raw-posix: Switch to bdrv_co_* interfaces
In order to use the modern byte-based .bdrv_co_preadv/pwritev() interface, this patch switches raw-posix to coroutine-based interfaces as a first step. In terms of semantics and performance, it doesn't make a difference with the existing code whether we go from a coroutine to a callback-based interface already in block/io.c or only in linux-aio.c As there have been concerns in the past that this change may be a step in the wrong direction with respect to a possible AIO fast path, the old callback-based interface for linux-aio is left around and can be reactivated when a fast path (e.g. directly from virtio-blk dataplane, bypassing the whole block layer) is implemented. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Kevin Wolf
parent
9896c8765f
commit
2174f12bde
@ -11,8 +11,10 @@
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#include "qemu-common.h"
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#include "block/aio.h"
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#include "qemu/queue.h"
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#include "block/block.h"
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#include "block/raw-aio.h"
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#include "qemu/event_notifier.h"
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#include "qemu/coroutine.h"
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#include <libaio.h>
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@ -30,6 +32,7 @@
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struct qemu_laiocb {
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BlockAIOCB common;
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Coroutine *co;
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LinuxAioState *ctx;
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struct iocb iocb;
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ssize_t ret;
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@ -88,9 +91,14 @@ static void qemu_laio_process_completion(struct qemu_laiocb *laiocb)
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}
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}
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}
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laiocb->common.cb(laiocb->common.opaque, ret);
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laiocb->ret = ret;
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if (laiocb->co) {
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qemu_coroutine_enter(laiocb->co, NULL);
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} else {
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laiocb->common.cb(laiocb->common.opaque, ret);
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qemu_aio_unref(laiocb);
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}
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}
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/* The completion BH fetches completed I/O requests and invokes their
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@ -230,22 +238,12 @@ void laio_io_unplug(BlockDriverState *bs, LinuxAioState *s)
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}
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}
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BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
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int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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BlockCompletionFunc *cb, void *opaque, int type)
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static int laio_do_submit(int fd, struct qemu_laiocb *laiocb, off_t offset,
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int type)
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{
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struct qemu_laiocb *laiocb;
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struct iocb *iocbs;
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off_t offset = sector_num * 512;
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laiocb = qemu_aio_get(&laio_aiocb_info, bs, cb, opaque);
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laiocb->nbytes = nb_sectors * 512;
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laiocb->ctx = s;
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laiocb->ret = -EINPROGRESS;
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laiocb->is_read = (type == QEMU_AIO_READ);
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laiocb->qiov = qiov;
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iocbs = &laiocb->iocb;
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LinuxAioState *s = laiocb->ctx;
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struct iocb *iocbs = &laiocb->iocb;
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QEMUIOVector *qiov = laiocb->qiov;
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switch (type) {
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case QEMU_AIO_WRITE:
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@ -258,7 +256,7 @@ BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
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default:
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fprintf(stderr, "%s: invalid AIO request type 0x%x.\n",
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__func__, type);
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goto out_free_aiocb;
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return -EIO;
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}
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io_set_eventfd(&laiocb->iocb, event_notifier_get_fd(&s->e));
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@ -268,11 +266,56 @@ BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
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(!s->io_q.plugged || s->io_q.n >= MAX_QUEUED_IO)) {
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ioq_submit(s);
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}
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return &laiocb->common;
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out_free_aiocb:
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return 0;
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}
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int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
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int64_t sector_num, QEMUIOVector *qiov,
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int nb_sectors, int type)
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{
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off_t offset = sector_num * BDRV_SECTOR_SIZE;
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int ret;
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struct qemu_laiocb laiocb = {
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.co = qemu_coroutine_self(),
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.nbytes = nb_sectors * BDRV_SECTOR_SIZE,
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.ctx = s,
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.is_read = (type == QEMU_AIO_READ),
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.qiov = qiov,
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};
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ret = laio_do_submit(fd, &laiocb, offset, type);
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if (ret < 0) {
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return ret;
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}
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qemu_coroutine_yield();
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return laiocb.ret;
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}
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BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
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int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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BlockCompletionFunc *cb, void *opaque, int type)
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{
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struct qemu_laiocb *laiocb;
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off_t offset = sector_num * BDRV_SECTOR_SIZE;
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int ret;
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laiocb = qemu_aio_get(&laio_aiocb_info, bs, cb, opaque);
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laiocb->nbytes = nb_sectors * BDRV_SECTOR_SIZE;
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laiocb->ctx = s;
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laiocb->ret = -EINPROGRESS;
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laiocb->is_read = (type == QEMU_AIO_READ);
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laiocb->qiov = qiov;
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ret = laio_do_submit(fd, laiocb, offset, type);
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if (ret < 0) {
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qemu_aio_unref(laiocb);
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return NULL;
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}
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return &laiocb->common;
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}
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void laio_detach_aio_context(LinuxAioState *s, AioContext *old_context)
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@ -15,6 +15,7 @@
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#ifndef QEMU_RAW_AIO_H
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#define QEMU_RAW_AIO_H
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#include "qemu/coroutine.h"
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#include "qemu/iov.h"
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/* AIO request types */
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@ -38,6 +39,9 @@
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typedef struct LinuxAioState LinuxAioState;
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LinuxAioState *laio_init(void);
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void laio_cleanup(LinuxAioState *s);
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int coroutine_fn laio_co_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
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int64_t sector_num, QEMUIOVector *qiov,
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int nb_sectors, int type);
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BlockAIOCB *laio_submit(BlockDriverState *bs, LinuxAioState *s, int fd,
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int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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BlockCompletionFunc *cb, void *opaque, int type);
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@ -1325,14 +1325,13 @@ static BlockAIOCB *paio_submit(BlockDriverState *bs, int fd,
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return thread_pool_submit_aio(pool, aio_worker, acb, cb, opaque);
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}
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static BlockAIOCB *raw_aio_submit(BlockDriverState *bs,
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int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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BlockCompletionFunc *cb, void *opaque, int type)
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static int coroutine_fn raw_co_rw(BlockDriverState *bs, int64_t sector_num,
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int nb_sectors, QEMUIOVector *qiov, int type)
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{
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BDRVRawState *s = bs->opaque;
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if (fd_open(bs) < 0)
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return NULL;
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return -EIO;
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/*
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* Check if the underlying device requires requests to be aligned,
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@ -1345,14 +1344,26 @@ static BlockAIOCB *raw_aio_submit(BlockDriverState *bs,
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type |= QEMU_AIO_MISALIGNED;
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#ifdef CONFIG_LINUX_AIO
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} else if (s->use_aio) {
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return laio_submit(bs, s->aio_ctx, s->fd, sector_num, qiov,
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nb_sectors, cb, opaque, type);
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return laio_co_submit(bs, s->aio_ctx, s->fd, sector_num, qiov,
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nb_sectors, type);
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#endif
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}
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}
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return paio_submit(bs, s->fd, sector_num, qiov, nb_sectors,
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cb, opaque, type);
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return paio_submit_co(bs, s->fd, sector_num * BDRV_SECTOR_SIZE, qiov,
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nb_sectors * BDRV_SECTOR_SIZE, type);
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}
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static int coroutine_fn raw_co_readv(BlockDriverState *bs, int64_t sector_num,
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int nb_sectors, QEMUIOVector *qiov)
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{
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return raw_co_rw(bs, sector_num, nb_sectors, qiov, QEMU_AIO_READ);
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}
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static int coroutine_fn raw_co_writev(BlockDriverState *bs, int64_t sector_num,
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int nb_sectors, QEMUIOVector *qiov)
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{
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return raw_co_rw(bs, sector_num, nb_sectors, qiov, QEMU_AIO_WRITE);
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}
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static void raw_aio_plug(BlockDriverState *bs)
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@ -1375,22 +1386,6 @@ static void raw_aio_unplug(BlockDriverState *bs)
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#endif
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}
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static BlockAIOCB *raw_aio_readv(BlockDriverState *bs,
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int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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BlockCompletionFunc *cb, void *opaque)
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{
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return raw_aio_submit(bs, sector_num, qiov, nb_sectors,
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cb, opaque, QEMU_AIO_READ);
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}
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static BlockAIOCB *raw_aio_writev(BlockDriverState *bs,
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int64_t sector_num, QEMUIOVector *qiov, int nb_sectors,
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BlockCompletionFunc *cb, void *opaque)
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{
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return raw_aio_submit(bs, sector_num, qiov, nb_sectors,
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cb, opaque, QEMU_AIO_WRITE);
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}
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static BlockAIOCB *raw_aio_flush(BlockDriverState *bs,
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BlockCompletionFunc *cb, void *opaque)
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{
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@ -1957,8 +1952,8 @@ BlockDriver bdrv_file = {
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.bdrv_co_get_block_status = raw_co_get_block_status,
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.bdrv_co_pwrite_zeroes = raw_co_pwrite_zeroes,
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.bdrv_aio_readv = raw_aio_readv,
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.bdrv_aio_writev = raw_aio_writev,
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.bdrv_co_readv = raw_co_readv,
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.bdrv_co_writev = raw_co_writev,
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.bdrv_aio_flush = raw_aio_flush,
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.bdrv_aio_discard = raw_aio_discard,
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.bdrv_refresh_limits = raw_refresh_limits,
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@ -2405,8 +2400,8 @@ static BlockDriver bdrv_host_device = {
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.create_opts = &raw_create_opts,
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.bdrv_co_pwrite_zeroes = hdev_co_pwrite_zeroes,
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.bdrv_aio_readv = raw_aio_readv,
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.bdrv_aio_writev = raw_aio_writev,
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.bdrv_co_readv = raw_co_readv,
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.bdrv_co_writev = raw_co_writev,
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.bdrv_aio_flush = raw_aio_flush,
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.bdrv_aio_discard = hdev_aio_discard,
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.bdrv_refresh_limits = raw_refresh_limits,
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@ -2535,8 +2530,8 @@ static BlockDriver bdrv_host_cdrom = {
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.bdrv_create = hdev_create,
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.create_opts = &raw_create_opts,
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.bdrv_aio_readv = raw_aio_readv,
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.bdrv_aio_writev = raw_aio_writev,
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.bdrv_co_readv = raw_co_readv,
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.bdrv_co_writev = raw_co_writev,
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.bdrv_aio_flush = raw_aio_flush,
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.bdrv_refresh_limits = raw_refresh_limits,
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.bdrv_io_plug = raw_aio_plug,
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@ -2670,8 +2665,8 @@ static BlockDriver bdrv_host_cdrom = {
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.bdrv_create = hdev_create,
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.create_opts = &raw_create_opts,
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.bdrv_aio_readv = raw_aio_readv,
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.bdrv_aio_writev = raw_aio_writev,
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.bdrv_co_readv = raw_co_readv,
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.bdrv_co_writev = raw_co_writev,
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.bdrv_aio_flush = raw_aio_flush,
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.bdrv_refresh_limits = raw_refresh_limits,
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.bdrv_io_plug = raw_aio_plug,
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