blob: b49b5de7f49e975a3609c9686e6f30403b56d222 [file] [log] [blame]
* Linux AIO request queue
* Copyright 2012 IBM, Corp.
* Copyright 2012 Red Hat, Inc. and/or its affiliates
* Authors:
* Stefan Hajnoczi <>
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
#ifndef IOQ_H
#define IOQ_H
#include <libaio.h>
#include "qemu/event_notifier.h"
typedef struct {
int fd; /* file descriptor */
unsigned int max_reqs; /* max length of freelist and queue */
io_context_t io_ctx; /* Linux AIO context */
EventNotifier io_notifier; /* Linux AIO eventfd */
/* Requests can complete in any order so a free list is necessary to manage
* available iocbs.
struct iocb **freelist; /* free iocbs */
unsigned int freelist_idx;
/* Multiple requests are queued up before submitting them all in one go */
struct iocb **queue; /* queued iocbs */
unsigned int queue_idx;
} IOQueue;
void ioq_init(IOQueue *ioq, int fd, unsigned int max_reqs);
void ioq_cleanup(IOQueue *ioq);
EventNotifier *ioq_get_notifier(IOQueue *ioq);
struct iocb *ioq_get_iocb(IOQueue *ioq);
void ioq_put_iocb(IOQueue *ioq, struct iocb *iocb);
struct iocb *ioq_rdwr(IOQueue *ioq, bool read, struct iovec *iov,
unsigned int count, long long offset);
int ioq_submit(IOQueue *ioq);
static inline unsigned int ioq_num_queued(IOQueue *ioq)
return ioq->queue_idx;
typedef void IOQueueCompletion(struct iocb *iocb, ssize_t ret, void *opaque);
int ioq_run_completion(IOQueue *ioq, IOQueueCompletion *completion,
void *opaque);
#endif /* IOQ_H */