[VLAN]: Avoid a 4-order allocation.

This patch splits the vlan_group struct into a multi-allocated struct. On
x86_64, the size of the original struct is a little more than 32KB, causing
a 4-order allocation, which is prune to problems caused by buddy-system
external fragmentation conditions.

I couldn't just use vmalloc() because vfree() cannot be called in the
softirq context of the RCU callback.

Signed-off-by: Dan Aloni <[e-mail]>
Acked-by: Jeff Garzik <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/8139cp.c

···
 	spin_lock_irqsave(&cp->lock, flags);
 	cp->cpcmd &= ~RxVlanOn;
 	cpw16(CpCmd, cp->cpcmd);
-	if (cp->vlgrp)
-		cp->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(cp->vlgrp, vid, NULL);
 	spin_unlock_irqrestore(&cp->lock, flags);
 }
 #endif /* CP_VLAN_TAG_USED */

drivers/net/acenic.c

···
 
 	local_irq_save(flags);
 	ace_mask_irq(dev);
-
-	if (ap->vlgrp)
-		ap->vlgrp->vlan_devices[vid] = NULL;
-
+	vlan_group_set_device(ap->vlgrp, vid, NULL);
 	ace_unmask_irq(dev);
 	local_irq_restore(flags);
 }

drivers/net/amd8111e.c

···
 {
 	struct amd8111e_priv *lp = netdev_priv(dev);
 	spin_lock_irq(&lp->lock);
-	if (lp->vlgrp)
-		lp->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(lp->vlgrp, vid, NULL);
 	spin_unlock_irq(&lp->lock);
 }
 #endif

drivers/net/atl1/atl1_main.c

···
 
 	spin_lock_irqsave(&adapter->lock, flags);
 	/* atl1_irq_disable(adapter); */
-	if (adapter->vlgrp)
-		adapter->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(adapter->vlgrp, vid, NULL);
 	/* atl1_irq_enable(adapter); */
 	spin_unlock_irqrestore(&adapter->lock, flags);
 	/* We don't do Vlan filtering */
···
 	if (adapter->vlgrp) {
 		u16 vid;
 		for (vid = 0; vid < VLAN_GROUP_ARRAY_LEN; vid++) {
-			if (!adapter->vlgrp->vlan_devices[vid])
+			if (!vlan_group_get_device(adapter->vlgrp, vid))
 				continue;
 			atl1_vlan_rx_add_vid(adapter->netdev, vid);
 		}

drivers/net/bnx2.c

···
 	struct bnx2 *bp = netdev_priv(dev);
 
 	bnx2_netif_stop(bp);
-
-	if (bp->vlgrp)
-		bp->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(bp->vlgrp, vid, NULL);
 	bnx2_set_rx_mode(dev);
 
 	bnx2_netif_start(bp);

drivers/net/bonding/bond_main.c

···
 			/* Save and then restore vlan_dev in the grp array,
 			 * since the slave's driver might clear it.
 			 */
-			vlan_dev = bond->vlgrp->vlan_devices[vid];
+			vlan_dev = vlan_group_get_device(bond->vlgrp, vid);
 			slave_dev->vlan_rx_kill_vid(slave_dev, vid);
-			bond->vlgrp->vlan_devices[vid] = vlan_dev;
+			vlan_group_set_device(bond->vlgrp, vid, vlan_dev);
 		}
 	}
 
···
 		/* Save and then restore vlan_dev in the grp array,
 		 * since the slave's driver might clear it.
 		 */
-		vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
+		vlan_dev = vlan_group_get_device(bond->vlgrp, vlan->vlan_id);
 		slave_dev->vlan_rx_kill_vid(slave_dev, vlan->vlan_id);
-		bond->vlgrp->vlan_devices[vlan->vlan_id] = vlan_dev;
+		vlan_group_set_device(bond->vlgrp, vlan->vlan_id, vlan_dev);
 	}
 
 unreg:
···
 		vlan_id = 0;
 		list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
 					 vlan_list) {
-			vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
+			vlan_dev = vlan_group_get_device(bond->vlgrp, vlan->vlan_id);
 			if (vlan_dev == rt->u.dst.dev) {
 				vlan_id = vlan->vlan_id;
 				dprintk("basa: vlan match on %s %d\n",
···
 	}
 
 	list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
-		vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
+		vlan_dev = vlan_group_get_device(bond->vlgrp, vlan->vlan_id);
 		if (vlan->vlan_ip) {
 			bond_arp_send(slave->dev, ARPOP_REPLY, vlan->vlan_ip,
 				      vlan->vlan_ip, vlan->vlan_id);
···
 
 		list_for_each_entry_safe(vlan, vlan_next, &bond->vlan_list,
 					 vlan_list) {
-			vlan_dev = bond->vlgrp->vlan_devices[vlan->vlan_id];
+			vlan_dev = vlan_group_get_device(bond->vlgrp, vlan->vlan_id);
 			if (vlan_dev == event_dev) {
 				switch (event) {
 				case NETDEV_UP:

drivers/net/chelsio/cxgb2.c

···
 	struct adapter *adapter = dev->priv;
 
 	spin_lock_irq(&adapter->async_lock);
-	if (adapter->vlan_grp)
-		adapter->vlan_grp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(adapter->vlan_grp, vid, NULL);
 	spin_unlock_irq(&adapter->async_lock);
 }
 #endif

drivers/net/cxgb3/cxgb3_offload.c

···
 	int i;
 
 	for_each_port(adapter, i) {
-		const struct vlan_group *grp;
+		struct vlan_group *grp;
 		struct net_device *dev = adapter->port[i];
 		const struct port_info *p = netdev_priv(dev);
 
 		if (!memcmp(dev->dev_addr, mac, ETH_ALEN)) {
 			if (vlan && vlan != VLAN_VID_MASK) {
 				grp = p->vlan_grp;
-				dev = grp ? grp->vlan_devices[vlan] : NULL;
+				dev = NULL;
+				if (grp)
+					dev = vlan_group_get_device(grp, vlan);
 			} else
 				while (dev->master)
 					dev = dev->master;

drivers/net/e1000/e1000_main.c

···
 	uint16_t vid = adapter->hw.mng_cookie.vlan_id;
 	uint16_t old_vid = adapter->mng_vlan_id;
 	if (adapter->vlgrp) {
-		if (!adapter->vlgrp->vlan_devices[vid]) {
+		if (!vlan_group_get_device(adapter->vlgrp, vid)) {
 			if (adapter->hw.mng_cookie.status &
 				E1000_MNG_DHCP_COOKIE_STATUS_VLAN_SUPPORT) {
 				e1000_vlan_rx_add_vid(netdev, vid);
···
 
 			if ((old_vid != (uint16_t)E1000_MNG_VLAN_NONE) &&
 					(vid != old_vid) &&
-					!adapter->vlgrp->vlan_devices[old_vid])
+			    !vlan_group_get_device(adapter->vlgrp, old_vid))
 				e1000_vlan_rx_kill_vid(netdev, old_vid);
 		} else
 			adapter->mng_vlan_id = vid;
···
 	if ((adapter->hw.mng_cookie.status &
 			  E1000_MNG_DHCP_COOKIE_STATUS_VLAN_SUPPORT) &&
 	     !(adapter->vlgrp &&
-			  adapter->vlgrp->vlan_devices[adapter->mng_vlan_id])) {
+	       vlan_group_get_device(adapter->vlgrp, adapter->mng_vlan_id))) {
 		e1000_vlan_rx_kill_vid(netdev, adapter->mng_vlan_id);
 	}
 
···
 	uint32_t vfta, index;
 
 	e1000_irq_disable(adapter);
-
-	if (adapter->vlgrp)
-		adapter->vlgrp->vlan_devices[vid] = NULL;
-
+	vlan_group_set_device(adapter->vlgrp, vid, NULL);
 	e1000_irq_enable(adapter);
 
 	if ((adapter->hw.mng_cookie.status &
···
 	if (adapter->vlgrp) {
 		uint16_t vid;
 		for (vid = 0; vid < VLAN_GROUP_ARRAY_LEN; vid++) {
-			if (!adapter->vlgrp->vlan_devices[vid])
+			if (!vlan_group_get_device(adapter->vlgrp, vid))
 				continue;
 			e1000_vlan_rx_add_vid(adapter->netdev, vid);
 		}

drivers/net/ehea/ehea_main.c

···
 	int index;
 	u64 hret;
 
-	if (port->vgrp)
-		port->vgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(port->vgrp, vid, NULL);
 
 	cb1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!cb1) {

drivers/net/gianfar.c

···
 
 	spin_lock_irqsave(&priv->rxlock, flags);
 
-	if (priv->vlgrp)
-		priv->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(priv->vgrp, vid, NULL);
 
 	spin_unlock_irqrestore(&priv->rxlock, flags);
 }

drivers/net/ixgb/ixgb_main.c

···
 
 	ixgb_irq_disable(adapter);
 
-	if(adapter->vlgrp)
-		adapter->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(adapter->vlgrp, vid, NULL);
 
 	ixgb_irq_enable(adapter);
 
···
 	if(adapter->vlgrp) {
 		uint16_t vid;
 		for(vid = 0; vid < VLAN_GROUP_ARRAY_LEN; vid++) {
-			if(!adapter->vlgrp->vlan_devices[vid])
+			if(!vlan_group_get_device(adapter->vlgrp, vid))
 				continue;
 			ixgb_vlan_rx_add_vid(adapter->netdev, vid);
 		}

drivers/net/ns83820.c

···
 
 	spin_lock_irq(&dev->misc_lock);
 	spin_lock(&dev->tx_lock);
-	if (dev->vlgrp)
-		dev->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(dev->vlgrp, vid, NULL);
 	spin_unlock(&dev->tx_lock);
 	spin_unlock_irq(&dev->misc_lock);
 }

drivers/net/r8169.c

···
 	unsigned long flags;
 
 	spin_lock_irqsave(&tp->lock, flags);
-	if (tp->vlgrp)
-		tp->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(tp->vlgrp, vid, NULL);
 	spin_unlock_irqrestore(&tp->lock, flags);
 }
 

drivers/net/s2io.c

···
 	unsigned long flags;
 
 	spin_lock_irqsave(&nic->tx_lock, flags);
-	if (nic->vlgrp)
-		nic->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(nic->vlgrp, vid, NULL);
 	spin_unlock_irqrestore(&nic->tx_lock, flags);
 }
 

drivers/net/sky2.c

···
 
 	sky2_write32(hw, SK_REG(port, RX_GMF_CTRL_T), RX_VLAN_STRIP_OFF);
 	sky2_write32(hw, SK_REG(port, TX_GMF_CTRL_T), TX_VLAN_TAG_OFF);
-	if (sky2->vlgrp)
-		sky2->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(sky2->vlgrp, vid, NULL);
 
 	netif_tx_unlock_bh(dev);
 }

drivers/net/starfire.c

···
 	spin_lock(&np->lock);
 	if (debug > 1)
 		printk("%s: removing vlanid %d from vlan filter\n", dev->name, vid);
-	if (np->vlgrp)
-		np->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(np->vlgrp, vid, NULL);
 	set_rx_mode(dev);
 	spin_unlock(&np->lock);
 }
···
 		int vlan_count = 0;
 		void __iomem *filter_addr = ioaddr + HashTable + 8;
 		for (i = 0; i < VLAN_VID_MASK; i++) {
-			if (np->vlgrp->vlan_devices[i]) {
+			if (vlan_group_get_device(np->vlgrp, i)) {
 				if (vlan_count >= 32)
 					break;
 				writew(cpu_to_be16(i), filter_addr);

drivers/net/tg3.c

···
 		tg3_netif_stop(tp);
 
 	tg3_full_lock(tp, 0);
-	if (tp->vlgrp)
-		tp->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(tp->vlgrp, vid, NULL);
 	tg3_full_unlock(tp);
 
 	if (netif_running(dev))

drivers/net/typhoon.c

···
 {
 	struct typhoon *tp = netdev_priv(dev);
 	spin_lock_bh(&tp->state_lock);
-	if(tp->vlgrp)
-		tp->vlgrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(tp->vlgrp, vid, NULL);
 	spin_unlock_bh(&tp->state_lock);
 }
 

drivers/s390/net/qeth_main.c

···
 		return rc;
 
 	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++){
-		if (vg->vlan_devices[i] == dev){
+		if (vlan_group_get_device(vg, i) == dev){
 			rc = QETH_VLAN_CARD;
 			break;
 		}
···
 	QETH_DBF_TEXT(trace, 4, "frvaddr4");
 
 	rcu_read_lock();
-	in_dev = __in_dev_get_rcu(card->vlangrp->vlan_devices[vid]);
+	in_dev = __in_dev_get_rcu(vlan_group_get_device(card->vlangrp, vid));
 	if (!in_dev)
 		goto out;
 	for (ifa = in_dev->ifa_list; ifa; ifa = ifa->ifa_next) {
···
 
 	QETH_DBF_TEXT(trace, 4, "frvaddr6");
 
-	in6_dev = in6_dev_get(card->vlangrp->vlan_devices[vid]);
+	in6_dev = in6_dev_get(vlan_group_get_device(card->vlangrp, vid));
 	if (!in6_dev)
 		return;
 	for (ifa = in6_dev->addr_list; ifa; ifa = ifa->lst_next){
···
 	if (!card->vlangrp)
 		return;
 	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
-		if (card->vlangrp->vlan_devices[i] == NULL)
+		if (vlan_group_get_device(card->vlangrp, i) == NULL)
 			continue;
 		if (clear)
 			qeth_layer2_send_setdelvlan(card, i, IPA_CMD_DELVLAN);
···
 	spin_lock_irqsave(&card->vlanlock, flags);
 	/* unregister IP addresses of vlan device */
 	qeth_free_vlan_addresses(card, vid);
-	if (card->vlangrp)
-		card->vlangrp->vlan_devices[vid] = NULL;
+	vlan_group_set_device(card->vlangrp, vid, NULL);
 	spin_unlock_irqrestore(&card->vlanlock, flags);
 	if (card->options.layer2)
 		qeth_layer2_send_setdelvlan(card, vid, IPA_CMD_DELVLAN);
···
 
 	vg = card->vlangrp;
 	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
-		if (vg->vlan_devices[i] == NULL ||
-		    !(vg->vlan_devices[i]->flags & IFF_UP))
+		struct net_device *netdev = vlan_group_get_device(vg, i);
+		if (netdev == NULL ||
+		    !(netdev->flags & IFF_UP))
 			continue;
-		in_dev = in_dev_get(vg->vlan_devices[i]);
+		in_dev = in_dev_get(netdev);
 		if (!in_dev)
 			continue;
 		read_lock(&in_dev->mc_list_lock);
···
 
 	vg = card->vlangrp;
 	for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
-		if (vg->vlan_devices[i] == NULL ||
-		    !(vg->vlan_devices[i]->flags & IFF_UP))
+		struct net_device *netdev = vlan_group_get_device(vg, i);
+		if (netdev == NULL ||
+		    !(netdev->flags & IFF_UP))
 			continue;
-		in_dev = in6_dev_get(vg->vlan_devices[i]);
+		in_dev = in6_dev_get(netdev);
 		if (!in_dev)
 			continue;
 		read_lock(&in_dev->lock);

include/linux/if_vlan.h

···
  * depends on completely exhausting the VLAN identifier space.  Thus
  * it gives constant time look-up, but in many cases it wastes memory.
  */
-#define VLAN_GROUP_ARRAY_LEN 4096
+#define VLAN_GROUP_ARRAY_LEN          4096
+#define VLAN_GROUP_ARRAY_SPLIT_PARTS  8
+#define VLAN_GROUP_ARRAY_PART_LEN     (VLAN_GROUP_ARRAY_LEN/VLAN_GROUP_ARRAY_SPLIT_PARTS)
 
 struct vlan_group {
 	int real_dev_ifindex; /* The ifindex of the ethernet(like) device the vlan is attached to. */
 	struct hlist_node	hlist;	/* linked list */
-	struct net_device *vlan_devices[VLAN_GROUP_ARRAY_LEN];
+	struct net_device **vlan_devices_arrays[VLAN_GROUP_ARRAY_SPLIT_PARTS];
 	struct rcu_head		rcu;
 };
+
+static inline struct net_device *vlan_group_get_device(struct vlan_group *vg, int vlan_id)
+{
+	struct net_device **array;
+	array = vg->vlan_devices_arrays[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
+	return array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN];
+}
+
+static inline void vlan_group_set_device(struct vlan_group *vg, int vlan_id,
+					 struct net_device *dev)
+{
+	struct net_device **array;
+	if (!vg)
+		return;
+	array = vg->vlan_devices_arrays[vlan_id / VLAN_GROUP_ARRAY_PART_LEN];
+	array[vlan_id % VLAN_GROUP_ARRAY_PART_LEN] = dev;
+}
 
 struct vlan_priority_tci_mapping {
 	unsigned long priority;
···
 		return NET_RX_DROP;
 	}
 
-	skb->dev = grp->vlan_devices[vlan_tag & VLAN_VID_MASK];
+	skb->dev = vlan_group_get_device(grp, vlan_tag & VLAN_VID_MASK);
 	if (skb->dev == NULL) {
 		dev_kfree_skb_any(skb);
 

net/8021q/vlan.c

···
 	struct vlan_group *grp = __vlan_find_group(real_dev->ifindex);
 
 	if (grp)
-		return grp->vlan_devices[VID];
+		return vlan_group_get_device(grp, VID);
 
 	return NULL;
 }
 
+static void vlan_group_free(struct vlan_group *grp)
+{
+	int i;
+
+	for (i=0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++)
+		kfree(grp->vlan_devices_arrays[i]);
+	kfree(grp);
+}
+
 static void vlan_rcu_free(struct rcu_head *rcu)
 {
-	kfree(container_of(rcu, struct vlan_group, rcu));
+	vlan_group_free(container_of(rcu, struct vlan_group, rcu));
 }
 
 
···
 	ret = 0;
 
 	if (grp) {
-		dev = grp->vlan_devices[vlan_id];
+		dev = vlan_group_get_device(grp, vlan_id);
 		if (dev) {
 			/* Remove proc entry */
 			vlan_proc_rem_dev(dev);
···
 				real_dev->vlan_rx_kill_vid(real_dev, vlan_id);
 			}
 
-			grp->vlan_devices[vlan_id] = NULL;
+			vlan_group_set_device(grp, vlan_id, NULL);
 			synchronize_net();
 
 
···
 			 * group.
 			 */
 			for (i = 0; i < VLAN_VID_MASK; i++)
-				if (grp->vlan_devices[i])
+				if (vlan_group_get_device(grp, i))
 					break;
 
 			if (i == VLAN_VID_MASK) {
···
 	struct net_device *new_dev;
 	struct net_device *real_dev; /* the ethernet device */
 	char name[IFNAMSIZ];
+	int i;
 
 #ifdef VLAN_DEBUG
 	printk(VLAN_DBG "%s: if_name -:%s:-	vid: %i\n",
···
 		if (!grp)
 			goto out_free_unregister;
 
+		for (i=0; i < VLAN_GROUP_ARRAY_SPLIT_PARTS; i++) {
+			grp->vlan_devices_arrays[i] = kzalloc(
+				sizeof(struct net_device *)*VLAN_GROUP_ARRAY_PART_LEN,
+				GFP_KERNEL);
+
+			if (!grp->vlan_devices_arrays[i])
+				goto out_free_arrays;
+		}
+
 		/* printk(KERN_ALERT "VLAN REGISTER:  Allocated new group.\n"); */
 		grp->real_dev_ifindex = real_dev->ifindex;
 
···
 			real_dev->vlan_rx_register(real_dev, grp);
 	}
 
-	grp->vlan_devices[VLAN_ID] = new_dev;
+	vlan_group_set_device(grp, VLAN_ID, new_dev);
 
 	if (vlan_proc_add_dev(new_dev)<0)/* create it's proc entry */
 		printk(KERN_WARNING "VLAN: failed to add proc entry for %s\n",
···
 	printk(VLAN_DBG "Allocated new device successfully, returning.\n");
 #endif
 	return new_dev;
+
+out_free_arrays:
+	vlan_group_free(grp);
 
 out_free_unregister:
 	unregister_netdev(new_dev);
···
 	case NETDEV_CHANGE:
 		/* Propagate real device state to vlan devices */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
-			vlandev = grp->vlan_devices[i];
+			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;
 
···
 	case NETDEV_DOWN:
 		/* Put all VLANs for this dev in the down state too.  */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
-			vlandev = grp->vlan_devices[i];
+			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;
 
···
 	case NETDEV_UP:
 		/* Put all VLANs for this dev in the up state too.  */
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
-			vlandev = grp->vlan_devices[i];
+			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;
 
···
 		for (i = 0; i < VLAN_GROUP_ARRAY_LEN; i++) {
 			int ret;
 
-			vlandev = grp->vlan_devices[i];
+			vlandev = vlan_group_get_device(grp, i);
 			if (!vlandev)
 				continue;