diff options
Diffstat (limited to 'rt/lio_listio.c')
-rw-r--r-- | rt/lio_listio.c | 112 |
1 files changed, 98 insertions, 14 deletions
diff --git a/rt/lio_listio.c b/rt/lio_listio.c index 73df5c2..b389c6a 100644 --- a/rt/lio_listio.c +++ b/rt/lio_listio.c @@ -20,11 +20,20 @@ #include <aio.h> #include <errno.h> -#include <semaphore.h> +#include <stdlib.h> #include "aio_misc.h" +/* We need this special structure to handle asynchronous I/O. */ +struct async_waitlist + { + int counter; + struct sigevent sigev; + struct waitlist list[0]; + }; + + int lio_listio (mode, list, nent, sig) int mode; @@ -32,8 +41,9 @@ lio_listio (mode, list, nent, sig) int nent; struct sigevent *sig; { + struct requestlist *requests[nent]; int cnt; - int total = 0; + volatile int total = 0; int result = 0; /* Check arguments. */ @@ -43,26 +53,100 @@ lio_listio (mode, list, nent, sig) return -1; } - /* Request the semaphore. */ - sem_wait (&__aio_requests_sema); + /* Request the mutex. */ + pthread_mutex_lock (&__aio_requests_mutex); /* Now we can enqueue all requests. Since we already acquired the - semaphore the enqueue function need not do this. */ + mutex the enqueue function need not do this. */ for (cnt = 0; cnt < nent; ++cnt) if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP) - if (__aio_enqueue_request ((aiocb_union *) list[cnt], - list[cnt]->aio_lio_opcode, 0) >= 0) - /* Successfully enqueued. */ - ++total; + { + requests[cnt] = __aio_enqueue_request ((aiocb_union *) list[cnt], + list[cnt]->aio_lio_opcode); + + if (requests[cnt] != NULL) + /* Successfully enqueued. */ + ++total; + else + /* Signal that we've seen an error. `errno' and the error code + of the aiocb will tell more. */ + result = -1; + } + + if (total == 0) + { + /* We don't have anything to do except signalling if we work + asynchronously. */ + if (mode == LIO_NOWAIT) + __aio_notify_only (sig); + } + else if (mode == LIO_WAIT) + { + pthread_cond_t cond; + struct waitlist waitlist[nent]; + int oldstate; + + total = 0; + for (cnt = 0; cnt < nent; ++cnt) + if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP + && requests[cnt] != NULL) + { + waitlist[cnt].cond = &cond; + waitlist[cnt].next = requests[cnt]->waiting; + waitlist[cnt].counterp = NULL; + waitlist[cnt].sigevp = NULL; + requests[cnt]->waiting = &waitlist[cnt]; + ++total; + } + + /* Since `pthread_cond_wait'/`pthread_cond_timedwait' are cancelation + points we must be careful. We added entries to the waiting lists + which we must remove. So defer cancelation for now. */ + pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &oldstate); + + while (total > 0) + if (pthread_cond_wait (&cond, &__aio_requests_mutex) == 0) + --total; + + /* Now it's time to restore the cancelation state. */ + pthread_setcancelstate (oldstate, NULL); + } + else + { + struct async_waitlist *waitlist; + + waitlist = (struct async_waitlist *) + malloc (sizeof (struct async_waitlist) + + (nent * sizeof (struct waitlist))); + + if (waitlist == NULL) + { + __set_errno (EAGAIN); + result = -1; + } else - /* Signal that we've seen an error. `errno' and the error code - of the aiocb will tell more. */ - result = -1; + { + total = 0; + for (cnt = 0; cnt < nent; ++cnt) + if (list[cnt] != NULL && list[cnt]->aio_lio_opcode != LIO_NOP + && requests[cnt] != NULL) + { + waitlist->list[cnt].cond = NULL; + waitlist->list[cnt].next = requests[cnt]->waiting; + waitlist->list[cnt].counterp = &waitlist->counter; + waitlist->list[cnt].sigevp = &waitlist->sigev; + requests[cnt]->waiting = &waitlist->list[cnt]; + ++total; + } + waitlist->counter = total; + waitlist->sigev = *sig; + } + } - /* Release the semaphore. */ - sem_post (&__aio_requests_sema); + /* Release the mutex. */ + pthread_mutex_unlock (&__aio_requests_mutex); return result; } |