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>

1 files changed, 36 insertions, 25 deletions

diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 2c6379da295c..e2492d176ae7 100644
--- 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);
 
         }