Commit 64667988 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipmr: ipmr_cache_report() changes 



ipmr_cache_report() first argument can be marked const, and we change
the caller convention about which lock needs to be held.

Instead of read_lock(&mrt_lock), we can use rcu_read_lock().

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0b490b51

net/ipv4/ipmr.c

+29 −16
Original line number Diff line number Diff line
@@ -106,7 +106,7 @@ static void ipmr_free_table(struct mr_table *mrt); 
static void ip_mr_forward(struct net *net, struct mr_table *mrt,

			  struct net_device *dev, struct sk_buff *skb,

			  struct mfc_cache *cache, int local);

static int ipmr_cache_report(struct mr_table *mrt,

static int ipmr_cache_report(const struct mr_table *mrt,

			     struct sk_buff *pkt, vifi_t vifi, int assert);

static void mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc,

				 int cmd);
@@ -507,11 +507,15 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb, struct net_device *dev) 
		return err;

	}



	read_lock(&mrt_lock);

	dev->stats.tx_bytes += skb->len;

	dev->stats.tx_packets++;

	ipmr_cache_report(mrt, skb, mrt->mroute_reg_vif_num, IGMPMSG_WHOLEPKT);

	read_unlock(&mrt_lock);

	rcu_read_lock();



	/* Pairs with WRITE_ONCE() in vif_add() and vif_delete() */

	ipmr_cache_report(mrt, skb, READ_ONCE(mrt->mroute_reg_vif_num),

			  IGMPMSG_WHOLEPKT);



	rcu_read_unlock();

	kfree_skb(skb);

	return NETDEV_TX_OK;

}
@@ -665,9 +669,10 @@ static int vif_delete(struct mr_table *mrt, int vifi, int notify, 
				      vifi, mrt->id);

	RCU_INIT_POINTER(v->dev, NULL);



	if (vifi == mrt->mroute_reg_vif_num)

		mrt->mroute_reg_vif_num = -1;



	if (vifi == mrt->mroute_reg_vif_num) {

		/* Pairs with READ_ONCE() in ipmr_cache_report() and reg_vif_xmit() */

		WRITE_ONCE(mrt->mroute_reg_vif_num, -1);

	}

	if (vifi + 1 == mrt->maxvif) {

		int tmp;
@@ -895,8 +900,10 @@ static int vif_add(struct net *net, struct mr_table *mrt, 
	write_lock_bh(&mrt_lock);

	rcu_assign_pointer(v->dev, dev);

	netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC);

	if (v->flags & VIFF_REGISTER)

		mrt->mroute_reg_vif_num = vifi;

	if (v->flags & VIFF_REGISTER) {

		/* Pairs with READ_ONCE() in ipmr_cache_report() and reg_vif_xmit() */

		WRITE_ONCE(mrt->mroute_reg_vif_num, vifi);

	}

	if (vifi+1 > mrt->maxvif)

		mrt->maxvif = vifi+1;

	write_unlock_bh(&mrt_lock);
@@ -1005,9 +1012,9 @@ static void ipmr_cache_resolve(struct net *net, struct mr_table *mrt, 


/* Bounce a cache query up to mrouted and netlink.

 *

 * Called under mrt_lock.

 * Called under rcu_read_lock().

 */

static int ipmr_cache_report(struct mr_table *mrt,

static int ipmr_cache_report(const struct mr_table *mrt,

			     struct sk_buff *pkt, vifi_t vifi, int assert)

{

	const int ihl = ip_hdrlen(pkt);
@@ -1042,8 +1049,11 @@ static int ipmr_cache_report(struct mr_table *mrt, 
			msg->im_vif = vifi;

			msg->im_vif_hi = vifi >> 8;

		} else {

			msg->im_vif = mrt->mroute_reg_vif_num;

			msg->im_vif_hi = mrt->mroute_reg_vif_num >> 8;

			/* Pairs with WRITE_ONCE() in vif_add() and vif_delete() */

			int vif_num = READ_ONCE(mrt->mroute_reg_vif_num);



			msg->im_vif = vif_num;

			msg->im_vif_hi = vif_num >> 8;

		}

		ip_hdr(skb)->ihl = sizeof(struct iphdr) >> 2;

		ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(pkt)->tot_len) +
@@ -1068,10 +1078,8 @@ static int ipmr_cache_report(struct mr_table *mrt, 
		skb->transport_header = skb->network_header;

	}



	rcu_read_lock();

	mroute_sk = rcu_dereference(mrt->mroute_sk);

	if (!mroute_sk) {

		rcu_read_unlock();

		kfree_skb(skb);

		return -EINVAL;

	}
@@ -1080,7 +1088,7 @@ static int ipmr_cache_report(struct mr_table *mrt, 


	/* Deliver to mrouted */

	ret = sock_queue_rcv_skb(mroute_sk, skb);

	rcu_read_unlock();



	if (ret < 0) {

		net_warn_ratelimited("mroute: pending queue full, dropping entries\n");

		kfree_skb(skb);
@@ -1090,6 +1098,7 @@ static int ipmr_cache_report(struct mr_table *mrt, 
}



/* Queue a packet for resolution. It gets locked cache entry! */

/* Called under rcu_read_lock() */

static int ipmr_cache_unresolved(struct mr_table *mrt, vifi_t vifi,

				 struct sk_buff *skb, struct net_device *dev)

{
@@ -1830,7 +1839,9 @@ static void ipmr_queue_xmit(struct net *net, struct mr_table *mrt, 
		vif->bytes_out += skb->len;

		vif_dev->stats.tx_bytes += skb->len;

		vif_dev->stats.tx_packets++;

		rcu_read_lock();

		ipmr_cache_report(mrt, skb, vifi, IGMPMSG_WHOLEPKT);

		rcu_read_unlock();

		goto out_free;

	}
@@ -1980,10 +1991,12 @@ static void ip_mr_forward(struct net *net, struct mr_table *mrt, 
			       c->_c.mfc_un.res.last_assert +

			       MFC_ASSERT_THRESH)) {

			c->_c.mfc_un.res.last_assert = jiffies;

			rcu_read_lock();

			ipmr_cache_report(mrt, skb, true_vifi, IGMPMSG_WRONGVIF);

			if (mrt->mroute_do_wrvifwhole)

				ipmr_cache_report(mrt, skb, true_vifi,

						  IGMPMSG_WRVIFWHOLE);

			rcu_read_unlock();

		}

		goto dont_forward;

	}