ipv4: convert fib_num_tclassid_users to atomic_t

Before commit 7b42b539c204 ("ipv4: Create cleanup helper for fib_nh")
changes to net->ipv4.fib_num_tclassid_users were protected by RTNL.

After the change, this is no longer the case, as free_fib_info_rcu()
runs after rcu grace period, without rtnl being held.

Fixes: 7b42b539c204 ("ipv4: Create cleanup helper for fib_nh")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Ahern <dsahern@kernel.org>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index ab5348e57db1a627cbce2dededb2e9b754d1f2cd..3417ba2d27ad6a1b5612a8855d2788f10d9fdf25 100644 (file)
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -438,7 +438,7 @@ int fib_validate_source(struct sk_buff *skb, __be32 src, __be32 dst,
 #ifdef CONFIG_IP_ROUTE_CLASSID
 static inline int fib_num_tclassid_users(struct net *net)
 {
-       return net->ipv4.fib_num_tclassid_users;
+       return atomic_read(&net->ipv4.fib_num_tclassid_users);
 }
 #else
 static inline int fib_num_tclassid_users(struct net *net)

diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 2f65701a43c953bd3a9a9e3d491882cb7bb11859..6c5b2efc4f17d0d17be750d0c1a2e1d169ec063e 100644 (file)
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -65,7 +65,7 @@ struct netns_ipv4 {
        bool                    fib_has_custom_local_routes;
        bool                    fib_offload_disabled;
 #ifdef CONFIG_IP_ROUTE_CLASSID
-       int                     fib_num_tclassid_users;
+       atomic_t                fib_num_tclassid_users;
 #endif
        struct hlist_head       *fib_table_hash;
        struct sock             *fibnl;

diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 9fe13e4f5d08a5cf9cd9ff15033b9f6e0dc9e492..4d61ddd8a0ecfc4cc47b4802eb5a573beb84ee44 100644 (file)
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1582,7 +1582,7 @@ static int __net_init fib_net_init(struct net *net)
        int error;
 
 #ifdef CONFIG_IP_ROUTE_CLASSID
-       net->ipv4.fib_num_tclassid_users = 0;
+       atomic_set(&net->ipv4.fib_num_tclassid_users, 0);
 #endif
        error = ip_fib_net_init(net);
        if (error < 0)

diff --git a/net/ipv4/fib_rules.c b/net/ipv4/fib_rules.c
index 364ad3446b2f3c056ea5dafea1542e4d3306ddb6..d279cb8ac1584487885f66819634b421c01bf819 100644 (file)
--- a/net/ipv4/fib_rules.c
+++ b/net/ipv4/fib_rules.c
@@ -264,7 +264,7 @@ static int fib4_rule_configure(struct fib_rule *rule, struct sk_buff *skb,
        if (tb[FRA_FLOW]) {
                rule4->tclassid = nla_get_u32(tb[FRA_FLOW]);
                if (rule4->tclassid)
-                       net->ipv4.fib_num_tclassid_users++;
+                       atomic_inc(&net->ipv4.fib_num_tclassid_users);
        }
 #endif
 
@@ -296,7 +296,7 @@ static int fib4_rule_delete(struct fib_rule *rule)
 
 #ifdef CONFIG_IP_ROUTE_CLASSID
        if (((struct fib4_rule *)rule)->tclassid)
-               net->ipv4.fib_num_tclassid_users--;
+               atomic_dec(&net->ipv4.fib_num_tclassid_users);
 #endif
        net->ipv4.fib_has_custom_rules = true;
 

diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 3364cb9c67e018fea2b2e370046de5252581b996..fde7797b580694bb3924c5c6e9560cf04fd67387 100644 (file)
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -220,7 +220,7 @@ void fib_nh_release(struct net *net, struct fib_nh *fib_nh)
 {
 #ifdef CONFIG_IP_ROUTE_CLASSID
        if (fib_nh->nh_tclassid)
-               net->ipv4.fib_num_tclassid_users--;
+               atomic_dec(&net->ipv4.fib_num_tclassid_users);
 #endif
        fib_nh_common_release(&fib_nh->nh_common);
 }
@@ -632,7 +632,7 @@ int fib_nh_init(struct net *net, struct fib_nh *nh,
 #ifdef CONFIG_IP_ROUTE_CLASSID
        nh->nh_tclassid = cfg->fc_flow;
        if (nh->nh_tclassid)
-               net->ipv4.fib_num_tclassid_users++;
+               atomic_inc(&net->ipv4.fib_num_tclassid_users);
 #endif
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
        nh->fib_nh_weight = nh_weight;