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linux: try preadv64/pwritev64 before preadv/pwritev (#4683)

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Fixes: https://github.com/libuv/libuv/issues/4678
Refs: https://github.com/libuv/libuv/issues/4532
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Ben Noordhuis 2025-01-28 09:27:58 +01:00 committed by GitHub
parent 82351168b3
commit a6ddf41edf
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GPG Key ID: B5690EEEBB952194
1 changed files with 7 additions and 10 deletions
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17
src/unix/fs.c
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@ -461,12 +461,7 @@ static ssize_t uv__pwritev_emul(int fd,
/* The function pointer cache is an uintptr_t because _Atomic void* /* The function pointer cache is an uintptr_t because _Atomic void*
* doesn't work on macos/ios/etc... * doesn't work on macos/ios/etc...
* Disable optimization on armv7 to work around the bug described in
* https://github.com/libuv/libuv/issues/4532
*/ */
#if defined(__arm__) && (__ARM_ARCH == 7)
__attribute__((optimize("O0")))
#endif
static ssize_t uv__preadv_or_pwritev(int fd, static ssize_t uv__preadv_or_pwritev(int fd,
const struct iovec* bufs, const struct iovec* bufs,
size_t nbufs, size_t nbufs,
@ -479,7 +474,12 @@ static ssize_t uv__preadv_or_pwritev(int fd,
p = (void*) atomic_load_explicit(cache, memory_order_relaxed); p = (void*) atomic_load_explicit(cache, memory_order_relaxed);
if (p == NULL) { if (p == NULL) {
#ifdef RTLD_DEFAULT #ifdef RTLD_DEFAULT
p = dlsym(RTLD_DEFAULT, is_pread ? "preadv" : "pwritev"); /* Try _LARGEFILE_SOURCE version of preadv/pwritev first,
* then fall back to the plain version, for libcs like musl.
*/
p = dlsym(RTLD_DEFAULT, is_pread ? "preadv64" : "pwritev64");
if (p == NULL)
p = dlsym(RTLD_DEFAULT, is_pread ? "preadv" : "pwritev");
dlerror(); /* Clear errors. */ dlerror(); /* Clear errors. */
#endif /* RTLD_DEFAULT */ #endif /* RTLD_DEFAULT */
if (p == NULL) if (p == NULL)
@ -487,10 +487,7 @@ static ssize_t uv__preadv_or_pwritev(int fd,
atomic_store_explicit(cache, (uintptr_t) p, memory_order_relaxed); atomic_store_explicit(cache, (uintptr_t) p, memory_order_relaxed);
} }
/* Use memcpy instead of `f = p` to work around a compiler bug, f = p;
* see https://github.com/libuv/libuv/issues/4532
*/
memcpy(&f, &p, sizeof(p));
return f(fd, bufs, nbufs, off); return f(fd, bufs, nbufs, off);
} }