qemu/posix-aio-compat.h
aliguori f141eafe28 push down vector linearization to posix-aio-compat.c (Christoph Hellwig)
Make all AIO requests vectored and defer linearization until the actual
I/O thread.  This prepares for using native preadv/pwritev.

Also enables asynchronous direct I/O by handling that case in the I/O thread.

Qcow and qcow2 propably want to be adopted to directly deal with multi-segment
requests, but that can be implemented later.


Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@7020 c046a42c-6fe2-441c-8c8c-71466251a162
2009-04-07 18:43:24 +00:00

69 lines
1.6 KiB
C

/*
* QEMU posix-aio emulation
*
* 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_POSIX_AIO_COMPAT_H
#define QEMU_POSIX_AIO_COMPAT_H
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>
#include "sys-queue.h"
#define QEMU_PAIO_CANCELED 0x01
#define QEMU_PAIO_NOTCANCELED 0x02
#define QEMU_PAIO_ALLDONE 0x03
struct qemu_paiocb
{
int aio_fildes;
union {
struct iovec *aio_iov;
void *aio_ioctl_buf;
};
int aio_niov;
size_t aio_nbytes;
#define aio_ioctl_cmd aio_nbytes /* for QEMU_PAIO_IOCTL */
int ev_signo;
off_t aio_offset;
unsigned aio_flags;
/* 512 byte alignment required for buffer, offset and length */
#define QEMU_AIO_SECTOR_ALIGNED 0x01
/* private */
TAILQ_ENTRY(qemu_paiocb) node;
int aio_type;
#define QEMU_PAIO_READ 0x01
#define QEMU_PAIO_WRITE 0x02
#define QEMU_PAIO_IOCTL 0x03
ssize_t ret;
int active;
};
struct qemu_paioinit
{
unsigned int aio_threads;
unsigned int aio_num;
unsigned int aio_idle_time;
};
int qemu_paio_init(struct qemu_paioinit *aioinit);
int qemu_paio_read(struct qemu_paiocb *aiocb);
int qemu_paio_write(struct qemu_paiocb *aiocb);
int qemu_paio_ioctl(struct qemu_paiocb *aiocb);
int qemu_paio_error(struct qemu_paiocb *aiocb);
ssize_t qemu_paio_return(struct qemu_paiocb *aiocb);
int qemu_paio_cancel(int fd, struct qemu_paiocb *aiocb);
#endif