f141eafe28
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
69 lines
1.6 KiB
C
69 lines
1.6 KiB
C
/*
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* QEMU posix-aio emulation
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*
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* Copyright IBM, Corp. 2008
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*
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* Authors:
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* Anthony Liguori <aliguori@us.ibm.com>
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*
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* This work is licensed under the terms of the GNU GPL, version 2. See
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* the COPYING file in the top-level directory.
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*
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*/
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#ifndef QEMU_POSIX_AIO_COMPAT_H
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#define QEMU_POSIX_AIO_COMPAT_H
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#include <sys/types.h>
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#include <unistd.h>
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#include <signal.h>
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#include "sys-queue.h"
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#define QEMU_PAIO_CANCELED 0x01
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#define QEMU_PAIO_NOTCANCELED 0x02
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#define QEMU_PAIO_ALLDONE 0x03
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struct qemu_paiocb
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{
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int aio_fildes;
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union {
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struct iovec *aio_iov;
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void *aio_ioctl_buf;
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};
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int aio_niov;
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size_t aio_nbytes;
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#define aio_ioctl_cmd aio_nbytes /* for QEMU_PAIO_IOCTL */
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int ev_signo;
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off_t aio_offset;
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unsigned aio_flags;
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/* 512 byte alignment required for buffer, offset and length */
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#define QEMU_AIO_SECTOR_ALIGNED 0x01
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/* private */
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TAILQ_ENTRY(qemu_paiocb) node;
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int aio_type;
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#define QEMU_PAIO_READ 0x01
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#define QEMU_PAIO_WRITE 0x02
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#define QEMU_PAIO_IOCTL 0x03
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ssize_t ret;
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int active;
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};
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struct qemu_paioinit
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{
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unsigned int aio_threads;
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unsigned int aio_num;
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unsigned int aio_idle_time;
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};
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int qemu_paio_init(struct qemu_paioinit *aioinit);
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int qemu_paio_read(struct qemu_paiocb *aiocb);
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int qemu_paio_write(struct qemu_paiocb *aiocb);
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int qemu_paio_ioctl(struct qemu_paiocb *aiocb);
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int qemu_paio_error(struct qemu_paiocb *aiocb);
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ssize_t qemu_paio_return(struct qemu_paiocb *aiocb);
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int qemu_paio_cancel(int fd, struct qemu_paiocb *aiocb);
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#endif
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