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nptl: Use FUTEX_LOCK_PI2 when available

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This patch uses the new futex PI operation provided by Linux v5.14
when it is required.

The futex_lock_pi64() is moved to futex-internal.c (since it used on
two different places and its code size might be large depending of the
kernel configuration) and clockid is added as an argument.

Co-authored-by: Kurt Kanzenbach <kurt@linutronix.de>
This commit is contained in:
Adhemerval Zanella
2021-06-25 10:11:00 +02:00
parent dd5adb515c
commit 8352b6df37
5 changed files with 72 additions and 56 deletions
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63
nptl/futex-internal.c
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@@ -140,3 +140,66 @@ __futex_abstimed_wait_cancelable64 (unsigned int* futex_word,
abstime, private, true);
}
libc_hidden_def (__futex_abstimed_wait_cancelable64)
int
__futex_lock_pi64 (int *futex_word, clockid_t clockid,
const struct __timespec64 *abstime, int private)
{
int err;
unsigned int clockbit = clockid == CLOCK_REALTIME
? FUTEX_CLOCK_REALTIME : 0;
int op_pi2 = __lll_private_flag (FUTEX_LOCK_PI2 | clockbit, private);
#if __ASSUME_FUTEX_LOCK_PI2
/* Assume __ASSUME_TIME64_SYSCALLS since FUTEX_LOCK_PI2 was added later. */
err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi2, 0, abstime);
#else
/* FUTEX_LOCK_PI does not support clock selection, so for CLOCK_MONOTONIC
the only option is to use FUTEX_LOCK_PI2. */
int op_pi1 = __lll_private_flag (FUTEX_LOCK_PI, private);
int op_pi = abstime != NULL && clockid != CLOCK_REALTIME ? op_pi2 : op_pi1;
# ifdef __ASSUME_TIME64_SYSCALLS
err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi, 0, abstime);
# else
bool need_time64 = abstime != NULL && !in_time_t_range (abstime->tv_sec);
if (need_time64)
err = INTERNAL_SYSCALL_CALL (futex_time64, futex_word, op_pi, 0, abstime);
else
{
struct timespec ts32, *pts32 = NULL;
if (abstime != NULL)
{
ts32 = valid_timespec64_to_timespec (*abstime);
pts32 = &ts32;
}
err = INTERNAL_SYSCALL_CALL (futex, futex_word, op_pi, 0, pts32);
}
# endif /* __ASSUME_TIME64_SYSCALLS */
/* FUTEX_LOCK_PI2 is not available on this kernel. */
if (err == -ENOSYS)
err = -EINVAL;
#endif /* __ASSUME_FUTEX_LOCK_PI2 */
switch (err)
{
case 0:
case -EAGAIN:
case -EINTR:
case -ETIMEDOUT:
case -ESRCH:
case -EDEADLK:
case -EINVAL: /* This indicates either state corruption or that the kernel
found a waiter on futex address which is waiting via
FUTEX_WAIT or FUTEX_WAIT_BITSET. This is reported on
some futex_lock_pi usage (pthread_mutex_timedlock for
instance). */
return -err;
case -EFAULT: /* Must have been caused by a glibc or application bug. */
case -ENOSYS: /* Must have been caused by a glibc bug. */
/* No other errors are documented at this time. */
default:
futex_fatal_error ();
}
}