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/*
* QEMU posix-aio emulation
*
* Copyright IBM, Corp. 2008
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
*/
#include <pthread.h>
#include <unistd.h>
#include <errno.h>
#include <sys/time.h>
#include "osdep.h"
#include "posix-aio-compat.h"
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
static pthread_t thread_id;
static int max_threads = 64;
static int cur_threads = 0;
static int idle_threads = 0;
static TAILQ_HEAD(, qemu_paiocb) request_list;
static void *aio_thread(void *unused)
{
sigset_t set;
/* block all signals */
sigfillset(&set);
sigprocmask(SIG_BLOCK, &set, NULL);
while (1) {
struct qemu_paiocb *aiocb;
size_t offset;
int ret = 0;
pthread_mutex_lock(&lock);
while (TAILQ_EMPTY(&request_list) &&
!(ret == ETIMEDOUT)) {
struct timespec ts = { 0 };
qemu_timeval tv;
qemu_gettimeofday(&tv);
ts.tv_sec = tv.tv_sec + 10;
ret = pthread_cond_timedwait(&cond, &lock, &ts);
}
if (ret == ETIMEDOUT)
break;
aiocb = TAILQ_FIRST(&request_list);
TAILQ_REMOVE(&request_list, aiocb, node);
offset = 0;
aiocb->active = 1;
idle_threads--;
pthread_mutex_unlock(&lock);
while (offset < aiocb->aio_nbytes) {
ssize_t len;
if (aiocb->is_write)
len = pwrite(aiocb->aio_fildes,
(const char *)aiocb->aio_buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
else
len = pread(aiocb->aio_fildes,
(char *)aiocb->aio_buf + offset,
aiocb->aio_nbytes - offset,
aiocb->aio_offset + offset);
if (len == -1 && errno == EINTR)
continue;
else if (len == -1) {
pthread_mutex_lock(&lock);
aiocb->ret = -errno;
pthread_mutex_unlock(&lock);
break;
} else if (len == 0)
break;
offset += len;
pthread_mutex_lock(&lock);
aiocb->ret = offset;
pthread_mutex_unlock(&lock);
}
pthread_mutex_lock(&lock);
idle_threads++;
pthread_mutex_unlock(&lock);
sigqueue(getpid(),
aiocb->aio_sigevent.sigev_signo,
aiocb->aio_sigevent.sigev_value);
}
idle_threads--;
cur_threads--;
pthread_mutex_unlock(&lock);
return NULL;
}
static int spawn_thread(void)
{
pthread_attr_t attr;
int ret;
cur_threads++;
idle_threads++;
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
ret = pthread_create(&thread_id, &attr, aio_thread, NULL);
pthread_attr_destroy(&attr);
return ret;
}
int qemu_paio_init(struct qemu_paioinit *aioinit)
{
TAILQ_INIT(&request_list);
return 0;
}
static int qemu_paio_submit(struct qemu_paiocb *aiocb, int is_write)
{
aiocb->is_write = is_write;
aiocb->ret = -EINPROGRESS;
aiocb->active = 0;
pthread_mutex_lock(&lock);
if (idle_threads == 0 && cur_threads < max_threads)
spawn_thread();
TAILQ_INSERT_TAIL(&request_list, aiocb, node);
pthread_mutex_unlock(&lock);
pthread_cond_broadcast(&cond);
return 0;
}
int qemu_paio_read(struct qemu_paiocb *aiocb)
{
return qemu_paio_submit(aiocb, 0);
}
int qemu_paio_write(struct qemu_paiocb *aiocb)
{
return qemu_paio_submit(aiocb, 1);
}
ssize_t qemu_paio_return(struct qemu_paiocb *aiocb)
{
ssize_t ret;
pthread_mutex_lock(&lock);
ret = aiocb->ret;
pthread_mutex_unlock(&lock);
return ret;
}
int qemu_paio_error(struct qemu_paiocb *aiocb)
{
ssize_t ret = qemu_paio_return(aiocb);
if (ret < 0)
ret = -ret;
else
ret = 0;
return ret;
}
int qemu_paio_cancel(int fd, struct qemu_paiocb *aiocb)
{
int ret;
pthread_mutex_lock(&lock);
if (!aiocb->active) {
TAILQ_REMOVE(&request_list, aiocb, node);
aiocb->ret = -ECANCELED;
ret = QEMU_PAIO_CANCELED;
} else if (aiocb->ret == -EINPROGRESS)
ret = QEMU_PAIO_NOTCANCELED;
else
ret = QEMU_PAIO_ALLDONE;
pthread_mutex_unlock(&lock);
return ret;
}
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