[LLC]: Use refcounting with struct llc_sap

Signed-off-by: Jochen Friedrich <jochen@scram.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>

9 files changed, 56 insertions, 48 deletions

diff --git a/include/net/llc.h b/include/net/llc.h
index 8b8e2be289b1..93e5b443a9a7 100644
--- a/include/net/llc.h
+++ b/include/net/llc.h
@@ -17,6 +17,8 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 
+#include <asm/atomic.h>
+
 struct net_device;
 struct packet_type;
 struct sk_buff;
@@ -44,6 +46,7 @@ struct llc_sap {
         unsigned char    state;
         unsigned char    p_bit;
         unsigned char    f_bit;
+        atomic_t         refcnt;
         int              (*rcv_func)(struct sk_buff *skb,
                                      struct net_device *dev,
                                      struct packet_type *pt,
@@ -81,7 +84,18 @@ extern struct llc_sap *llc_sap_open(unsigned char lsap,
                                                struct net_device *dev,
                                                struct packet_type *pt,
                                                struct net_device *orig_dev));
-extern void llc_sap_close(struct llc_sap *sap);
+static inline void llc_sap_hold(struct llc_sap *sap)
+{
+        atomic_inc(&sap->refcnt);
+}
+
+static inline void llc_sap_put(struct llc_sap *sap)
+{
+        extern void llc_sap_close(struct llc_sap *sap);
+
+        if (atomic_dec_and_test(&sap->refcnt))
+                llc_sap_close(sap);
+}
 
 extern struct llc_sap *llc_sap_find(unsigned char sap_value);
 
diff --git a/include/net/llc_conn.h b/include/net/llc_conn.h
index 8a8ff4810135..b2889218c76a 100644
--- a/include/net/llc_conn.h
+++ b/include/net/llc_conn.h
@@ -115,5 +115,4 @@ extern void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk);
 
 extern u8 llc_data_accept_state(u8 state);
 extern void llc_build_offset_table(void);
-extern int llc_release_sockets(struct llc_sap *sap);
 #endif /* LLC_CONN_H */
diff --git a/net/802/p8022.c b/net/802/p8022.c
index b24817c63ca8..2530f35241cd 100644
--- a/net/802/p8022.c
+++ b/net/802/p8022.c
@@ -56,7 +56,7 @@ struct datalink_proto *register_8022_client(unsigned char type,
 
 void unregister_8022_client(struct datalink_proto *proto)
 {
-        llc_sap_close(proto->sap);
+        llc_sap_put(proto->sap);
         kfree(proto);
 }
 
diff --git a/net/802/psnap.c b/net/802/psnap.c
index ab80b1fab53c..4d638944d933 100644
--- a/net/802/psnap.c
+++ b/net/802/psnap.c
@@ -106,7 +106,7 @@ module_init(snap_init);
 
 static void __exit snap_exit(void)
 {
-        llc_sap_close(snap_sap);
+        llc_sap_put(snap_sap);
 }
 
 module_exit(snap_exit);
diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c
index ad9aad807aa8..a75b8f2aab19 100644
--- a/net/llc/af_llc.c
+++ b/net/llc/af_llc.c
@@ -21,6 +21,7 @@
  * See the GNU General Public License for more details.
  */
 #include <linux/config.h>
+#include <linux/compiler.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/rtnetlink.h>
@@ -188,10 +189,6 @@ static int llc_ui_release(struct socket *sock)
         if (!sock_flag(sk, SOCK_ZAPPED))
                 llc_sap_remove_socket(llc->sap, sk);
         release_sock(sk);
-        if (llc->sap && hlist_empty(&llc->sap->sk_list.list)) {
-                llc_release_sockets(llc->sap);
-                llc_sap_close(llc->sap);
-        }
         if (llc->dev)
                 dev_put(llc->dev);
         sock_put(sk);
@@ -220,6 +217,7 @@ static int llc_ui_autoport(void)
                                 llc_ui_sap_last_autoport = i + 2;
                                 goto out;
                         }
+                        llc_sap_put(sap);
                 }
                 llc_ui_sap_last_autoport = LLC_SAP_DYN_START;
                 tries++;
@@ -310,6 +308,7 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
                 rc = -EBUSY; /* some other network layer is using the sap */
                 if (!sap)
                         goto out;
+                llc_sap_hold(sap);
         } else {
                 struct llc_addr laddr, daddr;
                 struct sock *ask;
@@ -326,7 +325,7 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
                 ask = llc_lookup_established(sap, &daddr, &laddr);
                 if (ask) {
                         sock_put(ask);
-                        goto out;
+                        goto out_put;
                 }
         }
         llc->laddr.lsap = addr->sllc_sap;
@@ -336,6 +335,8 @@ static int llc_ui_bind(struct socket *sock, struct sockaddr *uaddr, int addrlen)
         llc_sap_add_socket(sap, sk);
         sock_reset_flag(sk, SOCK_ZAPPED);
         rc = 0;
+out_put:
+        llc_sap_put(sap);
 out:
         return rc;
 }
diff --git a/net/llc/llc_c_ac.c b/net/llc/llc_c_ac.c
index c1e75103189a..05236c2cbb9e 100644
--- a/net/llc/llc_c_ac.c
+++ b/net/llc/llc_c_ac.c
@@ -75,6 +75,7 @@ int llc_conn_ac_conn_ind(struct sock *sk, struct sk_buff *skb)
                 llc->dev = skb->dev;
                 ev->ind_prim = LLC_CONN_PRIM;
                 rc = 0;
+                llc_sap_put(sap);
         }
         return rc;
 }
diff --git a/net/llc/llc_conn.c b/net/llc/llc_conn.c
index 9f0e10e0978d..ab9e6d7e2875 100644
--- a/net/llc/llc_conn.c
+++ b/net/llc/llc_conn.c
@@ -633,6 +633,7 @@ static int llc_find_offset(int state, int ev_type)
  */
 void llc_sap_add_socket(struct llc_sap *sap, struct sock *sk)
 {
+        llc_sap_hold(sap);
         write_lock_bh(&sap->sk_list.lock);
         llc_sk(sk)->sap = sap;
         sk_add_node(sk, &sap->sk_list.list);
@@ -652,6 +653,7 @@ void llc_sap_remove_socket(struct llc_sap *sap, struct sock *sk)
         write_lock_bh(&sap->sk_list.lock);
         sk_del_node_init(sk);
         write_unlock_bh(&sap->sk_list.lock);
+        llc_sap_put(sap);
 }
 
 /**
@@ -731,32 +733,6 @@ static atomic_t llc_sock_nr;
 #endif
 
 /**
- *      llc_release_sockets - releases all sockets in a sap
- *      @sap: sap to release its sockets
- *
- *      Releases all connections of a sap. Returns 0 if all actions complete
- *      successfully, nonzero otherwise
- */
-int llc_release_sockets(struct llc_sap *sap)
-{
-        int rc = 0;
-        struct sock *sk;
-        struct hlist_node *node;
-
-        write_lock_bh(&sap->sk_list.lock);
-
-        sk_for_each(sk, node, &sap->sk_list.list) {
-                llc_sk(sk)->state = LLC_CONN_STATE_TEMP;
-
-                if (llc_send_disc(sk))
-                        rc = 1;
-        }
-
-        write_unlock_bh(&sap->sk_list.lock);
-        return rc;
-}
-
-/**
  *      llc_backlog_rcv - Processes rx frames and expired timers.
  *      @sk: LLC sock (p8022 connection)
  *      @skb: queued rx frame or event
diff --git a/net/llc/llc_core.c b/net/llc/llc_core.c
index 9727455bf0e7..9ccff1266b26 100644
--- a/net/llc/llc_core.c
+++ b/net/llc/llc_core.c
@@ -40,6 +40,7 @@ static struct llc_sap *llc_sap_alloc(void)
                 sap->state = LLC_SAP_STATE_ACTIVE;
                 memcpy(sap->laddr.mac, llc_station_mac_sa, ETH_ALEN);
                 rwlock_init(&sap->sk_list.lock);
+                atomic_set(&sap->refcnt, 1);
         }
         return sap;
 }
@@ -52,9 +53,7 @@ static struct llc_sap *llc_sap_alloc(void)
  */
 static void llc_add_sap(struct llc_sap *sap)
 {
-        write_lock_bh(&llc_sap_list_lock);
         list_add_tail(&sap->node, &llc_sap_list);
-        write_unlock_bh(&llc_sap_list_lock);
 }
 
 /**
@@ -70,11 +69,25 @@ static void llc_del_sap(struct llc_sap *sap)
         write_unlock_bh(&llc_sap_list_lock);
 }
 
+struct llc_sap *__llc_sap_find(unsigned char sap_value)
+{
+        struct llc_sap* sap;
+
+        list_for_each_entry(sap, &llc_sap_list, node)
+                if (sap->laddr.lsap == sap_value)
+                        goto out;
+        sap = NULL;
+out:
+        return sap;
+}
+
 /**
  *      llc_sap_find - searchs a SAP in station
  *      @sap_value: sap to be found
  *
  *      Searchs for a sap in the sap list of the LLC's station upon the sap ID.
+ *      If the sap is found it will be refcounted and the user will have to do
+ *      a llc_sap_put after use.
  *      Returns the sap or %NULL if not found.
  */
 struct llc_sap *llc_sap_find(unsigned char sap_value)
@@ -82,11 +95,9 @@ struct llc_sap *llc_sap_find(unsigned char sap_value)
         struct llc_sap* sap;
 
         read_lock_bh(&llc_sap_list_lock);
-        list_for_each_entry(sap, &llc_sap_list, node)
-                if (sap->laddr.lsap == sap_value)
-                        goto out;
-        sap = NULL;
-out:
+        sap = __llc_sap_find(sap_value);
+        if (sap)
+                llc_sap_hold(sap);
         read_unlock_bh(&llc_sap_list_lock);
         return sap;
 }
@@ -106,19 +117,20 @@ struct llc_sap *llc_sap_open(unsigned char lsap,
                                          struct packet_type *pt,
                                          struct net_device *orig_dev))
 {
-        struct llc_sap *sap = llc_sap_find(lsap);
+        struct llc_sap *sap = NULL;
 
-        if (sap) { /* SAP already exists */
-                sap = NULL;
+        write_lock_bh(&llc_sap_list_lock);
+        if (__llc_sap_find(lsap)) /* SAP already exists */
                 goto out;
-        }
         sap = llc_sap_alloc();
         if (!sap)
                 goto out;
         sap->laddr.lsap = lsap;
         sap->rcv_func   = func;
+        llc_sap_hold(sap);
         llc_add_sap(sap);
 out:
+        write_unlock_bh(&llc_sap_list_lock);
         return sap;
 }
 
diff --git a/net/llc/llc_input.c b/net/llc/llc_input.c
index 60c1acac7c97..789eec426451 100644
--- a/net/llc/llc_input.c
+++ b/net/llc/llc_input.c
@@ -166,17 +166,22 @@ int llc_rcv(struct sk_buff *skb, struct net_device *dev,
          */
         if (sap->rcv_func) {
                 sap->rcv_func(skb, dev, pt, orig_dev);
-                goto out;
+                goto out_put;
         }
         dest = llc_pdu_type(skb);
         if (unlikely(!dest || !llc_type_handlers[dest - 1]))
-                goto drop;
+                goto drop_put;
         llc_type_handlers[dest - 1](sap, skb);
+out_put:
+        llc_sap_put(sap);
 out:
         return 0;
 drop:
         kfree_skb(skb);
         goto out;
+drop_put:
+        kfree_skb(skb);
+        goto out_put;
 handle_station:
         if (!llc_station_handler)
                 goto drop;