9ef91a6771
Currently the raw-posix.c code contains a lot of knowledge about the asynchronous I/O scheme that is mostly implemented in posix-aio-compat.c. All this code does not really belong here and is getting a bit in the way of implementing native AIO on Linux. So instead move all the guts of the AIO implementation into posix-aio-compat.c (which might need a better name, btw). There's now a very small interface between the AIO providers and raw-posix.c: - an init routine is called from raw_open_common to return an AIO context for this drive. An AIO implementation may either re-use one context for all drives, or use a different one for each as the Linux native AIO support will do. - an submit routine is called from the aio_reav/writev methods to submit an AIO request There are no indirect calls involved in this interface as we need to decide which one to call manually. We will only call the Linux AIO native init function if we were requested to by vl.c, and we will only call the native submit function if we are asked to and the request is properly aligned. That's also the reason why the alignment check actually does the inverse move and now goes into raw-posix.c. The old posix-aio-compat.h headers is removed now that most of it's content is private to posix-aio-compat.c, and instead we add a new block/raw-posix-aio.h headers is created containing only the tiny interface between raw-posix.c and the AIO implementation. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
37 lines
1 KiB
C
37 lines
1 KiB
C
/*
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* QEMU Posix block I/O backend AIO support
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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_RAW_POSIX_AIO_H
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#define QEMU_RAW_POSIX_AIO_H
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/* AIO request types */
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#define QEMU_AIO_READ 0x0001
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#define QEMU_AIO_WRITE 0x0002
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#define QEMU_AIO_IOCTL 0x0004
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#define QEMU_AIO_TYPE_MASK \
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(QEMU_AIO_READ|QEMU_AIO_WRITE|QEMU_AIO_IOCTL)
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/* AIO flags */
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#define QEMU_AIO_MISALIGNED 0x1000
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/* posix-aio-compat.c - thread pool based implementation */
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void *paio_init(void);
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BlockDriverAIOCB *paio_submit(BlockDriverState *bs, void *aio_ctx, int fd,
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int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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BlockDriverCompletionFunc *cb, void *opaque, int type);
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BlockDriverAIOCB *paio_ioctl(BlockDriverState *bs, int fd,
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unsigned long int req, void *buf,
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BlockDriverCompletionFunc *cb, void *opaque);
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#endif /* QEMU_RAW_POSIX_AIO_H */
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