1 files changed, 82 insertions, 29 deletions

diff --git a/net/llc/llc_sap.c b/net/llc/llc_sap.c
index 008de1fc42ca..ad6e6e1cf22f 100644
--- a/net/llc/llc_sap.c
+++ b/net/llc/llc_sap.c
@@ -297,6 +297,17 @@ static void llc_sap_rcv(struct llc_sap *sap, struct sk_buff *skb,
         llc_sap_state_process(sap, skb);
 }
 
+static inline bool llc_dgram_match(const struct llc_sap *sap,
+                                   const struct llc_addr *laddr,
+                                   const struct sock *sk)
+{
+     struct llc_sock *llc = llc_sk(sk);
+
+     return sk->sk_type == SOCK_DGRAM &&
+          llc->laddr.lsap == laddr->lsap &&
+          llc_mac_match(llc->laddr.mac, laddr->mac);
+}
+
 /**
  *      llc_lookup_dgram - Finds dgram socket for the local sap/mac
  *      @sap: SAP
@@ -309,25 +320,68 @@ static struct sock *llc_lookup_dgram(struct llc_sap *sap,
                                      const struct llc_addr *laddr)
 {
         struct sock *rc;
-        struct hlist_node *node;
-
-        read_lock_bh(&sap->sk_list.lock);
-        sk_for_each(rc, node, &sap->sk_list.list) {
-                struct llc_sock *llc = llc_sk(rc);
-
-                if (rc->sk_type == SOCK_DGRAM &&
-                    llc->laddr.lsap == laddr->lsap &&
-                    llc_mac_match(llc->laddr.mac, laddr->mac)) {
-                        sock_hold(rc);
+        struct hlist_nulls_node *node;
+        int slot = llc_sk_laddr_hashfn(sap, laddr);
+        struct hlist_nulls_head *laddr_hb = &sap->sk_laddr_hash[slot];
+
+        rcu_read_lock_bh();
+again:
+        sk_nulls_for_each_rcu(rc, node, laddr_hb) {
+                if (llc_dgram_match(sap, laddr, rc)) {
+                        /* Extra checks required by SLAB_DESTROY_BY_RCU */
+                        if (unlikely(!atomic_inc_not_zero(&rc->sk_refcnt)))
+                                goto again;
+                        if (unlikely(llc_sk(rc)->sap != sap ||
+                                     !llc_dgram_match(sap, laddr, rc))) {
+                                sock_put(rc);
+                                continue;
+                        }
                         goto found;
                 }
         }
         rc = NULL;
+        /*
+         * if the nulls value we got at the end of this lookup is
+         * not the expected one, we must restart lookup.
+         * We probably met an item that was moved to another chain.
+         */
+        if (unlikely(get_nulls_value(node) != slot))
+                goto again;
 found:
-        read_unlock_bh(&sap->sk_list.lock);
+        rcu_read_unlock_bh();
         return rc;
 }
 
+static inline bool llc_mcast_match(const struct llc_sap *sap,
+                                   const struct llc_addr *laddr,
+                                   const struct sk_buff *skb,
+                                   const struct sock *sk)
+{
+     struct llc_sock *llc = llc_sk(sk);
+
+     return sk->sk_type == SOCK_DGRAM &&
+          llc->laddr.lsap == laddr->lsap &&
+          llc->dev == skb->dev;
+}
+
+static void llc_do_mcast(struct llc_sap *sap, struct sk_buff *skb,
+                         struct sock **stack, int count)
+{
+        struct sk_buff *skb1;
+        int i;
+
+        for (i = 0; i < count; i++) {
+                skb1 = skb_clone(skb, GFP_ATOMIC);
+                if (!skb1) {
+                        sock_put(stack[i]);
+                        continue;
+                }
+
+                llc_sap_rcv(sap, skb1, stack[i]);
+                sock_put(stack[i]);
+        }
+}
+
 /**
  *      llc_sap_mcast - Deliver multicast PDU's to all matching datagram sockets.
  *      @sap: SAP
@@ -340,32 +394,31 @@ static void llc_sap_mcast(struct llc_sap *sap,
                           const struct llc_addr *laddr,
                           struct sk_buff *skb)
 {
-        struct sock *sk;
+        int i = 0, count = 256 / sizeof(struct sock *);
+        struct sock *sk, *stack[count];
         struct hlist_node *node;
+        struct llc_sock *llc;
+        struct hlist_head *dev_hb = llc_sk_dev_hash(sap, skb->dev->ifindex);
 
-        read_lock_bh(&sap->sk_list.lock);
-        sk_for_each(sk, node, &sap->sk_list.list) {
-                struct llc_sock *llc = llc_sk(sk);
-                struct sk_buff *skb1;
+        spin_lock_bh(&sap->sk_lock);
+        hlist_for_each_entry(llc, node, dev_hb, dev_hash_node) {
 
-                if (sk->sk_type != SOCK_DGRAM)
-                        continue;
+                sk = &llc->sk;
 
-                if (llc->laddr.lsap != laddr->lsap)
+                if (!llc_mcast_match(sap, laddr, skb, sk))
                         continue;
 
-                if (llc->dev != skb->dev)
-                        continue;
-
-                skb1 = skb_clone(skb, GFP_ATOMIC);
-                if (!skb1)
-                        break;
-
                 sock_hold(sk);
-                llc_sap_rcv(sap, skb1, sk);
-                sock_put(sk);
+                if (i < count)
+                        stack[i++] = sk;
+                else {
+                        llc_do_mcast(sap, skb, stack, i);
+                        i = 0;
+                }
         }
-        read_unlock_bh(&sap->sk_list.lock);
+        spin_unlock_bh(&sap->sk_lock);
+
+        llc_do_mcast(sap, skb, stack, i);
 }