Merge remote-tracking branch 'stefanha/trivial-patches' into staging
[qemu.git] / qemu-aio.h
blobbfdd35f02cfa6e61c09507f28c763af39022b498
1 /*
2 * QEMU aio implementation
4 * Copyright IBM, Corp. 2008
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
14 #ifndef QEMU_AIO_H
15 #define QEMU_AIO_H
17 #include "qemu-common.h"
18 #include "qemu-char.h"
20 typedef struct BlockDriverAIOCB BlockDriverAIOCB;
21 typedef void BlockDriverCompletionFunc(void *opaque, int ret);
23 typedef struct AIOPool {
24 void (*cancel)(BlockDriverAIOCB *acb);
25 int aiocb_size;
26 BlockDriverAIOCB *free_aiocb;
27 } AIOPool;
29 struct BlockDriverAIOCB {
30 AIOPool *pool;
31 BlockDriverState *bs;
32 BlockDriverCompletionFunc *cb;
33 void *opaque;
34 BlockDriverAIOCB *next;
37 void *qemu_aio_get(AIOPool *pool, BlockDriverState *bs,
38 BlockDriverCompletionFunc *cb, void *opaque);
39 void qemu_aio_release(void *p);
41 /* Returns 1 if there are still outstanding AIO requests; 0 otherwise */
42 typedef int (AioFlushHandler)(void *opaque);
44 /* Flush any pending AIO operation. This function will block until all
45 * outstanding AIO operations have been completed or cancelled. */
46 void qemu_aio_flush(void);
48 /* Wait for a single AIO completion to occur. This function will wait
49 * until a single AIO event has completed and it will ensure something
50 * has moved before returning. This can issue new pending aio as
51 * result of executing I/O completion or bh callbacks.
53 * Return whether there is still any pending AIO operation. */
54 bool qemu_aio_wait(void);
56 /* Register a file descriptor and associated callbacks. Behaves very similarly
57 * to qemu_set_fd_handler2. Unlike qemu_set_fd_handler2, these callbacks will
58 * be invoked when using either qemu_aio_wait() or qemu_aio_flush().
60 * Code that invokes AIO completion functions should rely on this function
61 * instead of qemu_set_fd_handler[2].
63 int qemu_aio_set_fd_handler(int fd,
64 IOHandler *io_read,
65 IOHandler *io_write,
66 AioFlushHandler *io_flush,
67 void *opaque);
69 #endif