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block/io: bdrv_co_do_copy_on_readv: use and support qiov_offset

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Use and support new API in bdrv_co_do_copy_on_readv. Note that in case
of allocated-in-top we need to shrink read size to MIN(..) by hand, as
pre-patch this was actually done implicitly by qemu_iovec_concat (and
we used local_qiov.size).

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20190604161514.262241-6-vsementsov@virtuozzo.com
Message-Id: <20190604161514.262241-6-vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Vladimir Sementsov-Ogievskiy 2019-06-04 19:15:07 +03:00 committed by Stefan Hajnoczi
parent ac850bf099
commit 1143ec5ebf
1 changed files with 9 additions and 9 deletions
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18
block/io.c
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@ -1227,7 +1227,7 @@ bdrv_driver_pwritev_compressed(BlockDriverState *bs, uint64_t offset,
static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
int64_t offset, unsigned int bytes, QEMUIOVector *qiov,
int flags)
size_t qiov_offset, int flags)
{
BlockDriverState *bs = child->bs;
@ -1239,7 +1239,6 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
void *bounce_buffer;
BlockDriver *drv = bs->drv;
QEMUIOVector local_qiov;
int64_t cluster_offset;
int64_t cluster_bytes;
size_t skip_bytes;
@ -1302,6 +1301,8 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
assert(skip_bytes < pnum);
if (ret <= 0) {
QEMUIOVector local_qiov;
/* Must copy-on-read; use the bounce buffer */
pnum = MIN(pnum, MAX_BOUNCE_BUFFER);
qemu_iovec_init_buf(&local_qiov, bounce_buffer, pnum);
@ -1339,16 +1340,15 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
}
if (!(flags & BDRV_REQ_PREFETCH)) {
qemu_iovec_from_buf(qiov, progress, bounce_buffer + skip_bytes,
qemu_iovec_from_buf(qiov, qiov_offset + progress,
bounce_buffer + skip_bytes,
pnum - skip_bytes);
}
} else if (!(flags & BDRV_REQ_PREFETCH)) {
/* Read directly into the destination */
qemu_iovec_init(&local_qiov, qiov->niov);
qemu_iovec_concat(&local_qiov, qiov, progress, pnum - skip_bytes);
ret = bdrv_driver_preadv(bs, offset + progress, local_qiov.size,
&local_qiov, 0, 0);
qemu_iovec_destroy(&local_qiov);
ret = bdrv_driver_preadv(bs, offset + progress,
MIN(pnum - skip_bytes, bytes - progress),
qiov, qiov_offset + progress, 0);
if (ret < 0) {
goto err;
}
@ -1422,7 +1422,7 @@ static int coroutine_fn bdrv_aligned_preadv(BdrvChild *child,
}
if (!ret || pnum != bytes) {
ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, flags);
ret = bdrv_co_do_copy_on_readv(child, offset, bytes, qiov, 0, flags);
goto out;
} else if (flags & BDRV_REQ_PREFETCH) {
goto out;