[INET]: Use list_head-s in inetpeer.c

The inetpeer.c tracks the LRU list of inet_perr-s, but makes
it by hands. Use the list_head-s for this.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 16 insertions, 28 deletions

diff --git a/include/net/inetpeer.h b/include/net/inetpeer.h
index aa10a8178e70..ad8404b56113 100644
--- a/include/net/inetpeer.h
+++ b/include/net/inetpeer.h
@@ -22,7 +22,7 @@ struct inet_peer
         __be32                  v4daddr;        /* peer's address */
         __u16                   avl_height;
         __u16                   ip_id_count;    /* IP ID for the next packet */
-        struct inet_peer        *unused_next, **unused_prevp;
+        struct list_head        unused;
         __u32                   dtime;          /* the time of last use of not
                                                  * referenced entries */
         atomic_t                refcnt;
diff --git a/net/ipv4/inetpeer.c b/net/ipv4/inetpeer.c
index 771031dfbd0f..af995198f643 100644
--- a/net/ipv4/inetpeer.c
+++ b/net/ipv4/inetpeer.c
@@ -61,7 +61,7 @@
  *  4.  Global variable peer_total is modified under the pool lock.
  *  5.  struct inet_peer fields modification:
  *              avl_left, avl_right, avl_parent, avl_height: pool lock
- *              unused_next, unused_prevp: unused node list lock
+ *              unused: unused node list lock
  *              refcnt: atomically against modifications on other CPU;
  *                 usually under some other lock to prevent node disappearing
  *              dtime: unused node list lock
@@ -94,8 +94,7 @@ int inet_peer_maxttl __read_mostly = 10 * 60 * HZ;	/* usual time to live: 10 min
 int inet_peer_gc_mintime __read_mostly = 10 * HZ;
 int inet_peer_gc_maxtime __read_mostly = 120 * HZ;
 
-static struct inet_peer *inet_peer_unused_head;
-static struct inet_peer **inet_peer_unused_tailp = &inet_peer_unused_head;
+static LIST_HEAD(unused_peers);
 static DEFINE_SPINLOCK(inet_peer_unused_lock);
 
 static void peer_check_expire(unsigned long dummy);
@@ -138,15 +137,7 @@ void __init inet_initpeers(void)
 static void unlink_from_unused(struct inet_peer *p)
 {
         spin_lock_bh(&inet_peer_unused_lock);
-        if (p->unused_prevp != NULL) {
-                /* On unused list. */
-                *p->unused_prevp = p->unused_next;
-                if (p->unused_next != NULL)
-                        p->unused_next->unused_prevp = p->unused_prevp;
-                else
-                        inet_peer_unused_tailp = p->unused_prevp;
-                p->unused_prevp = NULL; /* mark it as removed */
-        }
+        list_del_init(&p->unused);
         spin_unlock_bh(&inet_peer_unused_lock);
 }
 
@@ -337,24 +328,24 @@ static void unlink_from_pool(struct inet_peer *p)
 /* May be called with local BH enabled. */
 static int cleanup_once(unsigned long ttl)
 {
-        struct inet_peer *p;
+        struct inet_peer *p = NULL;
 
         /* Remove the first entry from the list of unused nodes. */
         spin_lock_bh(&inet_peer_unused_lock);
-        p = inet_peer_unused_head;
-        if (p != NULL) {
-                __u32 delta = (__u32)jiffies - p->dtime;
+        if (!list_empty(&unused_peers)) {
+                __u32 delta;
+
+                p = list_first_entry(&unused_peers, struct inet_peer, unused);
+                delta = (__u32)jiffies - p->dtime;
+
                 if (delta < ttl) {
                         /* Do not prune fresh entries. */
                         spin_unlock_bh(&inet_peer_unused_lock);
                         return -1;
                 }
-                inet_peer_unused_head = p->unused_next;
-                if (p->unused_next != NULL)
-                        p->unused_next->unused_prevp = p->unused_prevp;
-                else
-                        inet_peer_unused_tailp = p->unused_prevp;
-                p->unused_prevp = NULL; /* mark as not on the list */
+
+                list_del_init(&p->unused);
+
                 /* Grab an extra reference to prevent node disappearing
                  * before unlink_from_pool() call. */
                 atomic_inc(&p->refcnt);
@@ -412,7 +403,7 @@ struct inet_peer *inet_getpeer(__be32 daddr, int create)
 
         /* Link the node. */
         link_to_pool(n);
-        n->unused_prevp = NULL; /* not on the list */
+        INIT_LIST_HEAD(&n->unused);
         peer_total++;
         write_unlock_bh(&peer_pool_lock);
 
@@ -467,10 +458,7 @@ void inet_putpeer(struct inet_peer *p)
 {
         spin_lock_bh(&inet_peer_unused_lock);
         if (atomic_dec_and_test(&p->refcnt)) {
-                p->unused_prevp = inet_peer_unused_tailp;
-                p->unused_next = NULL;
-                *inet_peer_unused_tailp = p;
-                inet_peer_unused_tailp = &p->unused_next;
+                list_add_tail(&p->unused, &unused_peers);
                 p->dtime = (__u32)jiffies;
         }
         spin_unlock_bh(&inet_peer_unused_lock);