Now that AIOPool no longer keeps a freelist, it isn't really a "pool" anymore. Rename it to AIOCBInfo and make it const since it no longer needs to be modified. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
217 lines
5.5 KiB
C
217 lines
5.5 KiB
C
/*
|
|
* Linux native AIO support.
|
|
*
|
|
* Copyright (C) 2009 IBM, Corp.
|
|
* Copyright (C) 2009 Red Hat, Inc.
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2 or later.
|
|
* See the COPYING file in the top-level directory.
|
|
*/
|
|
#include "qemu-common.h"
|
|
#include "qemu-aio.h"
|
|
#include "qemu-queue.h"
|
|
#include "block/raw-aio.h"
|
|
#include "event_notifier.h"
|
|
|
|
#include <libaio.h>
|
|
|
|
/*
|
|
* Queue size (per-device).
|
|
*
|
|
* XXX: eventually we need to communicate this to the guest and/or make it
|
|
* tunable by the guest. If we get more outstanding requests at a time
|
|
* than this we will get EAGAIN from io_submit which is communicated to
|
|
* the guest as an I/O error.
|
|
*/
|
|
#define MAX_EVENTS 128
|
|
|
|
struct qemu_laiocb {
|
|
BlockDriverAIOCB common;
|
|
struct qemu_laio_state *ctx;
|
|
struct iocb iocb;
|
|
ssize_t ret;
|
|
size_t nbytes;
|
|
QEMUIOVector *qiov;
|
|
bool is_read;
|
|
QLIST_ENTRY(qemu_laiocb) node;
|
|
};
|
|
|
|
struct qemu_laio_state {
|
|
io_context_t ctx;
|
|
EventNotifier e;
|
|
int count;
|
|
};
|
|
|
|
static inline ssize_t io_event_ret(struct io_event *ev)
|
|
{
|
|
return (ssize_t)(((uint64_t)ev->res2 << 32) | ev->res);
|
|
}
|
|
|
|
/*
|
|
* Completes an AIO request (calls the callback and frees the ACB).
|
|
*/
|
|
static void qemu_laio_process_completion(struct qemu_laio_state *s,
|
|
struct qemu_laiocb *laiocb)
|
|
{
|
|
int ret;
|
|
|
|
s->count--;
|
|
|
|
ret = laiocb->ret;
|
|
if (ret != -ECANCELED) {
|
|
if (ret == laiocb->nbytes) {
|
|
ret = 0;
|
|
} else if (ret >= 0) {
|
|
/* Short reads mean EOF, pad with zeros. */
|
|
if (laiocb->is_read) {
|
|
qemu_iovec_memset(laiocb->qiov, ret, 0,
|
|
laiocb->qiov->size - ret);
|
|
} else {
|
|
ret = -EINVAL;
|
|
}
|
|
}
|
|
|
|
laiocb->common.cb(laiocb->common.opaque, ret);
|
|
}
|
|
|
|
qemu_aio_release(laiocb);
|
|
}
|
|
|
|
static void qemu_laio_completion_cb(EventNotifier *e)
|
|
{
|
|
struct qemu_laio_state *s = container_of(e, struct qemu_laio_state, e);
|
|
|
|
while (event_notifier_test_and_clear(&s->e)) {
|
|
struct io_event events[MAX_EVENTS];
|
|
struct timespec ts = { 0 };
|
|
int nevents, i;
|
|
|
|
do {
|
|
nevents = io_getevents(s->ctx, MAX_EVENTS, MAX_EVENTS, events, &ts);
|
|
} while (nevents == -EINTR);
|
|
|
|
for (i = 0; i < nevents; i++) {
|
|
struct iocb *iocb = events[i].obj;
|
|
struct qemu_laiocb *laiocb =
|
|
container_of(iocb, struct qemu_laiocb, iocb);
|
|
|
|
laiocb->ret = io_event_ret(&events[i]);
|
|
qemu_laio_process_completion(s, laiocb);
|
|
}
|
|
}
|
|
}
|
|
|
|
static int qemu_laio_flush_cb(EventNotifier *e)
|
|
{
|
|
struct qemu_laio_state *s = container_of(e, struct qemu_laio_state, e);
|
|
|
|
return (s->count > 0) ? 1 : 0;
|
|
}
|
|
|
|
static void laio_cancel(BlockDriverAIOCB *blockacb)
|
|
{
|
|
struct qemu_laiocb *laiocb = (struct qemu_laiocb *)blockacb;
|
|
struct io_event event;
|
|
int ret;
|
|
|
|
if (laiocb->ret != -EINPROGRESS)
|
|
return;
|
|
|
|
/*
|
|
* Note that as of Linux 2.6.31 neither the block device code nor any
|
|
* filesystem implements cancellation of AIO request.
|
|
* Thus the polling loop below is the normal code path.
|
|
*/
|
|
ret = io_cancel(laiocb->ctx->ctx, &laiocb->iocb, &event);
|
|
if (ret == 0) {
|
|
laiocb->ret = -ECANCELED;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* We have to wait for the iocb to finish.
|
|
*
|
|
* The only way to get the iocb status update is by polling the io context.
|
|
* We might be able to do this slightly more optimal by removing the
|
|
* O_NONBLOCK flag.
|
|
*/
|
|
while (laiocb->ret == -EINPROGRESS) {
|
|
qemu_laio_completion_cb(&laiocb->ctx->e);
|
|
}
|
|
}
|
|
|
|
static const AIOCBInfo laio_aiocb_info = {
|
|
.aiocb_size = sizeof(struct qemu_laiocb),
|
|
.cancel = laio_cancel,
|
|
};
|
|
|
|
BlockDriverAIOCB *laio_submit(BlockDriverState *bs, void *aio_ctx, int fd,
|
|
int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
|
|
BlockDriverCompletionFunc *cb, void *opaque, int type)
|
|
{
|
|
struct qemu_laio_state *s = aio_ctx;
|
|
struct qemu_laiocb *laiocb;
|
|
struct iocb *iocbs;
|
|
off_t offset = sector_num * 512;
|
|
|
|
laiocb = qemu_aio_get(&laio_aiocb_info, bs, cb, opaque);
|
|
laiocb->nbytes = nb_sectors * 512;
|
|
laiocb->ctx = s;
|
|
laiocb->ret = -EINPROGRESS;
|
|
laiocb->is_read = (type == QEMU_AIO_READ);
|
|
laiocb->qiov = qiov;
|
|
|
|
iocbs = &laiocb->iocb;
|
|
|
|
switch (type) {
|
|
case QEMU_AIO_WRITE:
|
|
io_prep_pwritev(iocbs, fd, qiov->iov, qiov->niov, offset);
|
|
break;
|
|
case QEMU_AIO_READ:
|
|
io_prep_preadv(iocbs, fd, qiov->iov, qiov->niov, offset);
|
|
break;
|
|
/* Currently Linux kernel does not support other operations */
|
|
default:
|
|
fprintf(stderr, "%s: invalid AIO request type 0x%x.\n",
|
|
__func__, type);
|
|
goto out_free_aiocb;
|
|
}
|
|
io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e));
|
|
s->count++;
|
|
|
|
if (io_submit(s->ctx, 1, &iocbs) < 0)
|
|
goto out_dec_count;
|
|
return &laiocb->common;
|
|
|
|
out_dec_count:
|
|
s->count--;
|
|
out_free_aiocb:
|
|
qemu_aio_release(laiocb);
|
|
return NULL;
|
|
}
|
|
|
|
void *laio_init(void)
|
|
{
|
|
struct qemu_laio_state *s;
|
|
|
|
s = g_malloc0(sizeof(*s));
|
|
if (event_notifier_init(&s->e, false) < 0) {
|
|
goto out_free_state;
|
|
}
|
|
|
|
if (io_setup(MAX_EVENTS, &s->ctx) != 0) {
|
|
goto out_close_efd;
|
|
}
|
|
|
|
qemu_aio_set_event_notifier(&s->e, qemu_laio_completion_cb,
|
|
qemu_laio_flush_cb);
|
|
|
|
return s;
|
|
|
|
out_close_efd:
|
|
event_notifier_cleanup(&s->e);
|
|
out_free_state:
|
|
g_free(s);
|
|
return NULL;
|
|
}
|