Re: [PATCH v8 1/5] QIOChannel: Add flags on io_writev and introduce io_flush callback

[Juan Quintela <quintela@redhat.com>]

Leonardo Bras <leobras@redhat.com> wrote:
> Add flags to io_writev and introduce io_flush as optional callback to
> QIOChannelClass, allowing the implementation of zero copy writes by
> subclasses.
>
> How to use them:
> - Write data using qio_channel_writev*(...,QIO_CHANNEL_WRITE_FLAG_ZERO_COPY),
> - Wait write completion with qio_channel_flush().
>
> Notes:
> As some zero copy write implementations work asynchronously, it's
> recommended to keep the write buffer untouched until the return of
> qio_channel_flush(), to avoid the risk of sending an updated buffer
> instead of the buffer state during write.
>
> As io_flush callback is optional, if a subclass does not implement it, then:
> - io_flush will return 0 without changing anything.
>
> Also, some functions like qio_channel_writev_full_all() were adapted to
> receive a flag parameter. That allows shared code between zero copy and
> non-zero copy writev, and also an easier implementation on new flags.
>
> Signed-off-by: Leonardo Bras <leobras@redhat.com>

Reviewed-by: Juan Quintela <quintela@redhat.com>

As everybody pointed out about the missing assertion...