Re: [PATCH 20/29] tools/libxl: Update datacopier to support sending data only

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 11/09/14 13:39, Ian Campbell wrote:
> On Thu, 2014-09-11 at 13:00 +0100, Andrew Cooper wrote:
>> On 11/09/14 12:56, Ian Campbell wrote:
>>> On Wed, 2014-09-10 at 18:10 +0100, Andrew Cooper wrote:
>>>> From: Wen Congyang <wency@cn.fujitsu.com>
>>>>
>>>> datacopier is to read some data and write it out. If we
>>>> have some data to send it over network, we cannot use
>>>> datacopier. Update it to support this case.
>>> I'm afraid I'm not sure what this changelog is saying. If we have data
>>> to send over the network then why can't we use datacopier? How does
>>> making this conditional on readfd's validity help that case?
>> datacopier was originally strictly copying data from infd to outfd,
>> until EOF.
>>
>> These patches around here in the series extend datacopier to include
>> "please write this local buffer to outfd", "please read $N bytes from
>> infd to this local buffer", and "please copy exactly $N bytes from infd
>> to outfd", all as asynchronous operations.
> Thanks, that all needs to be clearly explained in the commit log.
>
> I'm going to leave it to Ian to decide if this is an acceptable
> repurposing of the datacopier infrastructure.
>
> Ian.
>

Ian explicitly requested modification of datacopier in preference to
adding similar infrastructure with a different name, when I talked to
him in person.

~Andrew