bonding: remove packet cloning in recv_probe()

Cloning all packets in input path have a significant cost.

Use skb_header_pointer()/skb_copy_bits() instead of pskb_may_pull() so
that recv_probe handlers (bond_3ad_lacpdu_recv / bond_arp_rcv /
rlb_arp_recv ) dont touch input skb.

bond_handle_frame() can avoid the skb_clone()/dev_kfree_skb()

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jay Vosburgh <fubar@us.ibm.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Cc: Jiri Bohac <jbohac@suse.cz>
Cc: Nicolas de Pesloüan <nicolas.2p.debian@free.fr>
Cc: Maciej Żenczykowski <maze@google.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 36 insertions, 40 deletions

diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index 3463b469e657..3031e0413114 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -2460,18 +2460,21 @@ out:
         return NETDEV_TX_OK;
 }
 
-int bond_3ad_lacpdu_recv(struct sk_buff *skb, struct bonding *bond,
-                          struct slave *slave)
+int bond_3ad_lacpdu_recv(const struct sk_buff *skb, struct bonding *bond,
+                         struct slave *slave)
 {
         int ret = RX_HANDLER_ANOTHER;
+        struct lacpdu *lacpdu, _lacpdu;
+
         if (skb->protocol != PKT_TYPE_LACPDU)
                 return ret;
 
-        if (!pskb_may_pull(skb, sizeof(struct lacpdu)))
+        lacpdu = skb_header_pointer(skb, 0, sizeof(_lacpdu), &_lacpdu);
+        if (!lacpdu)
                 return ret;
 
         read_lock(&bond->lock);
-        ret = bond_3ad_rx_indication((struct lacpdu *) skb->data, slave, skb->len);
+        ret = bond_3ad_rx_indication(lacpdu, slave, skb->len);
         read_unlock(&bond->lock);
         return ret;
 }
diff --git a/drivers/net/bonding/bond_3ad.h b/drivers/net/bonding/bond_3ad.h
index 5ee7e3c45db7..0cfaa4afdece 100644
--- a/drivers/net/bonding/bond_3ad.h
+++ b/drivers/net/bonding/bond_3ad.h
@@ -274,8 +274,8 @@ void bond_3ad_adapter_duplex_changed(struct slave *slave);
 void bond_3ad_handle_link_change(struct slave *slave, char link);
 int  bond_3ad_get_active_agg_info(struct bonding *bond, struct ad_info *ad_info);
 int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev);
-int bond_3ad_lacpdu_recv(struct sk_buff *skb, struct bonding *bond,
-                          struct slave *slave);
+int bond_3ad_lacpdu_recv(const struct sk_buff *skb, struct bonding *bond,
+                         struct slave *slave);
 int bond_3ad_set_carrier(struct bonding *bond);
 void bond_3ad_update_lacp_rate(struct bonding *bond);
 #endif //__BOND_3AD_H__
diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 0f59c1564e53..ef3791a09ad8 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -342,27 +342,17 @@ static void rlb_update_entry_from_arp(struct bonding *bond, struct arp_pkt *arp)
         _unlock_rx_hashtbl_bh(bond);
 }
 
-static int rlb_arp_recv(struct sk_buff *skb, struct bonding *bond,
-                         struct slave *slave)
+static int rlb_arp_recv(const struct sk_buff *skb, struct bonding *bond,
+                        struct slave *slave)
 {
-        struct arp_pkt *arp;
+        struct arp_pkt *arp, _arp;
 
         if (skb->protocol != cpu_to_be16(ETH_P_ARP))
                 goto out;
 
-        arp = (struct arp_pkt *) skb->data;
-        if (!arp) {
-                pr_debug("Packet has no ARP data\n");
+        arp = skb_header_pointer(skb, 0, sizeof(_arp), &_arp);
+        if (!arp)
                 goto out;
-        }
-
-        if (!pskb_may_pull(skb, arp_hdr_len(bond->dev)))
-                goto out;
-
-        if (skb->len < sizeof(struct arp_pkt)) {
-                pr_debug("Packet is too small to be an ARP\n");
-                goto out;
-        }
 
         if (arp->op_code == htons(ARPOP_REPLY)) {
                 /* update rx hash table for this ARP */
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 2ee8cf9e8a3b..9e2301eef386 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1444,8 +1444,8 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
         struct sk_buff *skb = *pskb;
         struct slave *slave;
         struct bonding *bond;
-        int (*recv_probe)(struct sk_buff *, struct bonding *,
-                                struct slave *);
+        int (*recv_probe)(const struct sk_buff *, struct bonding *,
+                          struct slave *);
         int ret = RX_HANDLER_ANOTHER;
 
         skb = skb_share_check(skb, GFP_ATOMIC);
@@ -1462,15 +1462,10 @@ static rx_handler_result_t bond_handle_frame(struct sk_buff **pskb)
 
         recv_probe = ACCESS_ONCE(bond->recv_probe);
         if (recv_probe) {
-                struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC);
-
-                if (likely(nskb)) {
-                        ret = recv_probe(nskb, bond, slave);
-                        dev_kfree_skb(nskb);
-                        if (ret == RX_HANDLER_CONSUMED) {
-                                consume_skb(skb);
-                                return ret;
-                        }
+                ret = recv_probe(skb, bond, slave);
+                if (ret == RX_HANDLER_CONSUMED) {
+                        consume_skb(skb);
+                        return ret;
                 }
         }
 
@@ -2737,25 +2732,31 @@ static void bond_validate_arp(struct bonding *bond, struct slave *slave, __be32
         }
 }
 
-static int bond_arp_rcv(struct sk_buff *skb, struct bonding *bond,
-                         struct slave *slave)
+static int bond_arp_rcv(const struct sk_buff *skb, struct bonding *bond,
+                        struct slave *slave)
 {
-        struct arphdr *arp;
+        struct arphdr *arp = (struct arphdr *)skb->data;
         unsigned char *arp_ptr;
         __be32 sip, tip;
+        int alen;
 
         if (skb->protocol != __cpu_to_be16(ETH_P_ARP))
                 return RX_HANDLER_ANOTHER;
 
         read_lock(&bond->lock);
+        alen = arp_hdr_len(bond->dev);
 
         pr_debug("bond_arp_rcv: bond %s skb->dev %s\n",
                  bond->dev->name, skb->dev->name);
 
-        if (!pskb_may_pull(skb, arp_hdr_len(bond->dev)))
-                goto out_unlock;
+        if (alen > skb_headlen(skb)) {
+                arp = kmalloc(alen, GFP_ATOMIC);
+                if (!arp)
+                        goto out_unlock;
+                if (skb_copy_bits(skb, 0, arp, alen) < 0)
+                        goto out_unlock;
+        }
 
-        arp = arp_hdr(skb);
         if (arp->ar_hln != bond->dev->addr_len ||
             skb->pkt_type == PACKET_OTHERHOST ||
             skb->pkt_type == PACKET_LOOPBACK ||
@@ -2790,6 +2791,8 @@ static int bond_arp_rcv(struct sk_buff *skb, struct bonding *bond,
 
 out_unlock:
         read_unlock(&bond->lock);
+        if (arp != (struct arphdr *)skb->data)
+                kfree(arp);
         return RX_HANDLER_ANOTHER;
 }
 
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 4581aa5ccaba..f8af2fcd3d16 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -218,8 +218,8 @@ struct bonding {
         struct   slave *primary_slave;
         bool     force_primary;
         s32      slave_cnt; /* never change this value outside the attach/detach wrappers */
-        int     (*recv_probe)(struct sk_buff *, struct bonding *,
-                               struct slave *);
+        int     (*recv_probe)(const struct sk_buff *, struct bonding *,
+                              struct slave *);
         rwlock_t lock;
         rwlock_t curr_slave_lock;
         u8       send_peer_notif;