llc: convert llc_sap_list to RCU

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 18 insertions, 39 deletions

diff --git a/net/llc/llc_core.c b/net/llc/llc_core.c
index 0c9ef8bc7655..78167e81dfeb 100644
--- a/net/llc/llc_core.c
+++ b/net/llc/llc_core.c
@@ -23,7 +23,7 @@
 #include <net/llc.h>
 
 LIST_HEAD(llc_sap_list);
-DEFINE_RWLOCK(llc_sap_list_lock);
+DEFINE_SPINLOCK(llc_sap_list_lock);
 
 /**
  *      llc_sap_alloc - allocates and initializes sap.
@@ -46,30 +46,6 @@ static struct llc_sap *llc_sap_alloc(void)
         return sap;
 }
 
-/**
- *      llc_add_sap - add sap to station list
- *      @sap: Address of the sap
- *
- *      Adds a sap to the LLC's station sap list.
- */
-static void llc_add_sap(struct llc_sap *sap)
-{
-        list_add_tail(&sap->node, &llc_sap_list);
-}
-
-/**
- *      llc_del_sap - del sap from station list
- *      @sap: Address of the sap
- *
- *      Removes a sap to the LLC's station sap list.
- */
-static void llc_del_sap(struct llc_sap *sap)
-{
-        write_lock_bh(&llc_sap_list_lock);
-        list_del(&sap->node);
-        write_unlock_bh(&llc_sap_list_lock);
-}
-
 static struct llc_sap *__llc_sap_find(unsigned char sap_value)
 {
         struct llc_sap* sap;
@@ -93,13 +69,13 @@ out:
  */
 struct llc_sap *llc_sap_find(unsigned char sap_value)
 {
-        struct llc_sap* sap;
+        struct llc_sap *sap;
 
-        read_lock_bh(&llc_sap_list_lock);
+        rcu_read_lock_bh();
         sap = __llc_sap_find(sap_value);
         if (sap)
                 llc_sap_hold(sap);
-        read_unlock_bh(&llc_sap_list_lock);
+        rcu_read_unlock_bh();
         return sap;
 }
 
@@ -120,7 +96,7 @@ struct llc_sap *llc_sap_open(unsigned char lsap,
 {
         struct llc_sap *sap = NULL;
 
-        write_lock_bh(&llc_sap_list_lock);
+        spin_lock_bh(&llc_sap_list_lock);
         if (__llc_sap_find(lsap)) /* SAP already exists */
                 goto out;
         sap = llc_sap_alloc();
@@ -128,9 +104,9 @@ struct llc_sap *llc_sap_open(unsigned char lsap,
                 goto out;
         sap->laddr.lsap = lsap;
         sap->rcv_func   = func;
-        llc_add_sap(sap);
+        list_add_tail_rcu(&sap->node, &llc_sap_list);
 out:
-        write_unlock_bh(&llc_sap_list_lock);
+        spin_unlock_bh(&llc_sap_list_lock);
         return sap;
 }
 
@@ -146,7 +122,13 @@ out:
 void llc_sap_close(struct llc_sap *sap)
 {
         WARN_ON(sap->sk_count);
-        llc_del_sap(sap);
+
+        spin_lock_bh(&llc_sap_list_lock);
+        list_del_rcu(&sap->node);
+        spin_unlock_bh(&llc_sap_list_lock);
+
+        synchronize_rcu();
+
         kfree(sap);
 }
 
diff --git a/net/llc/llc_proc.c b/net/llc/llc_proc.c
index 09dec6307206..7af1ff2d1f19 100644
--- a/net/llc/llc_proc.c
+++ b/net/llc/llc_proc.c
@@ -32,14 +32,11 @@ static void llc_ui_format_mac(struct seq_file *seq, u8 *addr)
 
 static struct sock *llc_get_sk_idx(loff_t pos)
 {
-        struct list_head *sap_entry;
         struct llc_sap *sap;
         struct sock *sk = NULL;
         int i;
 
-        list_for_each(sap_entry, &llc_sap_list) {
-                sap = list_entry(sap_entry, struct llc_sap, node);
-
+        list_for_each_entry_rcu(sap, &llc_sap_list, node) {
                 spin_lock_bh(&sap->sk_lock);
                 for (i = 0; i < LLC_SK_LADDR_HASH_ENTRIES; i++) {
                         struct hlist_nulls_head *head = &sap->sk_laddr_hash[i];
@@ -62,7 +59,7 @@ static void *llc_seq_start(struct seq_file *seq, loff_t *pos)
 {
         loff_t l = *pos;
 
-        read_lock_bh(&llc_sap_list_lock);
+        rcu_read_lock_bh();
         return l ? llc_get_sk_idx(--l) : SEQ_START_TOKEN;
 }
 
@@ -102,7 +99,7 @@ static void *llc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
         if (sk)
                 goto out;
         spin_unlock_bh(&sap->sk_lock);
-        list_for_each_entry_continue(sap, &llc_sap_list, node) {
+        list_for_each_entry_continue_rcu(sap, &llc_sap_list, node) {
                 spin_lock_bh(&sap->sk_lock);
                 sk = laddr_hash_next(sap, -1);
                 if (sk)
@@ -122,7 +119,7 @@ static void llc_seq_stop(struct seq_file *seq, void *v)
 
                 spin_unlock_bh(&sap->sk_lock);
         }
-        read_unlock_bh(&llc_sap_list_lock);
+        rcu_read_unlock_bh();
 }
 
 static int llc_seq_socket_show(struct seq_file *seq, void *v)