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/*
* QEMU aio implementation
*
* 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.
*
*/
#ifndef QEMU_AIO_H
#define QEMU_AIO_H
#include "qemu-common.h"
#include "qemu-char.h"
typedef struct BlockDriverAIOCB BlockDriverAIOCB;
typedef void BlockDriverCompletionFunc(void *opaque, int ret);
typedef struct AIOPool {
void (*cancel)(BlockDriverAIOCB *acb);
int aiocb_size;
BlockDriverAIOCB *free_aiocb;
} AIOPool;
struct BlockDriverAIOCB {
AIOPool *pool;
BlockDriverState *bs;
BlockDriverCompletionFunc *cb;
void *opaque;
BlockDriverAIOCB *next;
};
void *qemu_aio_get(AIOPool *pool, BlockDriverState *bs,
BlockDriverCompletionFunc *cb, void *opaque);
void qemu_aio_release(void *p);
/* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
typedef int (AioFlushHandler)(void *opaque);
/* Runs all currently allowed AIO callbacks of completed requests in the
* respective AIO backend. Returns 0 if no requests was handled, non-zero
* if at least one queued request was handled. */
typedef int (AioProcessQueue)(void *opaque);
/* Flush any pending AIO operation. This function will block until all
* outstanding AIO operations have been completed or cancelled. */
void qemu_aio_flush(void);
/* Wait for a single AIO completion to occur. This function will wait
* until a single AIO event has completed and it will ensure something
* has moved before returning. This can issue new pending aio as
* result of executing I/O completion or bh callbacks. */
void qemu_aio_wait(void);
/*
* Runs all currently allowed AIO callbacks of completed requests. Returns 0
* if no requests were handled, non-zero if at least one request was
* processed.
*/
int qemu_aio_process_queue(void);
/* Register a file descriptor and associated callbacks. Behaves very similarly
* to qemu_set_fd_handler2. Unlike qemu_set_fd_handler2, these callbacks will
* be invoked when using either qemu_aio_wait() or qemu_aio_flush().
*
* Code that invokes AIO completion functions should rely on this function
* instead of qemu_set_fd_handler[2].
*/
int qemu_aio_set_fd_handler(int fd,
IOHandler *io_read,
IOHandler *io_write,
AioFlushHandler *io_flush,
AioProcessQueue *io_process_queue,
void *opaque);
#endif
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