1 files changed, 65 insertions, 46 deletions

diff --git a/drivers/net/ppp/ppp_generic.c b/drivers/net/ppp/ppp_generic.c
index e9b41777be80..2081da6c2144 100644
--- a/drivers/net/ppp/ppp_generic.c
+++ b/drivers/net/ppp/ppp_generic.c
@@ -134,7 +134,6 @@ struct ppp {
 	int		debug;		/* debug flags 70 */
 	struct slcompress *vj;		/* state for VJ header compression */
 	enum NPmode	npmode[NUM_NP];	/* what to do with each net proto 78 */
-	struct sk_buff	*xmit_pending;	/* a packet ready to go out 88 */
 	struct compressor *xcomp;	/* transmit packet compressor 8c */
 	void		*xc_state;	/* its internal state 90 */
 	struct compressor *rcomp;	/* receive decompressor 94 */
@@ -264,8 +263,8 @@ struct ppp_net {
 static int ppp_unattached_ioctl(struct net *net, struct ppp_file *pf,
 			struct file *file, unsigned int cmd, unsigned long arg);
 static void ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb);
-static void ppp_send_frame(struct ppp *ppp, struct sk_buff *skb);
-static void ppp_push(struct ppp *ppp);
+static int ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb);
+static int ppp_push(struct ppp *ppp, struct sk_buff *skb);
 static void ppp_channel_push(struct channel *pch);
 static void ppp_receive_frame(struct ppp *ppp, struct sk_buff *skb,
 			      struct channel *pch);
@@ -1651,26 +1650,44 @@ static void ppp_setup(struct net_device *dev)
  */
 
 /* Called to do any work queued up on the transmit side that can now be done */
+static void ppp_xmit_flush(struct ppp *ppp)
+{
+	struct sk_buff *skb;
+
+	while ((skb = skb_dequeue(&ppp->file.xq))) {
+		if (unlikely(!ppp_push(ppp, skb))) {
+			skb_queue_head(&ppp->file.xq, skb);
+			return;
+		}
+	}
+	/* If there's no work left to do, tell the core net code that we can
+	 * accept some more.
+	 */
+	netif_wake_queue(ppp->dev);
+}
+
 static void __ppp_xmit_process(struct ppp *ppp, struct sk_buff *skb)
 {
 	ppp_xmit_lock(ppp);
-	if (!ppp->closing) {
-		ppp_push(ppp);
-
-		if (skb)
+	if (unlikely(ppp->closing)) {
+		kfree_skb(skb);
+		goto out;
+	}
+	if (unlikely(ppp_prepare_tx_skb(ppp, &skb)))
+		goto out;
+	/* Fastpath: No backlog, just send the new skb. */
+	if (likely(skb_queue_empty(&ppp->file.xq))) {
+		if (unlikely(!ppp_push(ppp, skb))) {
 			skb_queue_tail(&ppp->file.xq, skb);
-		while (!ppp->xmit_pending &&
-		       (skb = skb_dequeue(&ppp->file.xq)))
-			ppp_send_frame(ppp, skb);
-		/* If there's no work left to do, tell the core net
-		   code that we can accept some more. */
-		if (!ppp->xmit_pending && !skb_peek(&ppp->file.xq))
-			netif_wake_queue(ppp->dev);
-		else
 			netif_stop_queue(ppp->dev);
-	} else {
-		kfree_skb(skb);
+		}
+		goto out;
 	}
+
+	/* Slowpath: Enqueue the new skb and process backlog */
+	skb_queue_tail(&ppp->file.xq, skb);
+	ppp_xmit_flush(ppp);
+out:
 	ppp_xmit_unlock(ppp);
 }
 
@@ -1757,13 +1774,15 @@ pad_compress_skb(struct ppp *ppp, struct sk_buff *skb)
 }
 
 /*
- * Compress and send a frame.
- * The caller should have locked the xmit path,
- * and xmit_pending should be 0.
+ * Compress and prepare to send a frame.
+ * The caller should have locked the xmit path.
+ * Returns 1 if the skb was consumed, 0 if it can be passed to ppp_push().
+ * @pskb is updated if a compressor is in use.
  */
-static void
-ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
+static int
+ppp_prepare_tx_skb(struct ppp *ppp, struct sk_buff **pskb)
 {
+	struct sk_buff *skb = *pskb;
 	int proto = PPP_PROTO(skb);
 	struct sk_buff *new_skb;
 	int len;
@@ -1784,7 +1803,7 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 					      "PPP: outbound frame "
 					      "not passed\n");
 			kfree_skb(skb);
-			return;
+			return 1;
 		}
 		/* if this packet passes the active filter, record the time */
 		if (!(ppp->active_filter &&
@@ -1832,6 +1851,7 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 			}
 			consume_skb(skb);
 			skb = new_skb;
+			*pskb = skb;
 			cp = skb_put(skb, len + 2);
 			cp[0] = 0;
 			cp[1] = proto;
@@ -1858,6 +1878,7 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 		if (!new_skb)
 			goto drop;
 		skb = new_skb;
+		*pskb = skb;
 	}
 
 	/*
@@ -1869,42 +1890,38 @@ ppp_send_frame(struct ppp *ppp, struct sk_buff *skb)
 			goto drop;
 		skb_queue_tail(&ppp->file.rq, skb);
 		wake_up_interruptible(&ppp->file.rwait);
-		return;
+		return 1;
 	}
 
-	ppp->xmit_pending = skb;
-	ppp_push(ppp);
-	return;
+	return 0;
 
  drop:
 	kfree_skb(skb);
 	++ppp->dev->stats.tx_errors;
+	return 1;
 }
 
 /*
- * Try to send the frame in xmit_pending.
+ * Try to send the frame.
  * The caller should have the xmit path locked.
+ * Returns 1 if the skb was consumed, 0 if not.
  */
-static void
-ppp_push(struct ppp *ppp)
+static int
+ppp_push(struct ppp *ppp, struct sk_buff *skb)
 {
 	struct list_head *list;
 	struct channel *pch;
-	struct sk_buff *skb = ppp->xmit_pending;
-
-	if (!skb)
-		return;
 
 	list = &ppp->channels;
 	if (list_empty(list)) {
 		/* nowhere to send the packet, just drop it */
-		ppp->xmit_pending = NULL;
 		kfree_skb(skb);
-		return;
+		return 1;
 	}
 
 	if ((ppp->flags & SC_MULTILINK) == 0) {
 		struct ppp_channel *chan;
+		int ret;
 		/* not doing multilink: send it down the first channel */
 		list = list->next;
 		pch = list_entry(list, struct channel, clist);
@@ -1916,27 +1933,26 @@ ppp_push(struct ppp *ppp)
 			 * skb but linearization failed
 			 */
 			kfree_skb(skb);
-			ppp->xmit_pending = NULL;
+			ret = 1;
 			goto out;
 		}
 
-		if (chan->ops->start_xmit(chan, skb))
-			ppp->xmit_pending = NULL;
+		ret = chan->ops->start_xmit(chan, skb);
 
 out:
 		spin_unlock(&pch->downl);
-		return;
+		return ret;
 	}
 
 #ifdef CONFIG_PPP_MULTILINK
 	/* Multilink: fragment the packet over as many links
 	   as can take the packet at the moment. */
 	if (!ppp_mp_explode(ppp, skb))
-		return;
+		return 0;
 #endif /* CONFIG_PPP_MULTILINK */
 
-	ppp->xmit_pending = NULL;
 	kfree_skb(skb);
+	return 1;
 }
 
 #ifdef CONFIG_PPP_MULTILINK
@@ -2005,7 +2021,7 @@ static int ppp_mp_explode(struct ppp *ppp, struct sk_buff *skb)
 	 * performance if we have a lot of channels.
 	 */
 	if (nfree == 0 || nfree < navail / 2)
-		return 0; /* can't take now, leave it in xmit_pending */
+		return 0; /* can't take now, leave it in transmit queue */
 
 	/* Do protocol field compression */
 	if (skb_linearize(skb))
@@ -2199,8 +2215,12 @@ static void __ppp_channel_push(struct channel *pch, struct ppp *ppp)
 	spin_unlock(&pch->downl);
 	/* see if there is anything from the attached unit to be sent */
 	if (skb_queue_empty(&pch->file.xq)) {
-		if (ppp)
-			__ppp_xmit_process(ppp, NULL);
+		if (ppp) {
+			ppp_xmit_lock(ppp);
+			if (!ppp->closing)
+				ppp_xmit_flush(ppp);
+			ppp_xmit_unlock(ppp);
+		}
 	}
 }
 
@@ -3460,7 +3480,6 @@ static void ppp_destroy_interface(struct ppp *ppp)
 	}
 #endif /* CONFIG_PPP_FILTER */
 
-	kfree_skb(ppp->xmit_pending);
 	free_percpu(ppp->xmit_recursion);
 
 	free_netdev(ppp->dev);