Commit ab061f33 authored by Kuniyuki Iwashima's avatar Kuniyuki Iwashima Committed by Jakub Kicinski
Browse files

mpls: Add mpls_dev_rcu(). 



mpls_dev_get() uses rcu_dereference_rtnl() to fetch dev->mpls_ptr.

We will replace RTNL with a dedicated mutex to protect the field.

Then, we will use rcu_dereference_protected() for clarity.

Let's add mpls_dev_rcu() for the RCU reader.

Signed-off-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: default avatarGuillaume Nault <gnault@redhat.com>
Link: https://patch.msgid.link/20251029173344.2934622-7-kuniyu@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent bc7ebc56

net/mpls/af_mpls.c

+6 −6
Original line number Diff line number Diff line
@@ -136,7 +136,7 @@ void mpls_stats_inc_outucastpkts(struct net *net, 
	struct mpls_dev *mdev;



	if (skb->protocol == htons(ETH_P_MPLS_UC)) {

		mdev = mpls_dev_get(dev);

		mdev = mpls_dev_rcu(dev);

		if (mdev)

			MPLS_INC_STATS_LEN(mdev, skb->len,

					   tx_packets,
@@ -358,7 +358,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev, 


	/* Careful this entire function runs inside of an rcu critical section */



	mdev = mpls_dev_get(dev);

	mdev = mpls_dev_rcu(dev);

	if (!mdev)

		goto drop;
@@ -467,7 +467,7 @@ static int mpls_forward(struct sk_buff *skb, struct net_device *dev, 
	return 0;



tx_err:

	out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;

	out_mdev = out_dev ? mpls_dev_rcu(out_dev) : NULL;

	if (out_mdev)

		MPLS_INC_STATS(out_mdev, tx_errors);

	goto drop;
@@ -1118,7 +1118,7 @@ static int mpls_fill_stats_af(struct sk_buff *skb, 
	struct mpls_dev *mdev;

	struct nlattr *nla;



	mdev = mpls_dev_get(dev);

	mdev = mpls_dev_rcu(dev);

	if (!mdev)

		return -ENODATA;
@@ -1138,7 +1138,7 @@ static size_t mpls_get_stats_af_size(const struct net_device *dev) 
{

	struct mpls_dev *mdev;



	mdev = mpls_dev_get(dev);

	mdev = mpls_dev_rcu(dev);

	if (!mdev)

		return 0;
@@ -1341,7 +1341,7 @@ static int mpls_netconf_dump_devconf(struct sk_buff *skb, 


	rcu_read_lock();

	for_each_netdev_dump(net, dev, ctx->ifindex) {

		mdev = mpls_dev_get(dev);

		mdev = mpls_dev_rcu(dev);

		if (!mdev)

			continue;

		err = mpls_netconf_fill_devconf(skb, mdev,

net/mpls/internal.h

+5 −0
Original line number Diff line number Diff line
@@ -185,6 +185,11 @@ static inline struct mpls_entry_decoded mpls_entry_decode(struct mpls_shim_hdr * 
	return result;

}



static inline struct mpls_dev *mpls_dev_rcu(const struct net_device *dev)

{

	return rcu_dereference(dev->mpls_ptr);

}



static inline struct mpls_dev *mpls_dev_get(const struct net_device *dev)

{

	return rcu_dereference_rtnl(dev->mpls_ptr);

net/mpls/mpls_iptunnel.c

+1 −1
Original line number Diff line number Diff line
@@ -153,7 +153,7 @@ static int mpls_xmit(struct sk_buff *skb) 
	return LWTUNNEL_XMIT_DONE;



drop:

	out_mdev = out_dev ? mpls_dev_get(out_dev) : NULL;

	out_mdev = out_dev ? mpls_dev_rcu(out_dev) : NULL;

	if (out_mdev)

		MPLS_INC_STATS(out_mdev, tx_errors);

	kfree_skb(skb);