Re: [PATCH v2 4/4] splice: fix updating sd->pos wrongly

Changli Gao
2010-05-28T11:37:06Z

On Fri, May 28, 2010 at 7:11 PM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> On Fri, 28 May 2010, Changli Gao wrote:
>>  Before checking the sd->pos, sd->pos
>> already is updated with the value returned by splice_read(), so if in
>> file is seekabble, sd->pos is non-zero when I checking it.
>
> I see the logic now.  But it's really confusing, at least some
> comments would be needed.
>
> But I think it would be better not to try reusing sd->pos for reading,
> but supplying an "loff_t *read_ppos" to splice_direct_to_actor and
> leaving sd->pos alone (for the write side to use and update as
> necessary).
>

if (ret < read_len) {

I think is much like a hack too. :)

- sd->pos = prev_pos + ret;
+ if (sd->pos)
+ sd->pos = prev_pos + ret;
goto out_release;
}

Anyway, it can fix the issue I mentioned above. Any future cleanup
should not be mixed in, IMO.

--
Regards，
Changli Gao(xiaosuo@gmail.com)