igmp: Avoid zero delay when receiving odd mixture of IGMP queries

Commit 5b7c84066733c5dfb0e4016d939757b38de189e4 ('ipv4: correct IGMP
behavior on v3 query during v2-compatibility mode') added yet another
case for query parsing, which can result in max_delay = 0.  Substitute
a value of 1, as in the usual v3 case.

Reported-by: Simon McVittie <smcv@debian.org>
References: http://bugs.debian.org/654876
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
static void igmpv3_clear_delrec(struct in_device *in_dev)
{
	struct ip_mc_list *pmc, *nextpmc;

	spin_lock_bh(&in_dev->mc_tomb_lock);
	pmc = in_dev->mc_tomb;
	in_dev->mc_tomb = NULL;
	spin_unlock_bh(&in_dev->mc_tomb_lock);

	for (; pmc; pmc = nextpmc) {
		nextpmc = pmc->next;
		ip_mc_clear_src(pmc);
		in_dev_put(pmc->interface);
		kfree(pmc);
	}
	/* clear dead sources, too */
	rcu_read_lock();
	for_each_pmc_rcu(in_dev, pmc) {
		struct ip_sf_list *psf, *psf_next;

		spin_lock_bh(&pmc->lock);
		psf = pmc->tomb;
		pmc->tomb = NULL;
		spin_unlock_bh(&pmc->lock);
		for (; psf; psf=psf_next) {
			psf_next = psf->sf_next;
			kfree(psf);
		}
	}
	rcu_read_unlock();
}

static void igmpv3_clear_delrec(struct in_device *in_dev)
{
	struct ip_mc_list *pmc, *nextpmc;

	spin_lock_bh(&in_dev->mc_tomb_lock);
	pmc = in_dev->mc_tomb;
	in_dev->mc_tomb = NULL;
	spin_unlock_bh(&in_dev->mc_tomb_lock);

	for (; pmc; pmc = nextpmc) {
		nextpmc = pmc->next;
		ip_mc_clear_src(pmc);
		in_dev_put(pmc->interface);
		kfree(pmc);
	}
	/* clear dead sources, too */
	rcu_read_lock();
	for_each_pmc_rcu(in_dev, pmc) {
		struct ip_sf_list *psf, *psf_next;

		spin_lock_bh(&pmc->lock);
		psf = pmc->tomb;
		pmc->tomb = NULL;
		spin_unlock_bh(&pmc->lock);
		for (; psf; psf=psf_next) {
			psf_next = psf->sf_next;
			kfree(psf);
		}
	}
	rcu_read_unlock();
}
