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

Changli Gao
2010-05-29T14:23:18Z

On Sat, May 29, 2010 at 10:09 PM, Jamie Lokier <jamie@shareable.org> wrote:
>
> Not true if the "file" is /dev/mem or /dev/kmem.  The starting offset
> can be negative, so can end at zero.
>
> It's an obscure case and I don't know if you can sendfile from
> /dev/{,k}mem anyway :-) but illustrates why sd->pos != 0 is dubious.
>

So the safe way is checking if splice_read() updates pos or not, isn't it?

if (sd->pos != prev_pos)
sd->pos = prev_pos + ret;

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