Re: [PATCH net-next v2 1/2] u64_stats: Allow u64_stats_add() to accept s64
From: David Laight <hidden>
Date: 2026-01-25 22:38:15
Also in:
linux-arm-kernel, linux-mediatek, lkml
On Mon, 26 Jan 2026 06:07:49 +0800 David Yang [off-list ref] wrote:
The current u64_stats_add() accepts only unsigned long, which makes no sense as u64_stats_set() accepts u64 already, and causes unnecessary narrowing on 32-bit architectures.
Isn't is a chicken/egg? A value over 2^31 could just be a very large value that needs to be added. Where the add is being done 'just in time' so avoid overflow. David
quoted hunk ↗ jump to hunk
Moreover, since there's no u64_stats_sub(), users may be tempted to reuse it for decrements, which already happened on nft_counter_reset() in net/netfilter/nft_counter.c . Change to s64 to allow both positive and negative values. Signed-off-by: David Yang <mmyangfl@gmail.com> --- include/linux/u64_stats_sync.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)diff --git a/include/linux/u64_stats_sync.h b/include/linux/u64_stats_sync.h index 457879938fc1..e77f2b30bac7 100644 --- a/include/linux/u64_stats_sync.h +++ b/include/linux/u64_stats_sync.h@@ -84,7 +84,7 @@ static inline void u64_stats_set(u64_stats_t *p, u64 val) local64_set(&p->v, val); } -static inline void u64_stats_add(u64_stats_t *p, unsigned long val) +static inline void u64_stats_add(u64_stats_t *p, s64 val) { local64_add(val, &p->v); }@@ -125,7 +125,7 @@ static inline void u64_stats_set(u64_stats_t *p, u64 val) p->v = val; } -static inline void u64_stats_add(u64_stats_t *p, unsigned long val) +static inline void u64_stats_add(u64_stats_t *p, s64 val) { p->v += val; }