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| | #include <aio.h>
#include <errno.h>
#include "pthread_impl.h"
#include "libc.h"
/* Due to the requirement that aio_suspend be async-signal-safe, we cannot
* use any locks, wait queues, etc. that would make it more efficient. The
* only obviously-correct algorithm is to generate a wakeup every time any
* aio operation finishes and have aio_suspend re-evaluate the completion
* status of each aiocb it was waiting on. */
static volatile int seq;
void __aio_wake(void)
{
a_inc(&seq);
__wake(&seq, -1, 1);
}
int aio_suspend(const struct aiocb *const cbs[], int cnt, const struct timespec *ts)
{
int i, last, first=1, ret=0;
struct timespec at;
if (cnt<0) {
errno = EINVAL;
return -1;
}
for (;;) {
last = seq;
for (i=0; i<cnt; i++) {
if (cbs[i] && cbs[i]->__err != EINPROGRESS)
return 0;
}
if (first && ts) {
clock_gettime(CLOCK_MONOTONIC, &at);
at.tv_sec += ts->tv_sec;
if ((at.tv_nsec += ts->tv_nsec) >= 1000000000) {
at.tv_nsec -= 1000000000;
at.tv_sec++;
}
first = 0;
}
ret = __timedwait(&seq, last, CLOCK_MONOTONIC,
ts ? &at : 0, 0, 0, 1);
if (ret == ETIMEDOUT) ret = EAGAIN;
if (ret) {
errno = ret;
return -1;
}
}
}
LFS64(aio_suspend);
|