From 3493a5b730e5c0dfecb445e56a4ad36a36819ba9 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 23 Jun 2022 04:34:40 +0000 Subject: ip6mr: ip6mr_cache_report() changes ip6mr_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: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv6/ip6mr.c | 35 ++++++++++++++++++++--------------- 1 file changed, 20 insertions(+), 15 deletions(-) (limited to 'net/ipv6/ip6mr.c') diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 44cb3d88bbd6..a6d97952bf53 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -91,11 +91,11 @@ static void ip6mr_free_table(struct mr_table *mrt); static void ip6_mr_forward(struct net *net, struct mr_table *mrt, struct net_device *dev, struct sk_buff *skb, struct mfc6_cache *cache); -static int ip6mr_cache_report(struct mr_table *mrt, struct sk_buff *pkt, +static int ip6mr_cache_report(const struct mr_table *mrt, struct sk_buff *pkt, mifi_t mifi, int assert); static void mr6_netlink_event(struct mr_table *mrt, struct mfc6_cache *mfc, int cmd); -static void mrt6msg_netlink_event(struct mr_table *mrt, struct sk_buff *pkt); +static void mrt6msg_netlink_event(const struct mr_table *mrt, struct sk_buff *pkt); static int ip6mr_rtm_dumproute(struct sk_buff *skb, struct netlink_callback *cb); static void mroute_clean_tables(struct mr_table *mrt, int flags); @@ -608,11 +608,12 @@ static netdev_tx_t reg_vif_xmit(struct sk_buff *skb, if (ip6mr_fib_lookup(net, &fl6, &mrt) < 0) goto tx_err; - read_lock(&mrt_lock); dev->stats.tx_bytes += skb->len; dev->stats.tx_packets++; - ip6mr_cache_report(mrt, skb, mrt->mroute_reg_vif_num, MRT6MSG_WHOLEPKT); - read_unlock(&mrt_lock); + rcu_read_lock(); + ip6mr_cache_report(mrt, skb, READ_ONCE(mrt->mroute_reg_vif_num), + MRT6MSG_WHOLEPKT); + rcu_read_unlock(); kfree_skb(skb); return NETDEV_TX_OK; @@ -718,8 +719,10 @@ static int mif6_delete(struct mr_table *mrt, int vifi, int notify, RCU_INIT_POINTER(v->dev, NULL); #ifdef CONFIG_IPV6_PIMSM_V2 - 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 ip6mr_cache_report() and reg_vif_xmit() */ + WRITE_ONCE(mrt->mroute_reg_vif_num, -1); + } #endif if (vifi + 1 == mrt->maxvif) { @@ -922,7 +925,7 @@ static int mif6_add(struct net *net, struct mr_table *mrt, netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC); #ifdef CONFIG_IPV6_PIMSM_V2 if (v->flags & MIFF_REGISTER) - mrt->mroute_reg_vif_num = vifi; + WRITE_ONCE(mrt->mroute_reg_vif_num, vifi); #endif if (vifi + 1 > mrt->maxvif) mrt->maxvif = vifi + 1; @@ -1033,10 +1036,10 @@ static void ip6mr_cache_resolve(struct net *net, struct mr_table *mrt, /* * Bounce a cache query up to pim6sd and netlink. * - * Called under mrt_lock. + * Called under rcu_read_lock() */ -static int ip6mr_cache_report(struct mr_table *mrt, struct sk_buff *pkt, +static int ip6mr_cache_report(const struct mr_table *mrt, struct sk_buff *pkt, mifi_t mifi, int assert) { struct sock *mroute6_sk; @@ -1077,7 +1080,7 @@ static int ip6mr_cache_report(struct mr_table *mrt, struct sk_buff *pkt, if (assert == MRT6MSG_WRMIFWHOLE) msg->im6_mif = mifi; else - msg->im6_mif = mrt->mroute_reg_vif_num; + msg->im6_mif = READ_ONCE(mrt->mroute_reg_vif_num); msg->im6_pad = 0; msg->im6_src = ipv6_hdr(pkt)->saddr; msg->im6_dst = ipv6_hdr(pkt)->daddr; @@ -1112,10 +1115,8 @@ static int ip6mr_cache_report(struct mr_table *mrt, struct sk_buff *pkt, skb->ip_summed = CHECKSUM_UNNECESSARY; } - rcu_read_lock(); mroute6_sk = rcu_dereference(mrt->mroute_sk); if (!mroute6_sk) { - rcu_read_unlock(); kfree_skb(skb); return -EINVAL; } @@ -1124,7 +1125,7 @@ static int ip6mr_cache_report(struct mr_table *mrt, struct sk_buff *pkt, /* Deliver to user space multicast routing algorithms */ ret = sock_queue_rcv_skb(mroute6_sk, skb); - rcu_read_unlock(); + if (ret < 0) { net_warn_ratelimited("mroute6: pending queue full, dropping entries\n"); kfree_skb(skb); @@ -2042,7 +2043,9 @@ static int ip6mr_forward2(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(); ip6mr_cache_report(mrt, skb, vifi, MRT6MSG_WHOLEPKT); + rcu_read_unlock(); goto out_free; } #endif @@ -2155,10 +2158,12 @@ static void ip6_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(); ip6mr_cache_report(mrt, skb, true_vifi, MRT6MSG_WRONGMIF); if (mrt->mroute_do_wrvifwhole) ip6mr_cache_report(mrt, skb, true_vifi, MRT6MSG_WRMIFWHOLE); + rcu_read_unlock(); } goto dont_forward; } @@ -2465,7 +2470,7 @@ static size_t mrt6msg_netlink_msgsize(size_t payloadlen) return len; } -static void mrt6msg_netlink_event(struct mr_table *mrt, struct sk_buff *pkt) +static void mrt6msg_netlink_event(const struct mr_table *mrt, struct sk_buff *pkt) { struct net *net = read_pnet(&mrt->net); struct nlmsghdr *nlh; -- cgit v1.2.3