to #28170604

commit 3f9d64415fdaa73017fcb168930006648617b488 upstream

Ensure we keep the truncated value, if we did truncate it. If not, we
might read/write more than the registered buffer size.

Also for retry, ensure that we return the truncated mapped value for
the vectorized versions of the read/write commands.
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Acked-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Signed-off-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>