Re: [PATCH] nl80211: Reset split_start on error path when split dump is not used

[Johannes Berg <johannes@sipsolutions.net>]

On Thu, 2014-01-16 at 14:50 +0100, Pontus Fuchs wrote:
> On 2014-01-16 14:41, Johannes Berg wrote:
> > On Thu, 2014-01-16 at 14:34 +0100, Pontus Fuchs wrote:
> >> When the netlink skb is exhausted split_start is left set. In the
> >> subsequent retry, with a larger buffer, the dump is continued from the
> >> failing point instead of from the beginning.
> >
> > Hmm. Maybe it should be like this instead?
> >
> > johannes
> >
> > diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c
> > index 138dc3b..2e08af5 100644
> > --- a/net/wireless/nl80211.c
> > +++ b/net/wireless/nl80211.c
> > @@ -1680,6 +1680,7 @@ static int nl80211_dump_wiphy(struct sk_buff *skb, struct netlink_callback *cb)
> >   				    !skb->len &&
> >   				    cb->min_dump_alloc < 4096) {
> >   					cb->min_dump_alloc = 4096;
> > +					state->split_start = 0;
> >   					rtnl_unlock();
> >   					return 1;
> >   				}
> 
> Will that not cause problem if split scan is in use and one of the split 
> chunks needs to be resent due to EMSGSIZE?

That's not supposed to happen, and the "!skb->len" check should catch
it.

johannes