[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>

1 files changed, 23 insertions, 11 deletions

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;
 }