[MCAST]: Fix filter leak on device removal.

This fixes source filter leakage when a device is removed and a
process leaves the group thereafter.

This also includes corresponding fixes for IPv6 multicast source
filters on device removal.

Signed-off-by: David L Stevens <dlstevens@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/igmp.c b/net/ipv4/igmp.c
index e981369..8e8117c 100644
--- a/net/ipv4/igmp.c
+++ b/net/ipv4/igmp.c
@@ -1793,29 +1793,35 @@
 	struct in_device *in_dev;
 	u32 group = imr->imr_multiaddr.s_addr;
 	u32 ifindex;
+	int ret = -EADDRNOTAVAIL;
 
 	rtnl_lock();
 	in_dev = ip_mc_find_dev(imr);
-	if (!in_dev) {
-		rtnl_unlock();
-		return -ENODEV;
-	}
 	ifindex = imr->imr_ifindex;
 	for (imlp = &inet->mc_list; (iml = *imlp) != NULL; imlp = &iml->next) {
-		if (iml->multi.imr_multiaddr.s_addr == group &&
-		    iml->multi.imr_ifindex == ifindex) {
-			(void) ip_mc_leave_src(sk, iml, in_dev);
+		if (iml->multi.imr_multiaddr.s_addr != group)
+			continue;
+		if (ifindex) {
+			if (iml->multi.imr_ifindex != ifindex)
+				continue;
+		} else if (imr->imr_address.s_addr && imr->imr_address.s_addr !=
+				iml->multi.imr_address.s_addr)
+			continue;
 
-			*imlp = iml->next;
+		(void) ip_mc_leave_src(sk, iml, in_dev);
 
+		*imlp = iml->next;
+
+		if (in_dev)
 			ip_mc_dec_group(in_dev, group);
-			rtnl_unlock();
-			sock_kfree_s(sk, iml, sizeof(*iml));
-			return 0;
-		}
+		rtnl_unlock();
+		sock_kfree_s(sk, iml, sizeof(*iml));
+		return 0;
 	}
+	if (!in_dev)
+		ret = -ENODEV;
 	rtnl_unlock();
-	return -EADDRNOTAVAIL;
+	return ret;
 }
 
 int ip_mc_source(int add, int omode, struct sock *sk, struct