ipv6 flowlabel: Convert np->ipv6_fl_list to RCU.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 42 insertions, 33 deletions

diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index e971e3742172..850e95bc766c 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -214,7 +214,7 @@ struct ipv6_pinfo {
 
         struct ipv6_mc_socklist __rcu *ipv6_mc_list;
         struct ipv6_ac_socklist *ipv6_ac_list;
-        struct ipv6_fl_socklist *ipv6_fl_list;
+        struct ipv6_fl_socklist __rcu *ipv6_fl_list;
 
         struct ipv6_txoptions   *opt;
         struct sk_buff          *pktoptions;
diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 1d457161def2..851d5412a299 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -239,6 +239,7 @@ struct ip6_flowlabel {
 struct ipv6_fl_socklist {
         struct ipv6_fl_socklist *next;
         struct ip6_flowlabel    *fl;
+        struct rcu_head         rcu;
 };
 
 extern struct ip6_flowlabel     *fl6_sock_lookup(struct sock *sk, __be32 label);
diff --git a/net/ipv6/ip6_flowlabel.c b/net/ipv6/ip6_flowlabel.c
index da156015d827..22494afd981c 100644
--- a/net/ipv6/ip6_flowlabel.c
+++ b/net/ipv6/ip6_flowlabel.c
@@ -62,7 +62,7 @@ static DEFINE_SPINLOCK(ip6_fl_lock);
 
 /* Big socket sock */
 
-static DEFINE_RWLOCK(ip6_sk_fl_lock);
+static DEFINE_SPINLOCK(ip6_sk_fl_lock);
 
 #define for_each_fl_rcu(hash, fl)                               \
         for (fl = rcu_dereference(fl_ht[(hash)]);               \
@@ -73,6 +73,11 @@ static DEFINE_RWLOCK(ip6_sk_fl_lock);
              fl != NULL;                                        \
              fl = rcu_dereference(fl->next))
 
+#define for_each_sk_fl_rcu(np, sfl)                             \
+        for (sfl = rcu_dereference_bh(np->ipv6_fl_list);        \
+             sfl != NULL;                                       \
+             sfl = rcu_dereference_bh(sfl->next))
+
 static inline struct ip6_flowlabel *__fl_lookup(struct net *net, __be32 label)
 {
         struct ip6_flowlabel *fl;
@@ -244,17 +249,17 @@ struct ip6_flowlabel * fl6_sock_lookup(struct sock *sk, __be32 label)
 
         label &= IPV6_FLOWLABEL_MASK;
 
-        read_lock_bh(&ip6_sk_fl_lock);
-        for (sfl=np->ipv6_fl_list; sfl; sfl = sfl->next) {
+        rcu_read_lock_bh();
+        for_each_sk_fl_rcu(np, sfl) {
                 struct ip6_flowlabel *fl = sfl->fl;
                 if (fl->label == label) {
                         fl->lastuse = jiffies;
                         atomic_inc(&fl->users);
-                        read_unlock_bh(&ip6_sk_fl_lock);
+                        rcu_read_unlock_bh();
                         return fl;
                 }
         }
-        read_unlock_bh(&ip6_sk_fl_lock);
+        rcu_read_unlock_bh();
         return NULL;
 }
 
@@ -265,20 +270,21 @@ void fl6_free_socklist(struct sock *sk)
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct ipv6_fl_socklist *sfl;
 
-        if (!np->ipv6_fl_list)
+        if (!rcu_access_pointer(np->ipv6_fl_list))
                 return;
 
-        write_lock_bh(&ipv6_sk_fl_lock);
-        sfl = np->ipv6_fl_list;
-        np->ipv6_fl_list = NULL;
-        write_unlock_bh(&ipv6_sk_fl_lock);
+        spin_lock_bh(&ip6_sk_fl_lock);
+        while ((sfl = rcu_dereference_protected(np->ipv6_fl_list,
+                                                lockdep_is_held(&ip6_sk_fl_lock))) != NULL) {
+                np->ipv6_fl_list = sfl->next;
+                spin_unlock_bh(&ip6_sk_fl_lock);
 
-        while (sfl) {
-                struct ipv6_fl_socklist *next = sfl->next;
                 fl_release(sfl->fl);
-                kfree(sfl);
-                sfl = next;
+                kfree_rcu(sfl, rcu);
+
+                spin_lock_bh(&ip6_sk_fl_lock);
         }
+        spin_unlock_bh(&ip6_sk_fl_lock);
 }
 
 /* Service routines */
@@ -443,7 +449,7 @@ static int mem_check(struct sock *sk)
         if (room > FL_MAX_SIZE - FL_MAX_PER_SOCK)
                 return 0;
 
-        for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next)
+        for_each_sk_fl_rcu(np, sfl)
                 count++;
 
         if (room <= 0 ||
@@ -486,11 +492,11 @@ static bool ipv6_opt_cmp(struct ipv6_txoptions *o1, struct ipv6_txoptions *o2)
 static inline void fl_link(struct ipv6_pinfo *np, struct ipv6_fl_socklist *sfl,
                 struct ip6_flowlabel *fl)
 {
-        write_lock_bh(&ip6_sk_fl_lock);
+        spin_lock_bh(&ip6_sk_fl_lock);
         sfl->fl = fl;
         sfl->next = np->ipv6_fl_list;
-        np->ipv6_fl_list = sfl;
-        write_unlock_bh(&ip6_sk_fl_lock);
+        rcu_assign_pointer(np->ipv6_fl_list, sfl);
+        spin_unlock_bh(&ip6_sk_fl_lock);
 }
 
 int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
@@ -512,31 +518,33 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 
         switch (freq.flr_action) {
         case IPV6_FL_A_PUT:
-                write_lock_bh(&ip6_sk_fl_lock);
-                for (sflp = &np->ipv6_fl_list; (sfl=*sflp)!=NULL; sflp = &sfl->next) {
+                spin_lock_bh(&ip6_sk_fl_lock);
+                for (sflp = &np->ipv6_fl_list;
+                     (sfl = rcu_dereference(*sflp))!=NULL;
+                     sflp = &sfl->next) {
                         if (sfl->fl->label == freq.flr_label) {
                                 if (freq.flr_label == (np->flow_label&IPV6_FLOWLABEL_MASK))
                                         np->flow_label &= ~IPV6_FLOWLABEL_MASK;
-                                *sflp = sfl->next;
-                                write_unlock_bh(&ip6_sk_fl_lock);
+                                *sflp = rcu_dereference(sfl->next);
+                                spin_unlock_bh(&ip6_sk_fl_lock);
                                 fl_release(sfl->fl);
-                                kfree(sfl);
+                                kfree_rcu(sfl, rcu);
                                 return 0;
                         }
                 }
-                write_unlock_bh(&ip6_sk_fl_lock);
+                spin_unlock_bh(&ip6_sk_fl_lock);
                 return -ESRCH;
 
         case IPV6_FL_A_RENEW:
-                read_lock_bh(&ip6_sk_fl_lock);
-                for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
+                rcu_read_lock_bh();
+                for_each_sk_fl_rcu(np, sfl) {
                         if (sfl->fl->label == freq.flr_label) {
                                 err = fl6_renew(sfl->fl, freq.flr_linger, freq.flr_expires);
-                                read_unlock_bh(&ip6_sk_fl_lock);
+                                rcu_read_unlock_bh();
                                 return err;
                         }
                 }
-                read_unlock_bh(&ip6_sk_fl_lock);
+                rcu_read_unlock_bh();
 
                 if (freq.flr_share == IPV6_FL_S_NONE &&
                     ns_capable(net->user_ns, CAP_NET_ADMIN)) {
@@ -560,11 +568,11 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
 
                 if (freq.flr_label) {
                         err = -EEXIST;
-                        read_lock_bh(&ip6_sk_fl_lock);
-                        for (sfl = np->ipv6_fl_list; sfl; sfl = sfl->next) {
+                        rcu_read_lock_bh();
+                        for_each_sk_fl_rcu(np, sfl) {
                                 if (sfl->fl->label == freq.flr_label) {
                                         if (freq.flr_flags&IPV6_FL_F_EXCL) {
-                                                read_unlock_bh(&ip6_sk_fl_lock);
+                                                rcu_read_unlock_bh();
                                                 goto done;
                                         }
                                         fl1 = sfl->fl;
@@ -572,7 +580,7 @@ int ipv6_flowlabel_opt(struct sock *sk, char __user *optval, int optlen)
                                         break;
                                 }
                         }
-                        read_unlock_bh(&ip6_sk_fl_lock);
+                        rcu_read_unlock_bh();
 
                         if (fl1 == NULL)
                                 fl1 = fl_lookup(net, freq.flr_label);