Commit 46a94e44 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

ipv6: ip6_mc_input() and ip6_mr_input() cleanups 



Both functions are always called under RCU.

We remove the extra rcu_read_lock()/rcu_read_unlock().

We use skb_dst_dev_net_rcu() instead of skb_dst_dev_net().

We use dev_net_rcu() instead of dev_net().

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-11-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 93d1cff3

net/ipv6/ip6_input.c

+11 −18
Original line number Diff line number Diff line
@@ -501,38 +501,32 @@ EXPORT_SYMBOL_GPL(ip6_input); 


int ip6_mc_input(struct sk_buff *skb)

{

	struct net_device *dev = skb->dev;

	int sdif = inet6_sdif(skb);

	const struct ipv6hdr *hdr;

	struct net_device *dev;

	bool deliver;



	__IP6_UPD_PO_STATS(skb_dst_dev_net(skb),

			 __in6_dev_get_safely(skb->dev), IPSTATS_MIB_INMCAST,

	__IP6_UPD_PO_STATS(skb_dst_dev_net_rcu(skb),

			   __in6_dev_get_safely(dev), IPSTATS_MIB_INMCAST,

			   skb->len);



	/* skb->dev passed may be master dev for vrfs. */

	if (sdif) {

		rcu_read_lock();

		dev = dev_get_by_index_rcu(dev_net(skb->dev), sdif);

		dev = dev_get_by_index_rcu(dev_net_rcu(dev), sdif);

		if (!dev) {

			rcu_read_unlock();

			kfree_skb(skb);

			return -ENODEV;

		}

	} else {

		dev = skb->dev;

	}



	hdr = ipv6_hdr(skb);

	deliver = ipv6_chk_mcast_addr(dev, &hdr->daddr, NULL);

	if (sdif)

		rcu_read_unlock();



#ifdef CONFIG_IPV6_MROUTE

	/*

	 *      IPv6 multicast router mode is now supported ;)

	 */

	if (atomic_read(&dev_net(skb->dev)->ipv6.devconf_all->mc_forwarding) &&

	if (atomic_read(&dev_net_rcu(skb->dev)->ipv6.devconf_all->mc_forwarding) &&

	    !(ipv6_addr_type(&hdr->daddr) &

	      (IPV6_ADDR_LOOPBACK|IPV6_ADDR_LINKLOCAL)) &&

	    likely(!(IP6CB(skb)->flags & IP6SKB_FORWARDED))) {
@@ -573,22 +567,21 @@ int ip6_mc_input(struct sk_buff *skb) 
			/* unknown RA - process it normally */

		}



		if (deliver)

		if (deliver) {

			skb2 = skb_clone(skb, GFP_ATOMIC);

		else {

		} else {

			skb2 = skb;

			skb = NULL;

		}



		if (skb2) {

		if (skb2)

			ip6_mr_input(skb2);

	}

	}

out:

#endif

	if (likely(deliver))

	if (likely(deliver)) {

		ip6_input(skb);

	else {

	} else {

		/* discard */

		kfree_skb(skb);

	}

net/ipv6/ip6mr.c

+4 −5
Original line number Diff line number Diff line
@@ -2301,21 +2301,20 @@ static void ip6_mr_output_finish(struct net *net, struct mr_table *mrt, 


int ip6_mr_input(struct sk_buff *skb)

{

	struct net_device *dev = skb->dev;

	struct net *net = dev_net_rcu(dev);

	struct mfc6_cache *cache;

	struct net *net = dev_net(skb->dev);

	struct mr_table *mrt;

	struct flowi6 fl6 = {

		.flowi6_iif	= skb->dev->ifindex,

		.flowi6_iif	= dev->ifindex,

		.flowi6_mark	= skb->mark,

	};

	int err;

	struct net_device *dev;



	/* skb->dev passed in is the master dev for vrfs.

	 * Get the proper interface that does have a vif associated with it.

	 */

	dev = skb->dev;

	if (netif_is_l3_master(skb->dev)) {

	if (netif_is_l3_master(dev)) {

		dev = dev_get_by_index_rcu(net, IPCB(skb)->iif);

		if (!dev) {

			kfree_skb(skb);