1 /*

     2  * QEMU aio implementation

     3  *

     4  * Copyright IBM, Corp. 2008

     5  *

     6  * Authors:

     7  *  Anthony Liguori   <aliguori@us.ibm.com>

     8  *

     9  * This work is licensed under the terms of the GNU GPL, version 2.  See

    10  * the COPYING file in the top-level directory.

    11  *

    12  */

    13 

    14 #ifndef QEMU_AIO_H

    15 #define QEMU_AIO_H

    16 

    17 #include "qemu-common.h"

    18 #include "qemu-char.h"

    19 

    20 /* Returns 1 if there are still outstanding AIO requests; 0 otherwise */

    21 typedef int (AioFlushHandler)(void *opaque);

    22 

    23 /* Flush any pending AIO operation. This function will block until all

    24  * outstanding AIO operations have been completed or cancelled. */

    25 void qemu_aio_flush(void);

    26 

    27 /* Wait for a single AIO completion to occur.  This function will until a

    28  * single AIO opeartion has completed.  It is intended to be used as a looping

    29  * primative when simulating synchronous IO based on asynchronous IO. */

    30 void qemu_aio_wait(void);

    31 

    32 /* Register a file descriptor and associated callbacks.  Behaves very similarly

    33  * to qemu_set_fd_handler2.  Unlike qemu_set_fd_handler2, these callbacks will

    34  * be invoked when using either qemu_aio_wait() or qemu_aio_flush().

    35  *

    36  * Code that invokes AIO completion functions should rely on this function

    37  * instead of qemu_set_fd_handler[2].

    38  */

    39 int qemu_aio_set_fd_handler(int fd,

    40                             IOHandler *io_read,

    41                             IOHandler *io_write,

    42                             AioFlushHandler *io_flush,

    43                             void *opaque);

    44 

    45 #endif