git: 9491ea7c6822 - main - linuxkpi: Fix `atomic_long_sub()` overflow
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Date: Wed, 25 Jan 2023 21:39:04 UTC
The branch main has been updated by dumbbell (ports committer): URL: https://cgit.FreeBSD.org/src/commit/?id=9491ea7c68221ca7bc5e369ebb57660886ef1b13 commit 9491ea7c68221ca7bc5e369ebb57660886ef1b13 Author: Jean-Sébastien Pédron <dumbbell@FreeBSD.org> AuthorDate: 2023-01-15 14:56:48 +0000 Commit: Jean-Sébastien Pédron <dumbbell@FreeBSD.org> CommitDate: 2023-01-25 21:26:54 +0000 linuxkpi: Fix `atomic_long_sub()` overflow By (ab)using `atomic_long_add_return()`, `atomic_long_sub()` was making the atomic long overflow. Indeed the underlying FreeBSD atomic is based on an unsigned long. Reviewed by: manu Approved by: manu Differential Revision: https://reviews.freebsd.org/D38090 --- sys/compat/linuxkpi/common/include/asm/atomic-long.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/sys/compat/linuxkpi/common/include/asm/atomic-long.h b/sys/compat/linuxkpi/common/include/asm/atomic-long.h index f8bd9edfccf9..aeec6edd707d 100644 --- a/sys/compat/linuxkpi/common/include/asm/atomic-long.h +++ b/sys/compat/linuxkpi/common/include/asm/atomic-long.h @@ -41,7 +41,7 @@ typedef struct { } atomic_long_t; #define atomic_long_add(i, v) atomic_long_add_return((i), (v)) -#define atomic_long_sub(i, v) atomic_long_add_return(-(i), (v)) +#define atomic_long_sub(i, v) atomic_long_sub_return((i), (v)) #define atomic_long_inc_return(v) atomic_long_add_return(1, (v)) #define atomic_long_inc_not_zero(v) atomic_long_add_unless((v), 1, 0) @@ -51,6 +51,12 @@ atomic_long_add_return(long i, atomic_long_t *v) return i + atomic_fetchadd_long(&v->counter, i); } +static inline long +atomic_long_sub_return(long i, atomic_long_t *v) +{ + return atomic_fetchadd_long(&v->counter, -i) - i; +} + static inline void atomic_long_set(atomic_long_t *v, long i) {