1 files changed, 53 insertions, 44 deletions

diff --git a/net/decnet/dn_rules.c b/net/decnet/dn_rules.c
index f2c299dfe030..446faafe2065 100644
--- a/net/decnet/dn_rules.c
+++ b/net/decnet/dn_rules.c
@@ -27,6 +27,8 @@
 #include <linux/timer.h>
 #include <linux/spinlock.h>
 #include <linux/in_route.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
 #include <asm/atomic.h>
 #include <asm/uaccess.h>
 #include <net/neighbour.h>
@@ -39,7 +41,7 @@
 
 struct dn_fib_rule
 {
-        struct dn_fib_rule      *r_next;
+        struct hlist_node       r_hlist;
         atomic_t                r_clntref;
         u32                     r_preference;
         unsigned char           r_table;
@@ -58,6 +60,7 @@ struct dn_fib_rule
         int                     r_ifindex;
         char                    r_ifname[IFNAMSIZ];
         int                     r_dead;
+        struct rcu_head         rcu;
 };
 
 static struct dn_fib_rule default_rule = {
@@ -67,18 +70,17 @@ static struct dn_fib_rule default_rule = {
         .r_action =             RTN_UNICAST
 };
 
-static struct dn_fib_rule *dn_fib_rules = &default_rule;
-static DEFINE_RWLOCK(dn_fib_rules_lock);
-
+static struct hlist_head dn_fib_rules;
 
 int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 {
         struct rtattr **rta = arg;
         struct rtmsg *rtm = NLMSG_DATA(nlh);
-        struct dn_fib_rule *r, **rp;
+        struct dn_fib_rule *r;
+        struct hlist_node *node;
         int err = -ESRCH;
 
-        for(rp=&dn_fib_rules; (r=*rp) != NULL; rp = &r->r_next) {
+        hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
                 if ((!rta[RTA_SRC-1] || memcmp(RTA_DATA(rta[RTA_SRC-1]), &r->r_src, 2) == 0) &&
                         rtm->rtm_src_len == r->r_src_len &&
                         rtm->rtm_dst_len == r->r_dst_len &&
@@ -95,10 +97,8 @@ int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
                         if (r == &default_rule)
                                 break;
 
-                        write_lock_bh(&dn_fib_rules_lock);
-                        *rp = r->r_next;
+                        hlist_del_rcu(&r->r_hlist);
                         r->r_dead = 1;
-                        write_unlock_bh(&dn_fib_rules_lock);
                         dn_fib_rule_put(r);
                         err = 0;
                         break;
@@ -108,11 +108,17 @@ int dn_fib_rtm_delrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         return err;
 }
 
+static inline void dn_fib_rule_put_rcu(struct rcu_head *head)
+{
+        struct dn_fib_rule *r = container_of(head, struct dn_fib_rule, rcu);
+        kfree(r);
+}
+
 void dn_fib_rule_put(struct dn_fib_rule *r)
 {
         if (atomic_dec_and_test(&r->r_clntref)) {
                 if (r->r_dead)
-                        kfree(r);
+                        call_rcu(&r->rcu, dn_fib_rule_put_rcu);
                 else
                         printk(KERN_DEBUG "Attempt to free alive dn_fib_rule\n");
         }
@@ -123,7 +129,8 @@ int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
 {
         struct rtattr **rta = arg;
         struct rtmsg *rtm = NLMSG_DATA(nlh);
-        struct dn_fib_rule *r, *new_r, **rp;
+        struct dn_fib_rule *r, *new_r, *last = NULL;
+        struct hlist_node *node = NULL;
         unsigned char table_id;
 
         if (rtm->rtm_src_len > 16 || rtm->rtm_dst_len > 16)
@@ -149,6 +156,7 @@ int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
         if (!new_r)
                 return -ENOMEM;
         memset(new_r, 0, sizeof(*new_r));
+
         if (rta[RTA_SRC-1])
                 memcpy(&new_r->r_src, RTA_DATA(rta[RTA_SRC-1]), 2);
         if (rta[RTA_DST-1])
@@ -179,27 +187,26 @@ int dn_fib_rtm_newrule(struct sk_buff *skb, struct nlmsghdr *nlh, void *arg)
                 }
         }
 
-        rp = &dn_fib_rules;
+        r = container_of(dn_fib_rules.first, struct dn_fib_rule, r_hlist);
         if (!new_r->r_preference) {
-                r = dn_fib_rules;
-                if (r && (r = r->r_next) != NULL) {
-                        rp = &dn_fib_rules->r_next;
+                if (r && r->r_hlist.next != NULL) {
+                        r = container_of(r->r_hlist.next, struct dn_fib_rule, r_hlist);
                         if (r->r_preference)
                                 new_r->r_preference = r->r_preference - 1;
                 }
         }
 
-        while((r=*rp) != NULL) {
+        hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
                 if (r->r_preference > new_r->r_preference)
                         break;
-                rp = &r->r_next;
+                last = r;
         }
-
-        new_r->r_next = r;
         atomic_inc(&new_r->r_clntref);
-        write_lock_bh(&dn_fib_rules_lock);
-        *rp = new_r;
-        write_unlock_bh(&dn_fib_rules_lock);
+
+        if (last)
+                hlist_add_after_rcu(&last->r_hlist, &new_r->r_hlist);
+        else
+                hlist_add_before_rcu(&new_r->r_hlist, &r->r_hlist);
         return 0;
 }
 
@@ -210,10 +217,12 @@ int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
         struct dn_fib_table *tb;
         __le16 saddr = flp->fld_src;
         __le16 daddr = flp->fld_dst;
+        struct hlist_node *node;
         int err;
 
-        read_lock(&dn_fib_rules_lock);
-        for(r = dn_fib_rules; r; r = r->r_next) {
+        rcu_read_lock();
+
+        hlist_for_each_entry_rcu(r, node, &dn_fib_rules, r_hlist) {
                 if (((saddr^r->r_src) & r->r_srcmask) ||
                     ((daddr^r->r_dst) & r->r_dstmask) ||
 #ifdef CONFIG_DECNET_ROUTE_FWMARK
@@ -228,14 +237,14 @@ int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
                                 policy = r;
                                 break;
                         case RTN_UNREACHABLE:
-                                read_unlock(&dn_fib_rules_lock);
+                                rcu_read_unlock();
                                 return -ENETUNREACH;
                         default:
                         case RTN_BLACKHOLE:
-                                read_unlock(&dn_fib_rules_lock);
+                                rcu_read_unlock();
                                 return -EINVAL;
                         case RTN_PROHIBIT:
-                                read_unlock(&dn_fib_rules_lock);
+                                rcu_read_unlock();
                                 return -EACCES;
                 }
 
@@ -246,16 +255,16 @@ int dn_fib_lookup(const struct flowi *flp, struct dn_fib_res *res)
                         res->r = policy;
                         if (policy)
                                 atomic_inc(&policy->r_clntref);
-                        read_unlock(&dn_fib_rules_lock);
+                        rcu_read_unlock();
                         return 0;
                 }
                 if (err < 0 && err != -EAGAIN) {
-                        read_unlock(&dn_fib_rules_lock);
+                        rcu_read_unlock();
                         return err;
                 }
         }
 
-        read_unlock(&dn_fib_rules_lock);
+        rcu_read_unlock();
         return -ESRCH;
 }
 
@@ -297,27 +306,23 @@ __le16 dn_fib_rules_policy(__le16 saddr, struct dn_fib_res *res, unsigned *flags
 
 static void dn_fib_rules_detach(struct net_device *dev)
 {
+        struct hlist_node *node;
         struct dn_fib_rule *r;
 
-        for(r = dn_fib_rules; r; r = r->r_next) {
-                if (r->r_ifindex == dev->ifindex) {
-                        write_lock_bh(&dn_fib_rules_lock);
+        hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
+                if (r->r_ifindex == dev->ifindex)
                         r->r_ifindex = -1;
-                        write_unlock_bh(&dn_fib_rules_lock);
-                }
         }
 }
 
 static void dn_fib_rules_attach(struct net_device *dev)
 {
+        struct hlist_node *node;
         struct dn_fib_rule *r;
 
-        for(r = dn_fib_rules; r; r = r->r_next) {
-                if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0) {
-                        write_lock_bh(&dn_fib_rules_lock);
+        hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
+                if (r->r_ifindex == -1 && strcmp(dev->name, r->r_ifname) == 0)
                         r->r_ifindex = dev->ifindex;
-                        write_unlock_bh(&dn_fib_rules_lock);
-                }
         }
 }
 
@@ -387,18 +392,20 @@ rtattr_failure:
 
 int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 {
-        int idx;
+        int idx = 0;
         int s_idx = cb->args[0];
         struct dn_fib_rule *r;
+        struct hlist_node *node;
 
-        read_lock(&dn_fib_rules_lock);
-        for(r = dn_fib_rules, idx = 0; r; r = r->r_next, idx++) {
+        rcu_read_lock();
+        hlist_for_each_entry(r, node, &dn_fib_rules, r_hlist) {
                 if (idx < s_idx)
                         continue;
                 if (dn_fib_fill_rule(skb, r, cb, NLM_F_MULTI) < 0)
                         break;
+                idx++;
         }
-        read_unlock(&dn_fib_rules_lock);
+        rcu_read_unlock();
         cb->args[0] = idx;
 
         return skb->len;
@@ -406,6 +413,8 @@ int dn_fib_dump_rules(struct sk_buff *skb, struct netlink_callback *cb)
 
 void __init dn_fib_rules_init(void)
 {
+        INIT_HLIST_HEAD(&dn_fib_rules);
+        hlist_add_head(&default_rule.r_hlist, &dn_fib_rules);
         register_netdevice_notifier(&dn_fib_rules_notifier);
 }