mirror of https://github.com/proxmox/mirror_qemu
block: Fix harmless off-by-one in bdrv_aligned_preadv()
If the amount of data to read ends exactly on the total size of the bs, then we were wasting time creating a local qiov to read the data in preparation for what would normally be appending zeroes beyond the end, even though this corner case has nothing further to do. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>master
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a604fa2ba5
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@ -1036,7 +1036,7 @@ static int coroutine_fn bdrv_aligned_preadv(BlockDriverState *bs,
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}
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max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
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if (bytes < max_bytes) {
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if (bytes <= max_bytes) {
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ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0);
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} else if (max_bytes > 0) {
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QEMUIOVector local_qiov;
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