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nptl: Extend __futex_abstimed_wait_cancelable64 comment

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And add a small optimization to avoid setting the operation for the
32-bit time fallback operation.

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
This commit is contained in:
Adhemerval Zanella 2020-11-20 10:58:51 -03:00
parent 9e92278ffa
commit e77221a523
2 changed files with 13 additions and 9 deletions
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8
sysdeps/nptl/futex-internal.c
View File

@ -25,7 +25,7 @@
#ifndef __ASSUME_TIME64_SYSCALLS
static int
__futex_abstimed_wait_cancelable32 (unsigned int* futex_word,
unsigned int expected, clockid_t clockid,
unsigned int expected, int op,
const struct __timespec64* abstime,
int private)
{
@ -39,10 +39,6 @@ __futex_abstimed_wait_cancelable32 (unsigned int* futex_word,
pts32 = &ts32;
}
unsigned int clockbit = (clockid == CLOCK_REALTIME)
? FUTEX_CLOCK_REALTIME : 0;
int op = __lll_private_flag (FUTEX_WAIT_BITSET | clockbit, private);
return INTERNAL_SYSCALL_CANCEL (futex, futex_word, op, expected,
pts32, NULL /* Unused. */,
FUTEX_BITSET_MATCH_ANY);
@ -119,7 +115,7 @@ __futex_abstimed_wait_cancelable64 (unsigned int* futex_word,
#ifndef __ASSUME_TIME64_SYSCALLS
if (err == -ENOSYS)
err = __futex_abstimed_wait_cancelable32 (futex_word, expected,
clockid, abstime, private);
op, abstime, private);
#endif
switch (err)

14
sysdeps/nptl/futex-internal.h
View File

@ -390,9 +390,17 @@ futex_unlock_pi (unsigned int *futex_word, int private)
}
}
/* The futex_abstimed_wait_cancelable64 has been moved to a separate file
to avoid problems with exhausting available registers on some architectures
- e.g. on m68k architecture. */
/* Like futex_wait, but will eventually time out (i.e., stop being blocked)
after the duration of time provided (i.e., ABSTIME) has passed using the
clock specified by CLOCKID (currently only CLOCK_REALTIME and
CLOCK_MONOTONIC, the ones support by lll_futex_supported_clockid). ABSTIME
can also equal NULL, in which case this function behaves equivalent to
futex_wait.
Returns the same values as futex_wait under those same conditions;
additionally, returns ETIMEDOUT if the timeout expired.
The call acts as a cancellation entrypoint. */
int
__futex_abstimed_wait_cancelable64 (unsigned int* futex_word,
unsigned int expected, clockid_t clockid,