Merge branch 'bonding_rcu'

bonding: patchset for rcu use in bonding

====================
The Patch Set convert the xmit of 3ad and alb mode to use rcu lock.
dd rtnl lock and remove read lock for bond sysfs.

v2 because the bond_for_each_slave_rcu without rcu_read_lock() will occurs one warming, so
add new function for alb xmit path to avoid warming.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_3ad.c

@@ -2344,7 +2344,7 @@ int __bond_3ad_get_active_agg_info(struct bonding *bond,
 	struct slave *slave;
 	struct port *port;
 
-	bond_for_each_slave(bond, slave, iter) {
+	bond_for_each_slave_rcu(bond, slave, iter) {
 		port = &(SLAVE_AD_INFO(slave).port);
 		if (port->aggregator && port->aggregator->is_active) {
 			aggregator = port->aggregator;
@@ -2369,9 +2369,9 @@ int bond_3ad_get_active_agg_info(struct bonding *bond, struct ad_info *ad_info)
 {
 	int ret;
 
-	read_lock(&bond->lock);
+	rcu_read_lock();
 	ret = __bond_3ad_get_active_agg_info(bond, ad_info);
-	read_unlock(&bond->lock);
+	rcu_read_unlock();
 
 	return ret;
 }
@@ -2388,7 +2388,6 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 	int res = 1;
 	int agg_id;
 
-	read_lock(&bond->lock);
 	if (__bond_3ad_get_active_agg_info(bond, &ad_info)) {
 		pr_debug("%s: Error: __bond_3ad_get_active_agg_info failed\n",
 			 dev->name);
@@ -2406,7 +2405,7 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 	slave_agg_no = bond_xmit_hash(bond, skb, slaves_in_agg);
 	first_ok_slave = NULL;
 
-	bond_for_each_slave(bond, slave, iter) {
+	bond_for_each_slave_rcu(bond, slave, iter) {
 		agg = SLAVE_AD_INFO(slave).port.aggregator;
 		if (!agg || agg->aggregator_identifier != agg_id)
 			continue;
@@ -2436,7 +2435,6 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
 		res = bond_dev_queue_xmit(bond, skb, first_ok_slave->dev);
 
 out:
-	read_unlock(&bond->lock);
 	if (res) {
 		/* no suitable interface, frame not sent */
 		kfree_skb(skb);

drivers/net/bonding/bond_alb.c

@@ -230,7 +230,7 @@ static struct slave *tlb_get_least_loaded_slave(struct bonding *bond)
 	max_gap = LLONG_MIN;
 
 	/* Find the slave with the largest gap */
-	bond_for_each_slave(bond, slave, iter) {
+	bond_for_each_slave_rcu(bond, slave, iter) {
 		if (SLAVE_IS_OK(slave)) {
 			long long gap = compute_gap(slave);
 
@@ -412,6 +412,39 @@ static struct slave *rlb_next_rx_slave(struct bonding *bond)
 	return rx_slave;
 }
 
+/* Caller must hold rcu_read_lock() for read */
+static struct slave *__rlb_next_rx_slave(struct bonding *bond)
+{
+	struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
+	struct slave *before = NULL, *rx_slave = NULL, *slave;
+	struct list_head *iter;
+	bool found = false;
+
+	bond_for_each_slave_rcu(bond, slave, iter) {
+		if (!SLAVE_IS_OK(slave))
+			continue;
+		if (!found) {
+			if (!before || before->speed < slave->speed)
+				before = slave;
+		} else {
+			if (!rx_slave || rx_slave->speed < slave->speed)
+				rx_slave = slave;
+		}
+		if (slave == bond_info->rx_slave)
+			found = true;
+	}
+	/* we didn't find anything after the current or we have something
+	 * better before and up to the current slave
+	 */
+	if (!rx_slave || (before && rx_slave->speed < before->speed))
+		rx_slave = before;
+
+	if (rx_slave)
+		bond_info->rx_slave = rx_slave;
+
+	return rx_slave;
+}
+
 /* teach the switch the mac of a disabled slave
  * on the primary for fault tolerance
  *
@@ -628,12 +661,14 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon
 {
 	struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
 	struct arp_pkt *arp = arp_pkt(skb);
-	struct slave *assigned_slave;
+	struct slave *assigned_slave, *curr_active_slave;
 	struct rlb_client_info *client_info;
 	u32 hash_index = 0;
 
 	_lock_rx_hashtbl(bond);
 
+	curr_active_slave = rcu_dereference(bond->curr_active_slave);
+
 	hash_index = _simple_hash((u8 *)&arp->ip_dst, sizeof(arp->ip_dst));
 	client_info = &(bond_info->rx_hashtbl[hash_index]);
 
@@ -658,14 +693,14 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon
 			 * that the new client can be assigned to this entry.
 			 */
 			if (bond->curr_active_slave &&
-			    client_info->slave != bond->curr_active_slave) {
-				client_info->slave = bond->curr_active_slave;
+			    client_info->slave != curr_active_slave) {
+				client_info->slave = curr_active_slave;
 				rlb_update_client(client_info);
 			}
 		}
 	}
 	/* assign a new slave */
-	assigned_slave = rlb_next_rx_slave(bond);
+	assigned_slave = __rlb_next_rx_slave(bond);
 
 	if (assigned_slave) {
 		if (!(client_info->assigned &&
@@ -728,7 +763,7 @@ static struct slave *rlb_arp_xmit(struct sk_buff *skb, struct bonding *bond)
 	/* Don't modify or load balance ARPs that do not originate locally
 	 * (e.g.,arrive via a bridge).
 	 */
-	if (!bond_slave_has_mac(bond, arp->mac_src))
+	if (!bond_slave_has_mac_rcu(bond, arp->mac_src))
 		return NULL;
 
 	if (arp->op_code == htons(ARPOP_REPLY)) {
@@ -1343,11 +1378,6 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 	skb_reset_mac_header(skb);
 	eth_data = eth_hdr(skb);
 
-	/* make sure that the curr_active_slave do not change during tx
-	 */
-	read_lock(&bond->lock);
-	read_lock(&bond->curr_slave_lock);
-
 	switch (ntohs(skb->protocol)) {
 	case ETH_P_IP: {
 		const struct iphdr *iph = ip_hdr(skb);
@@ -1429,12 +1459,12 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 
 	if (!tx_slave) {
 		/* unbalanced or unassigned, send through primary */
-		tx_slave = bond->curr_active_slave;
+		tx_slave = rcu_dereference(bond->curr_active_slave);
 		bond_info->unbalanced_load += skb->len;
 	}
 
 	if (tx_slave && SLAVE_IS_OK(tx_slave)) {
-		if (tx_slave != bond->curr_active_slave) {
+		if (tx_slave != rcu_dereference(bond->curr_active_slave)) {
 			memcpy(eth_data->h_source,
 			       tx_slave->dev->dev_addr,
 			       ETH_ALEN);
@@ -1449,8 +1479,6 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
 		}
 	}
 
-	read_unlock(&bond->curr_slave_lock);
-	read_unlock(&bond->lock);
 	if (res) {
 		/* no suitable interface, frame not sent */
 		kfree_skb(skb);

drivers/net/bonding/bond_sysfs.c

@@ -179,7 +179,9 @@ static ssize_t bonding_show_slaves(struct device *d,
 	struct slave *slave;
 	int res = 0;
 
-	read_lock(&bond->lock);
+	if (!rtnl_trylock())
+		return restart_syscall();
+
 	bond_for_each_slave(bond, slave, iter) {
 		if (res > (PAGE_SIZE - IFNAMSIZ)) {
 			/* not enough space for another interface name */
@@ -190,7 +192,9 @@ static ssize_t bonding_show_slaves(struct device *d,
 		}
 		res += sprintf(buf + res, "%s ", slave->dev->name);
 	}
-	read_unlock(&bond->lock);
+
+	rtnl_unlock();
+
 	if (res)
 		buf[res-1] = '\n'; /* eat the leftover space */
 
@@ -626,6 +630,9 @@ static ssize_t bonding_store_arp_targets(struct device *d,
 	unsigned long *targets_rx;
 	int ind, i, j, ret = -EINVAL;
 
+	if (!rtnl_trylock())
+		return restart_syscall();
+
 	targets = bond->params.arp_targets;
 	newtarget = in_aton(buf + 1);
 	/* look for adds */
@@ -699,6 +706,7 @@ static ssize_t bonding_store_arp_targets(struct device *d,
 
 	ret = count;
 out:
+	rtnl_unlock();
 	return ret;
 }
 static DEVICE_ATTR(arp_ip_target, S_IRUGO | S_IWUSR , bonding_show_arp_targets, bonding_store_arp_targets);
@@ -1467,7 +1475,6 @@ static ssize_t bonding_show_queue_id(struct device *d,
 	if (!rtnl_trylock())
 		return restart_syscall();
 
-	read_lock(&bond->lock);
 	bond_for_each_slave(bond, slave, iter) {
 		if (res > (PAGE_SIZE - IFNAMSIZ - 6)) {
 			/* not enough space for another interface_name:queue_id pair */
@@ -1479,9 +1486,9 @@ static ssize_t bonding_show_queue_id(struct device *d,
 		res += sprintf(buf + res, "%s:%d ",
 			       slave->dev->name, slave->queue_id);
 	}
-	read_unlock(&bond->lock);
 	if (res)
 		buf[res-1] = '\n'; /* eat the leftover space */
+
 	rtnl_unlock();
 
 	return res;
@@ -1530,8 +1537,6 @@ static ssize_t bonding_store_queue_id(struct device *d,
 	if (!sdev)
 		goto err_no_cmd;
 
-	read_lock(&bond->lock);
-
 	/* Search for thes slave and check for duplicate qids */
 	update_slave = NULL;
 	bond_for_each_slave(bond, slave, iter) {
@@ -1542,23 +1547,20 @@ static ssize_t bonding_store_queue_id(struct device *d,
 			 */
 			update_slave = slave;
 		else if (qid && qid == slave->queue_id) {
-			goto err_no_cmd_unlock;
+			goto err_no_cmd;
 		}
 	}
 
 	if (!update_slave)
-		goto err_no_cmd_unlock;
+		goto err_no_cmd;
 
 	/* Actually set the qids for the slave */
 	update_slave->queue_id = qid;
 
-	read_unlock(&bond->lock);
 out:
 	rtnl_unlock();
 	return ret;
 
-err_no_cmd_unlock:
-	read_unlock(&bond->lock);
 err_no_cmd:
 	pr_info("invalid input for queue_id set for %s.\n",
 		bond->dev->name);
@@ -1591,6 +1593,9 @@ static ssize_t bonding_store_slaves_active(struct device *d,
 	struct list_head *iter;
 	struct slave *slave;
 
+	if (!rtnl_trylock())
+		return restart_syscall();
+
 	if (sscanf(buf, "%d", &new_value) != 1) {
 		pr_err("%s: no all_slaves_active value specified.\n",
 		       bond->dev->name);
@@ -1610,7 +1615,6 @@ static ssize_t bonding_store_slaves_active(struct device *d,
 		goto out;
 	}
 
-	read_lock(&bond->lock);
 	bond_for_each_slave(bond, slave, iter) {
 		if (!bond_is_active_slave(slave)) {
 			if (new_value)
@@ -1619,8 +1623,8 @@ static ssize_t bonding_store_slaves_active(struct device *d,
 				slave->inactive = 1;
 		}
 	}
-	read_unlock(&bond->lock);
 out:
+	rtnl_unlock();
 	return ret;
 }
 static DEVICE_ATTR(all_slaves_active, S_IRUGO | S_IWUSR,

drivers/net/bonding/bonding.h

@@ -464,6 +464,20 @@ static inline struct slave *bond_slave_has_mac(struct bonding *bond,
 	return NULL;
 }
 
+/* Caller must hold rcu_read_lock() for read */
+static inline struct slave *bond_slave_has_mac_rcu(struct bonding *bond,
+					       const u8 *mac)
+{
+	struct list_head *iter;
+	struct slave *tmp;
+
+	bond_for_each_slave_rcu(bond, tmp, iter)
+		if (ether_addr_equal_64bits(mac, tmp->dev->dev_addr))
+			return tmp;
+
+	return NULL;
+}
+
 /* Check if the ip is present in arp ip list, or first free slot if ip == 0
  * Returns -1 if not found, index if found
  */