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Message-Id: <20220622051255.700309-11-edumazet@google.com>
Date: Wed, 22 Jun 2022 05:12:46 +0000
From: Eric Dumazet <edumazet@...gle.com>
To: "David S . Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: netdev@...r.kernel.org, eric.dumazet@...il.com,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH net-next 10/19] 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 <edumazet@...gle.com>
---
net/ipv6/ip6mr.c | 35 ++++++++++++++++++++---------------
1 file changed, 20 insertions(+), 15 deletions(-)
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c
index 44cb3d88bbd6f85ce0c8e9054dd3d578b7b3733b..a6d97952bf5306c245996c612107d0c851bbc822 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;
--
2.37.0.rc0.104.g0611611a94-goog
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