bonding: use RCU protection for alb xmit path

The commit 278b20837511776dc9d5f6ee1c7fabd5479838bb
(bonding: initial RCU conversion) has convert the roundrobin,
active-backup, broadcast and xor xmit path to rcu protection,
the performance will be better for these mode, so this time,
convert xmit path for alb mode.

Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Cc: Nikolay Aleksandrov <nikolay@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 576cceae026ab0abbded5669369e6ca92d0abed3..02872405d35dc4a53d13473b31d1b517d22610d0 100644 (file)
--- a/drivers/net/bonding/bond_alb.c
+++ b/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);

diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 0bd04fbda8e91fccb88f9192fcea70e7c69e1996..bb5c731e2560880b81dc9cd1fac2c5888cd135fa 100644 (file)
--- a/drivers/net/bonding/bonding.h
+++ b/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
  */