -#define FD_REF_MAX MAX_FROM_BITS(FD_REF_BITS) +#define FD_REF_MAX ((int)MAX_FROM_BITS(FD_REF_BITS)) int32_t fd:FD_REF_BITS; union { union tcp_epoll_ref tcp; diff --git a/util.h b/util.h index 86f1a7e..53bb54b 100644 --- a/util.h +++ b/util.h @@ -43,7 +43,7 @@ #define ROUND_DOWN(x, y) ((x) & ~((y) - 1)) #define ROUND_UP(x, y) (((x) + (y) - 1) & ~((y) - 1)) -#define MAX_FROM_BITS(n) ((int)((1U << (n)) - 1)) +#define MAX_FROM_BITS(n) (((1U << (n)) - 1)) #define BIT(n) (1UL << (n)) #define BITMAP_BIT(n) (BIT((n) % (sizeof(long) * 8)))