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>
}
max_bytes = ROUND_UP(MAX(0, total_bytes - offset), align);
- if (bytes < max_bytes) {
+ if (bytes <= max_bytes) {
ret = bdrv_driver_preadv(bs, offset, bytes, qiov, 0);
} else if (max_bytes > 0) {
QEMUIOVector local_qiov;