[3.19.y-ckt stable] Patch "can: fix loss of CAN frames in raw_rcv" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    can: fix loss of CAN frames in raw_rcv

to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue

This patch is scheduled to be released in version 3.19.y-ckt4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 42fd9bd1b9ba6558f060f9077070f71a9f31de90 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <socketcan at hartkopp.net>
Date: Sun, 21 Jun 2015 18:50:44 +0200
Subject: can: fix loss of CAN frames in raw_rcv

commit 36c01245eb8046c16eee6431e7dbfbb302635fa8 upstream.

As reported by Manfred Schlaegl here

   http://marc.info/?l=linux-netdev&m=143482089824232&w=2

commit 514ac99c64b "can: fix multiple delivery of a single CAN frame for
overlapping CAN filters" requires the skb->tstamp to be set to check for
identical CAN skbs.

As net timestamping is influenced by several players (netstamp_needed and
netdev_tstamp_prequeue) Manfred missed a proper timestamp which leads to
CAN frame loss.

As skb timestamping became now mandatory for CAN related skbs this patch
makes sure that received CAN skbs always have a proper timestamp set.
Maybe there's a better solution in the future but this patch fixes the
CAN frame loss so far.

Reported-by: Manfred Schlaegl <manfred.schlaegl at gmx.at>
Signed-off-by: Oliver Hartkopp <socketcan at hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/can/dev.c   | 5 +++++
 drivers/net/can/slcan.c | 1 +
 drivers/net/can/vcan.c  | 3 +++
 net/can/af_can.c        | 6 +++++-
 4 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
index 62ca0e8..44fc75f 100644
--- a/drivers/net/can/dev.c
+++ b/drivers/net/can/dev.c
@@ -438,6 +438,9 @@ unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
 		struct can_frame *cf = (struct can_frame *)skb->data;
 		u8 dlc = cf->can_dlc;

+		if (!(skb->tstamp.tv64))
+			__net_timestamp(skb);
+
 		netif_rx(priv->echo_skb[idx]);
 		priv->echo_skb[idx] = NULL;

@@ -574,6 +577,7 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
 	if (unlikely(!skb))
 		return NULL;

+	__net_timestamp(skb);
 	skb->protocol = htons(ETH_P_CAN);
 	skb->pkt_type = PACKET_BROADCAST;
 	skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -602,6 +606,7 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev,
 	if (unlikely(!skb))
 		return NULL;

+	__net_timestamp(skb);
 	skb->protocol = htons(ETH_P_CANFD);
 	skb->pkt_type = PACKET_BROADCAST;
 	skb->ip_summed = CHECKSUM_UNNECESSARY;
diff --git a/drivers/net/can/slcan.c b/drivers/net/can/slcan.c
index c837eb9..f64f529 100644
--- a/drivers/net/can/slcan.c
+++ b/drivers/net/can/slcan.c
@@ -207,6 +207,7 @@ static void slc_bump(struct slcan *sl)
 	if (!skb)
 		return;

+	__net_timestamp(skb);
 	skb->dev = sl->dev;
 	skb->protocol = htons(ETH_P_CAN);
 	skb->pkt_type = PACKET_BROADCAST;
diff --git a/drivers/net/can/vcan.c b/drivers/net/can/vcan.c
index 674f367..0ce868d 100644
--- a/drivers/net/can/vcan.c
+++ b/drivers/net/can/vcan.c
@@ -78,6 +78,9 @@ static void vcan_rx(struct sk_buff *skb, struct net_device *dev)
 	skb->dev       = dev;
 	skb->ip_summed = CHECKSUM_UNNECESSARY;

+	if (!(skb->tstamp.tv64))
+		__net_timestamp(skb);
+
 	netif_rx_ni(skb);
 }

diff --git a/net/can/af_can.c b/net/can/af_can.c
index 32d710e..689c818 100644
--- a/net/can/af_can.c
+++ b/net/can/af_can.c
@@ -310,8 +310,12 @@ int can_send(struct sk_buff *skb, int loop)
 		return err;
 	}

-	if (newskb)
+	if (newskb) {
+		if (!(newskb->tstamp.tv64))
+			__net_timestamp(newskb);
+
 		netif_rx_ni(newskb);
+	}

 	/* update statistics */
 	can_stats.tx_frames++;
--
1.9.1