1 /* 2 * QEMU aio implementation 3 * 4 * Copyright IBM, Corp. 2008 5 * 6 * Authors: 7 * Anthony Liguori <aliguori (at) 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 /* Runs all currently allowed AIO callbacks of completed requests in the 24 * respective AIO backend. Returns 0 if no requests was handled, non-zero 25 * if at least one queued request was handled. */ 26 typedef int (AioProcessQueue)(void *opaque); 27 28 /* Flush any pending AIO operation. This function will block until all 29 * outstanding AIO operations have been completed or cancelled. */ 30 void qemu_aio_flush(void); 31 32 /* Wait for a single AIO completion to occur. This function will wait 33 * until a single AIO event has completed and it will ensure something 34 * has moved before returning. This can issue new pending aio as 35 * result of executing I/O completion or bh callbacks. */ 36 void qemu_aio_wait(void); 37 38 /* 39 * Runs all currently allowed AIO callbacks of completed requests. Returns 0 40 * if no requests were handled, non-zero if at least one request was 41 * processed. 42 */ 43 int qemu_aio_process_queue(void); 44 45 /* Register a file descriptor and associated callbacks. Behaves very similarly 46 * to qemu_set_fd_handler2. Unlike qemu_set_fd_handler2, these callbacks will 47 * be invoked when using either qemu_aio_wait() or qemu_aio_flush(). 48 * 49 * Code that invokes AIO completion functions should rely on this function 50 * instead of qemu_set_fd_handler[2]. 51 */ 52 int qemu_aio_set_fd_handler(int fd, 53 IOHandler *io_read, 54 IOHandler *io_write, 55 AioFlushHandler *io_flush, 56 AioProcessQueue *io_process_queue, 57 void *opaque); 58 59 #endif 60
