Commit d3b58c47 authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by Marc Kleine-Budde
Browse files

can: replace timestamp as unique skb attribute 



Commit 514ac99c "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.

Without timestamping to be required by user space applications this timestamp
was not generated which lead to commit 36c01245 "can: fix loss of CAN frames
in raw_rcv" - which forces the timestamp to be set in all CAN related skbuffs
by introducing several __net_timestamp() calls.

This forces e.g. out of tree drivers which are not using alloc_can{,fd}_skb()
to add __net_timestamp() after skbuff creation to prevent the frame loss fixed
in mainline Linux.

This patch removes the timestamp dependency and uses an atomic counter to
create an unique identifier together with the skbuff pointer.

Btw: the new skbcnt element introduced in struct can_skb_priv has to be
initialized with zero in out-of-tree drivers which are not using
alloc_can{,fd}_skb() too.

Signed-off-by: default avatarOliver Hartkopp <socketcan@hartkopp.net>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: default avatarMarc Kleine-Budde <mkl@pengutronix.de>
parent 2acb5c30

drivers/net/can/dev.c

+2 −5
Original line number Diff line number Diff line
@@ -440,9 +440,6 @@ 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;
@@ -578,7 +575,6 @@ 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;
@@ -589,6 +585,7 @@ struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf) 


	can_skb_reserve(skb);

	can_skb_prv(skb)->ifindex = dev->ifindex;

	can_skb_prv(skb)->skbcnt = 0;



	*cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));

	memset(*cf, 0, sizeof(struct can_frame));
@@ -607,7 +604,6 @@ 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;
@@ -618,6 +614,7 @@ struct sk_buff *alloc_canfd_skb(struct net_device *dev, 


	can_skb_reserve(skb);

	can_skb_prv(skb)->ifindex = dev->ifindex;

	can_skb_prv(skb)->skbcnt = 0;



	*cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));

	memset(*cfd, 0, sizeof(struct canfd_frame));

drivers/net/can/slcan.c

+1 −1
Original line number Diff line number Diff line
@@ -207,7 +207,6 @@ 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;
@@ -215,6 +214,7 @@ static void slc_bump(struct slcan *sl) 


	can_skb_reserve(skb);

	can_skb_prv(skb)->ifindex = sl->dev->ifindex;

	can_skb_prv(skb)->skbcnt = 0;



	memcpy(skb_put(skb, sizeof(struct can_frame)),

	       &cf, sizeof(struct can_frame));

drivers/net/can/vcan.c

+0 −3
Original line number Diff line number Diff line
@@ -78,9 +78,6 @@ 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);

}

include/linux/can/skb.h

+2 −0
Original line number Diff line number Diff line
@@ -27,10 +27,12 @@ 
/**

 * struct can_skb_priv - private additional data inside CAN sk_buffs

 * @ifindex:	ifindex of the first interface the CAN frame appeared on

 * @skbcnt:	atomic counter to have an unique id together with skb pointer

 * @cf:		align to the following CAN frame at skb->data

 */

struct can_skb_priv {

	int ifindex;

	int skbcnt;

	struct can_frame cf[0];

};

net/can/af_can.c

+7 −5
Original line number Diff line number Diff line
@@ -89,6 +89,8 @@ struct timer_list can_stattimer; /* timer for statistics update */ 
struct s_stats    can_stats;       /* packet statistics */

struct s_pstats   can_pstats;      /* receive list statistics */



static atomic_t skbcounter = ATOMIC_INIT(0);



/*

 * af_can socket functions

 */
@@ -310,12 +312,8 @@ int can_send(struct sk_buff *skb, int loop) 
		return err;

	}



	if (newskb) {

		if (!(newskb->tstamp.tv64))

			__net_timestamp(newskb);



	if (newskb)

		netif_rx_ni(newskb);

	}



	/* update statistics */

	can_stats.tx_frames++;
@@ -683,6 +681,10 @@ static void can_receive(struct sk_buff *skb, struct net_device *dev) 
	can_stats.rx_frames++;

	can_stats.rx_frames_delta++;



	/* create non-zero unique skb identifier together with *skb */

	while (!(can_skb_prv(skb)->skbcnt))

		can_skb_prv(skb)->skbcnt = atomic_inc_return(&skbcounter);



	rcu_read_lock();



	/* deliver the packet to sockets listening on all devices */

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