netpoll: Only call ndo_start_xmit from a single place

Factor out the code that needs to surround ndo_start_xmit
from netpoll_send_skb_on_dev into netpoll_start_xmit.

It is an unfortunate fact that as the netpoll code has been maintained
the primary call site ndo_start_xmit learned how to handle vlans
and timestamps but the second call of ndo_start_xmit in queue_process
did not.

With the introduction of netpoll_start_xmit this associated logic now
happens at both call sites of ndo_start_xmit and should make it easy
for that to continue into the future.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 2c6379d..e2492d1 100644 (file)
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -69,6 +69,37 @@ module_param(carrier_timeout, uint, 0644);
 #define np_notice(np, fmt, ...)                                \
        pr_notice("%s: " fmt, np->name, ##__VA_ARGS__)
 
+static int netpoll_start_xmit(struct sk_buff *skb, struct net_device *dev,
+                             struct netdev_queue *txq)
+{
+       const struct net_device_ops *ops = dev->netdev_ops;
+       int status = NETDEV_TX_OK;
+       netdev_features_t features;
+
+       features = netif_skb_features(skb);
+
+       if (vlan_tx_tag_present(skb) &&
+           !vlan_hw_offload_capable(features, skb->vlan_proto)) {
+               skb = __vlan_put_tag(skb, skb->vlan_proto,
+                                    vlan_tx_tag_get(skb));
+               if (unlikely(!skb)) {
+                       /* This is actually a packet drop, but we
+                        * don't want the code that calls this
+                        * function to try and operate on a NULL skb.
+                        */
+                       goto out;
+               }
+               skb->vlan_tci = 0;
+       }
+
+       status = ops->ndo_start_xmit(skb, dev);
+       if (status == NETDEV_TX_OK)
+               txq_trans_update(txq);
+
+out:
+       return status;
+}
+
 static void queue_process(struct work_struct *work)
 {
        struct netpoll_info *npinfo =
@@ -78,7 +109,6 @@ static void queue_process(struct work_struct *work)
 
        while ((skb = skb_dequeue(&npinfo->txq))) {
                struct net_device *dev = skb->dev;
-               const struct net_device_ops *ops = dev->netdev_ops;
                struct netdev_queue *txq;
 
                if (!netif_device_present(dev) || !netif_running(dev)) {
@@ -91,7 +121,7 @@ static void queue_process(struct work_struct *work)
                local_irq_save(flags);
                __netif_tx_lock(txq, smp_processor_id());
                if (netif_xmit_frozen_or_stopped(txq) ||
-                   ops->ndo_start_xmit(skb, dev) != NETDEV_TX_OK) {
+                   netpoll_start_xmit(skb, dev, txq) != NETDEV_TX_OK) {
                        skb_queue_head(&npinfo->txq, skb);
                        __netif_tx_unlock(txq);
                        local_irq_restore(flags);
@@ -295,7 +325,6 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 {
        int status = NETDEV_TX_BUSY;
        unsigned long tries;
-       const struct net_device_ops *ops = dev->netdev_ops;
        /* It is up to the caller to keep npinfo alive. */
        struct netpoll_info *npinfo;
 
@@ -317,27 +346,9 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
                for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
                     tries > 0; --tries) {
                        if (__netif_tx_trylock(txq)) {
-                               if (!netif_xmit_stopped(txq)) {
-                                       if (vlan_tx_tag_present(skb) &&
-                                           !vlan_hw_offload_capable(netif_skb_features(skb),
-                                                                    skb->vlan_proto)) {
-                                               skb = __vlan_put_tag(skb, skb->vlan_proto, vlan_tx_tag_get(skb));
-                                               if (unlikely(!skb)) {
-                                                       /* This is actually a packet drop, but we
-                                                        * don't want the code at the end of this
-                                                        * function to try and re-queue a NULL skb.
-                                                        */
-                                                       status = NETDEV_TX_OK;
-                                                       goto unlock_txq;
-                                               }
-                                               skb->vlan_tci = 0;
-                                       }
-
-                                       status = ops->ndo_start_xmit(skb, dev);
-                                       if (status == NETDEV_TX_OK)
-                                               txq_trans_update(txq);
-                               }
-                       unlock_txq:
+                               if (!netif_xmit_stopped(txq))
+                                       status = netpoll_start_xmit(skb, dev, txq);
+
                                __netif_tx_unlock(txq);
 
                                if (status == NETDEV_TX_OK)
@@ -353,7 +364,7 @@ void netpoll_send_skb_on_dev(struct netpoll *np, struct sk_buff *skb,
 
                WARN_ONCE(!irqs_disabled(),
                        "netpoll_send_skb_on_dev(): %s enabled interrupts in poll (%pF)\n",
-                       dev->name, ops->ndo_start_xmit);
+                       dev->name, dev->netdev_ops->ndo_start_xmit);
 
        }