Phonet: get rid of deferred work on the transmission path

Signed-off-by: Rémi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 28 insertions, 63 deletions

diff --git a/net/phonet/pep-gprs.c b/net/phonet/pep-gprs.c
index a2873203dff2..b0ceac2d6cd1 100644
--- a/net/phonet/pep-gprs.c
+++ b/net/phonet/pep-gprs.c
@@ -41,11 +41,6 @@ struct gprs_dev {
         void                    (*old_write_space)(struct sock *);
 
         struct net_device       *dev;
-
-        struct sk_buff_head     tx_queue;
-        struct work_struct      tx_work;
-        spinlock_t              tx_lock;
-        unsigned                tx_max;
 };
 
 static __be16 gprs_type_trans(struct sk_buff *skb)
@@ -66,6 +61,14 @@ static __be16 gprs_type_trans(struct sk_buff *skb)
         return htons(0);
 }
 
+static void gprs_writeable(struct gprs_dev *gp)
+{
+        struct net_device *dev = gp->dev;
+
+        if (pep_writeable(gp->sk))
+                netif_wake_queue(dev);
+}
+
 /*
  * Socket callbacks
  */
@@ -157,14 +160,9 @@ static void gprs_data_ready(struct sock *sk, int len)
 static void gprs_write_space(struct sock *sk)
 {
         struct gprs_dev *gp = sk->sk_user_data;
-        struct net_device *dev = gp->dev;
-        unsigned credits = pep_writeable(sk);
 
-        spin_lock_bh(&gp->tx_lock);
-        gp->tx_max = credits;
-        if (credits > skb_queue_len(&gp->tx_queue) && netif_running(dev))
-                netif_wake_queue(dev);
-        spin_unlock_bh(&gp->tx_lock);
+        if (netif_running(gp->dev))
+                gprs_writeable(gp);
 }
 
 /*
@@ -175,22 +173,21 @@ static int gprs_open(struct net_device *dev)
 {
         struct gprs_dev *gp = netdev_priv(dev);
 
-        gprs_write_space(gp->sk);
+        gprs_writeable(gp);
         return 0;
 }
 
 static int gprs_close(struct net_device *dev)
 {
-        struct gprs_dev *gp = netdev_priv(dev);
-
         netif_stop_queue(dev);
-        flush_work(&gp->tx_work);
         return 0;
 }
 
 static int gprs_xmit(struct sk_buff *skb, struct net_device *dev)
 {
         struct gprs_dev *gp = netdev_priv(dev);
+        struct sock *sk = gp->sk;
+        int len, err;
 
         switch (skb->protocol) {
         case  htons(ETH_P_IP):
@@ -201,51 +198,24 @@ static int gprs_xmit(struct sk_buff *skb, struct net_device *dev)
                 return 0;
         }
 
-        spin_lock(&gp->tx_lock);
-        if (likely(skb_queue_len(&gp->tx_queue) < gp->tx_max)) {
-                skb_queue_tail(&gp->tx_queue, skb);
-                skb = NULL;
-        }
-        if (skb_queue_len(&gp->tx_queue) >= gp->tx_max)
-                netif_stop_queue(dev);
-        spin_unlock(&gp->tx_lock);
-
-        schedule_work(&gp->tx_work);
-        if (unlikely(skb))
+        skb_orphan(skb);
+        skb_set_owner_w(skb, sk);
+        len = skb->len;
+        err = pep_write(sk, skb);
+        if (err) {
+                LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
+                                dev->name, err);
+                dev->stats.tx_aborted_errors++;
+                dev->stats.tx_errors++;
                 dev_kfree_skb(skb);
-        return 0;
-}
-
-static void gprs_tx(struct work_struct *work)
-{
-        struct gprs_dev *gp = container_of(work, struct gprs_dev, tx_work);
-        struct net_device *dev = gp->dev;
-        struct sock *sk = gp->sk;
-        struct sk_buff *skb;
-
-        while ((skb = skb_dequeue(&gp->tx_queue)) != NULL) {
-                int err;
-
-                dev->stats.tx_bytes += skb->len;
+        } else {
                 dev->stats.tx_packets++;
-
-                skb_orphan(skb);
-                skb_set_owner_w(skb, sk);
-
-                lock_sock(sk);
-                err = pep_write(sk, skb);
-                if (err) {
-                        LIMIT_NETDEBUG(KERN_WARNING"%s: TX error (%d)\n",
-                                        dev->name, err);
-                        dev->stats.tx_aborted_errors++;
-                        dev->stats.tx_errors++;
-                }
-                release_sock(sk);
+                dev->stats.tx_bytes += len;
         }
 
-        lock_sock(sk);
-        gprs_write_space(sk);
-        release_sock(sk);
+        if (!pep_writeable(sk))
+                netif_stop_queue(dev);
+        return 0;
 }
 
 static int gprs_set_mtu(struct net_device *dev, int new_mtu)
@@ -297,11 +267,8 @@ int gprs_attach(struct sock *sk)
         if (!dev)
                 return -ENOMEM;
         gp = netdev_priv(dev);
+        gp->sk = sk;
         gp->dev = dev;
-        gp->tx_max = 0;
-        spin_lock_init(&gp->tx_lock);
-        skb_queue_head_init(&gp->tx_queue);
-        INIT_WORK(&gp->tx_work, gprs_tx);
 
         netif_stop_queue(dev);
         err = register_netdev(dev);
@@ -328,9 +295,7 @@ int gprs_attach(struct sock *sk)
         sk->sk_data_ready       = gprs_data_ready;
         sk->sk_write_space      = gprs_write_space;
         release_sock(sk);
-
         sock_hold(sk);
-        gp->sk = sk;
 
         printk(KERN_DEBUG"%s: attached\n", dev->name);
         return dev->ifindex;