[ovs-dev] [PATCH 04/10] dpif-linux: Consolidate buffer usage in flow_dump_next().

Ben Pfaff blp at nicira.com
Mon Jan 13 23:52:00 UTC 2014


On Mon, Jan 13, 2014 at 03:50:24PM -0800, Joe Stringer wrote:
> On 13 January 2014 14:28, Ben Pfaff <blp at nicira.com> wrote:
> >
> > Let's allocate at least 4096 bytes (or NL_DUMP_BUFSIZE if we define
> > that) because the kernel always tries to fill up a full 4096 bytes (or
> > 8192 on systems with big pages, but I don't think we care much about
> > those):
> > > -    state->buf = NULL;
> > > +    state->buf = ofpbuf_new(1024);
> >
> 
> OK. I think there are various places that could make use of an
> NL_DUMP_BUFSIZE. I'll fix them up.
> 
> 
> > But I think that this commit has a serious bug: by discarding
> > state->buf and replacing it with a new one, we lose any buffered
> > messages that the next nl_dump_next() would pull out (via
> > nl_msg_next()).
> >
> 
> You're right. I'm pretty sure that all of the code in this patch is
> replaced in later patches anyhow, so I may as well drop it.

Yeah, I figured that you didn't see the bug because it only exists in
the middle of the series.

Dropping it is fine if it works out.



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