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BUG/MINOR: threads: fix multiple use of argument inside HA_ATOMIC_UPDATE_{MIN,MAX}() 

Just like in previous patch, it happens that HA_ATOMIC_UPDATE_MIN() and
HA_ATOMIC_UPDATE_MAX() would evaluate the (val) argument up to 3 times.
However this time it affects both thread and non-thread versions. It's
strange because the copy was properly performed for the (new) argument
in order to avoid this. Anyway it was done for the "val" one as well.

A quick code inspection showed that this currently has no effect as
these macros are fairly limited in usage.

It would be best to backport this for long-term stability (till 1.8)
but it will not fix an existing bug.
This commit is contained in:
Willy Tarreau 2020-05-05 16:13:36 +02:00
parent d66345d6b0
commit a4d9ee3d1c
1 changed files with 16 additions and 12 deletions
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28
include/common/hathreads.h
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@ -135,20 +135,22 @@ extern THREAD_LOCAL struct thread_info *ti; /* thread_info for the current threa
#define HA_ATOMIC_STORE(val, new) ({*(val) = new;})
#define HA_ATOMIC_UPDATE_MAX(val, new) \
({ \
typeof(val) __val = (val); \
typeof(*(val)) __new_max = (new); \
\
if (*(val) < __new_max) \
*(val) = __new_max; \
*(val); \
if (*__val < __new_max) \
*__val = __new_max; \
*__val; \
})
#define HA_ATOMIC_UPDATE_MIN(val, new) \
({ \
typeof(val) __val = (val); \
typeof(*(val)) __new_min = (new); \
\
if (*(val) > __new_min) \
*(val) = __new_min; \
*(val); \
if (*__val > __new_min) \
*__val = __new_min; \
*__val; \
})
#define HA_BARRIER() do { } while (0)
@ -410,21 +412,23 @@ static inline unsigned long thread_isolated()
#define HA_ATOMIC_UPDATE_MAX(val, new) \
({ \
typeof(*(val)) __old_max = *(val); \
typeof(val) __val = (val); \
typeof(*(val)) __old_max = *__val; \
typeof(*(val)) __new_max = (new); \
\
while (__old_max < __new_max && \
!HA_ATOMIC_CAS(val, &__old_max, __new_max)); \
*(val); \
!HA_ATOMIC_CAS(__val, &__old_max, __new_max)); \
*__val; \
})
#define HA_ATOMIC_UPDATE_MIN(val, new) \
({ \
typeof(*(val)) __old_min = *(val); \
typeof(val) __val = (val); \
typeof(*(val)) __old_min = *__val; \
typeof(*(val)) __new_min = (new); \
\
while (__old_min > __new_min && \
!HA_ATOMIC_CAS(val, &__old_min, __new_min)); \
*(val); \
!HA_ATOMIC_CAS(__val, &__old_min, __new_min)); \
*__val; \
})
#define HA_BARRIER() pl_barrier()