From 39e3ab6fded4d7e66e01a878f0cae23ddd480c3b Mon Sep 17 00:00:00 2001
From: Wolfgang Grandegger <wg@grandegger.com>
Date: Tue, 1 Sep 2009 05:26:12 +0000
Subject: [PATCH] can: add can_free_echo_skb() for upcoming drivers

This patch adds the function can_free_echo_skb to the CAN
device interface to allow upcoming drivers to release echo
skb's in case of error.

Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/can/dev.c   | 18 +++++++++++++++++-
 include/linux/can/dev.h |  1 +
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 1d29082d94ac32..f0b9a1e1db46d1 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -315,13 +315,29 @@ void can_get_echo_skb(struct net_device *dev, int idx)
 {
 	struct can_priv *priv = netdev_priv(dev);
 
-	if ((dev->flags & IFF_ECHO) && priv->echo_skb[idx]) {
+	if (priv->echo_skb[idx]) {
 		netif_rx(priv->echo_skb[idx]);
 		priv->echo_skb[idx] = NULL;
 	}
 }
 EXPORT_SYMBOL_GPL(can_get_echo_skb);
 
+/*
+  * Remove the skb from the stack and free it.
+  *
+  * The function is typically called when TX failed.
+  */
+void can_free_echo_skb(struct net_device *dev, int idx)
+{
+	struct can_priv *priv = netdev_priv(dev);
+
+	if (priv->echo_skb[idx]) {
+		kfree_skb(priv->echo_skb[idx]);
+		priv->echo_skb[idx] = NULL;
+	}
+}
+EXPORT_SYMBOL_GPL(can_free_echo_skb);
+
 /*
  * CAN device restart for bus-off recovery
  */
diff --git a/include/linux/can/dev.h b/include/linux/can/dev.h
index 4a37a56f6cdda1..5824b20b5fcbca 100644
--- a/include/linux/can/dev.h
+++ b/include/linux/can/dev.h
@@ -66,5 +66,6 @@ void can_bus_off(struct net_device *dev);
 
 void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev, int idx);
 void can_get_echo_skb(struct net_device *dev, int idx);
+void can_free_echo_skb(struct net_device *dev, int idx);
 
 #endif /* CAN_DEV_H */
-- 
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