Re: [PATCH] nefilter: nfnetlink: add nfnetlink_set_err and use it in ctnetlink

[Pablo Neira Ayuso <pablo@netfilter.org>]

Patrick McHardy wrote:
> Pablo Neira Ayuso wrote:
>> This patch adds nfnetlink_set_err() to propagate the error to netlink
>> broadcast listener in case of memory allocation errors in the
>> message building.
> 
>> +void nfnetlink_set_err(u32 group, int error)
>> +{
>> +    netlink_set_err(nfnl, 0, group, error);
>> +}
>> +EXPORT_SYMBOL_GPL(nfnetlink_set_err);
> 
> Please make the pid argument controllable by the caller as well. This
> is necessary to avoid double error notifications when an error occurs
> in response to a user-request triggering notifications.

OK, I'll add it, but the pid passed as argument will be zero by now.
Note that, in the current code, user-requests ignore notification
errors, so there is no chance to get double error notifications.

I have another patch here to propagate errors of user-requests that
result in failing notifications, then the pid parameter in
nfnetlink_set_err() will be useful. That patch also includes the use of
NETLINK_BROADCAST_ERROR. I'll send you that patch soon.

-- 
"Los honestos son inadaptados sociales" -- Les Luthiers