af-packet: Use existing netdev reference for bound sockets.

This saves a network device lookup on each packet transmitted,
for sockets that are bound to a network device.

Signed-off-by: Ben Greear <greearb@candelatech.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 15 insertions, 12 deletions

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 636b75c15a63..67f6749a0a45 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -974,7 +974,8 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
         struct sk_buff *skb;
         struct net_device *dev;
         __be16 proto;
-        int ifindex, err, reserve = 0;
+        bool need_rls_dev = false;
+        int err, reserve = 0;
         void *ph;
         struct sockaddr_ll *saddr = (struct sockaddr_ll *)msg->msg_name;
         int tp_len, size_max;
@@ -986,7 +987,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
 
         err = -EBUSY;
         if (saddr == NULL) {
-                ifindex = po->ifindex;
+                dev = po->prot_hook.dev;
                 proto   = po->num;
                 addr    = NULL;
         } else {
@@ -997,12 +998,12 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg)
                                         + offsetof(struct sockaddr_ll,
                                                 sll_addr)))
                         goto out;
-                ifindex = saddr->sll_ifindex;
                 proto   = saddr->sll_protocol;
                 addr    = saddr->sll_addr;
+                dev = dev_get_by_index(sock_net(&po->sk), saddr->sll_ifindex);
+                need_rls_dev = true;
         }
 
-        dev = dev_get_by_index(sock_net(&po->sk), ifindex);
         err = -ENXIO;
         if (unlikely(dev == NULL))
                 goto out;
@@ -1088,7 +1089,8 @@ out_status:
         __packet_set_status(po, ph, status);
         kfree_skb(skb);
 out_put:
-        dev_put(dev);
+        if (need_rls_dev)
+                dev_put(dev);
 out:
         mutex_unlock(&po->pg_vec_lock);
         return err;
@@ -1126,8 +1128,9 @@ static int packet_snd(struct socket *sock,
         struct sk_buff *skb;
         struct net_device *dev;
         __be16 proto;
+        bool need_rls_dev = false;
         unsigned char *addr;
-        int ifindex, err, reserve = 0;
+        int err, reserve = 0;
         struct virtio_net_hdr vnet_hdr = { 0 };
         int offset = 0;
         int vnet_hdr_len;
@@ -1139,7 +1142,7 @@ static int packet_snd(struct socket *sock,
          */
 
         if (saddr == NULL) {
-                ifindex = po->ifindex;
+                dev = po->prot_hook.dev;
                 proto   = po->num;
                 addr    = NULL;
         } else {
@@ -1148,13 +1151,12 @@ static int packet_snd(struct socket *sock,
                         goto out;
                 if (msg->msg_namelen < (saddr->sll_halen + offsetof(struct sockaddr_ll, sll_addr)))
                         goto out;
-                ifindex = saddr->sll_ifindex;
                 proto   = saddr->sll_protocol;
                 addr    = saddr->sll_addr;
+                dev = dev_get_by_index(sock_net(sk), saddr->sll_ifindex);
+                need_rls_dev = true;
         }
 
-
-        dev = dev_get_by_index(sock_net(sk), ifindex);
         err = -ENXIO;
         if (dev == NULL)
                 goto out_unlock;
@@ -1285,14 +1287,15 @@ static int packet_snd(struct socket *sock,
         if (err > 0 && (err = net_xmit_errno(err)) != 0)
                 goto out_unlock;
 
-        dev_put(dev);
+        if (need_rls_dev)
+                dev_put(dev);
 
         return len;
 
 out_free:
         kfree_skb(skb);
 out_unlock:
-        if (dev)
+        if (dev && need_rls_dev)
                 dev_put(dev);
 out:
         return err;