Since 2.6.26 a new "midlevel private" ml_priv pointer has been

introduced in struct net_device. We use this pointer to omit the
linear walk through the can_rx_dev_list. A similar speedup has been
queued for 2.6.34 mainline but using the new netdev_rcu lists.

The mainline commit:
http://git.kernel.org/?p=linux/kernel/git/davem/net-next-2.6.git;a=commitdiff;h=20dd3850bcf860561496827b711fa10fecf6e787

git-svn-id: svn://svn.berlios.de//socketcan/trunk@1118 030b6a49-0b11-0410-94ab-b0dab22257f2

diff --git a/kernel/2.6/net/can/af_can.c b/kernel/2.6/net/can/af_can.c
index a96880456a1758294a3c324fec4ff1104c58f674..5f3713214cef245ec0a918381d3c64b3d41913f8 100644 (file)
--- a/kernel/2.6/net/can/af_can.c
+++ b/kernel/2.6/net/can/af_can.c
@@ -378,9 +378,28 @@ static struct dev_rcv_lists *find_dev_rcv_lists(struct net_device *dev)
        struct dev_rcv_lists *d = NULL;
        struct hlist_node *n;
 
+       /* find receive list for this device */
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
+       /*
+        * Since 2.6.26 a new "midlevel private" ml_priv pointer has been
+        * introduced in struct net_device. We use this pointer to omit the
+        * linear walk through the can_rx_dev_list. A similar speedup has been
+        * queued for 2.6.34 mainline but using the new netdev_rcu lists.
+        */
+
+       /* dev == NULL is the indicator for the 'all' filterlist */
+       if (!dev)
+               return &can_rx_alldev_list;
+
+       /* do not search in rcu list when we have a direct reference */
+       if (dev->ml_priv)
+               return (struct dev_rcv_lists *)dev->ml_priv;
+
+       /* fall back to standard behaviour */
+#endif
+
        /*
-        * find receive list for this device
-        *
         * The hlist_for_each_entry*() macros curse through the list
         * using the pointer variable n and set d to the containing
         * struct in each list iteration.  Therefore, after list
@@ -914,6 +933,9 @@ static int can_notifier(struct notifier_block *nb, unsigned long msg,
                d->dev = dev;
 
                spin_lock(&can_rcvlists_lock);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
+               dev->ml_priv = d;
+#endif
                hlist_add_head_rcu(&d->list, &can_rx_dev_list);
                spin_unlock(&can_rcvlists_lock);
 
@@ -927,8 +949,12 @@ static int can_notifier(struct notifier_block *nb, unsigned long msg,
                        if (d->entries) {
                                d->remove_on_zero_entries = 1;
                                d = NULL;
-                       } else
+                       } else {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,26)
+                               dev->ml_priv = NULL;
+#endif
                                hlist_del_rcu(&d->list);
+                       }
                } else
                        printk(KERN_ERR "can: notifier: receive list not "
                               "found for dev %s\n", dev->name);