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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 <time.h>
#include <string.h>
#include <stdlib.h>
#include <stdio.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 pthread_attr_t attr;
static int max_threads = 64;
static int cur_threads = 0;
static int idle_threads = 0;
static TAILQ_HEAD(, qemu_paiocb) request_list;
static void die2(int err, const char *what)
{
fprintf(stderr, "%s failed: %s\n", what, strerror(err));
abort();
}
static void die(const char *what)
{
die2(errno, what);
}
static void mutex_lock(pthread_mutex_t *mutex)
{
int ret = pthread_mutex_lock(mutex);
if (ret) die2(ret, "pthread_mutex_lock");
}
static void mutex_unlock(pthread_mutex_t *mutex)
{
int ret = pthread_mutex_unlock(mutex);
if (ret) die2(ret, "pthread_mutex_unlock");
}
static int cond_timedwait(pthread_cond_t *cond, pthread_mutex_t *mutex,
struct timespec *ts)
{
int ret = pthread_cond_timedwait(cond, mutex, ts);
if (ret && ret != ETIMEDOUT) die2(ret, "pthread_cond_timedwait");
return ret;
}
static void cond_signal(pthread_cond_t *cond)
{
int ret = pthread_cond_signal(cond);
if (ret) die2(ret, "pthread_cond_signal");
}
static void thread_create(pthread_t *thread, pthread_attr_t *attr,
void *(*start_routine)(void*), void *arg)
{
int ret = pthread_create(thread, attr, start_routine, arg);
if (ret) die2(ret, "pthread_create");
}
static void *aio_thread(void *unused)
{
pid_t pid;
sigset_t set;
pid = getpid();
/* block all signals */
if (sigfillset(&set)) die("sigfillset");
if (sigprocmask(SIG_BLOCK, &set, NULL)) die("sigprocmask");
while (1) {
struct qemu_paiocb *aiocb;
size_t offset;
int ret = 0;
qemu_timeval tv;
struct timespec ts;
qemu_gettimeofday(&tv);
ts.tv_sec = tv.tv_sec + 10;
ts.tv_nsec = 0;
mutex_lock(&lock);
while (TAILQ_EMPTY(&request_list) &&
!(ret == ETIMEDOUT)) {
ret = cond_timedwait(&cond, &lock, &ts);
}
if (TAILQ_EMPTY(&request_list))
break;
aiocb = TAILQ_FIRST(&request_list);
TAILQ_REMOVE(&request_list, aiocb, node);
offset = 0;
aiocb->active = 1;
idle_threads--;
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) {
offset = -errno;
break;
} else if (len == 0)
break;
offset += len;
}
mutex_lock(&lock);
aiocb->ret = offset;
idle_threads++;
mutex_unlock(&lock);
if (kill(pid, aiocb->ev_signo)) die("kill failed");
}
idle_threads--;
cur_threads--;
mutex_unlock(&lock);
return NULL;
}
static void spawn_thread(void)
{
cur_threads++;
idle_threads++;
thread_create(&thread_id, &attr, aio_thread, NULL);
}
int qemu_paio_init(struct qemu_paioinit *aioinit)
{
int ret;
ret = pthread_attr_init(&attr);
if (ret) die2(ret, "pthread_attr_init");
ret = pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
if (ret) die2(ret, "pthread_attr_setdetachstate");
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;
mutex_lock(&lock);
if (idle_threads == 0 && cur_threads < max_threads)
spawn_thread();
TAILQ_INSERT_TAIL(&request_list, aiocb, node);
mutex_unlock(&lock);
cond_signal(&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;
mutex_lock(&lock);
ret = aiocb->ret;
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;
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;
mutex_unlock(&lock);
return ret;
}
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