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Commit 1fa17d4b authored by Oliver Hartkopp's avatar Oliver Hartkopp Committed by David S. Miller
Browse files

can: omit unneeded skb_clone() calls 



The AF_CAN core delivered always cloned sk_buffs to the AF_CAN
protocols, although this was _only_ needed by the can-raw protocol.
With this (additionally documented) change, the AF_CAN core calls the
callback functions of the registered AF_CAN protocols with the original
(uncloned) sk_buff pointer and let's the can-raw protocol do the
skb_clone() itself which omits all unneeded skb_clone() calls for other
AF_CAN protocols.

Signed-off-by: default avatarOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: default avatarUrs Thuermann <urs.thuermann@volkswagen.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 98658bc9

include/linux/can/core.h

+1 −1
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ 
#include <linux/skbuff.h>

#include <linux/netdevice.h>



#define CAN_VERSION "20081130"

#define CAN_VERSION "20090105"



/* increment this number each time you change some user-space interface */

#define CAN_ABI_VERSION "8"

net/can/af_can.c

+8 −7
Original line number Diff line number Diff line
@@ -414,6 +414,12 @@ static struct hlist_head *find_rcv_list(canid_t *can_id, canid_t *mask, 
 *  The filter can be inverted (CAN_INV_FILTER bit set in can_id) or it can

 *  filter for error frames (CAN_ERR_FLAG bit set in mask).

 *

 *  The provided pointer to the sk_buff is guaranteed to be valid as long as

 *  the callback function is running. The callback function must *not* free

 *  the given sk_buff while processing it's task. When the given sk_buff is

 *  needed after the end of the callback function it must be cloned inside

 *  the callback function with skb_clone().

 *

 * Return:

 *  0 on success

 *  -ENOMEM on missing cache mem to create subscription entry
@@ -569,14 +575,9 @@ EXPORT_SYMBOL(can_rx_unregister); 


static inline void deliver(struct sk_buff *skb, struct receiver *r)

{

	struct sk_buff *clone = skb_clone(skb, GFP_ATOMIC);



	if (clone) {

		clone->sk = skb->sk;

		r->func(clone, r->data);

	r->func(skb, r->data);

	r->matches++;

}

}



static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb)

{

net/can/bcm.c

+5 −7
Original line number Diff line number Diff line
@@ -633,7 +633,7 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) 
	hrtimer_cancel(&op->timer);



	if (op->can_id != rxframe->can_id)

		goto rx_freeskb;

		return;



	/* save rx timestamp */

	op->rx_stamp = skb->tstamp;
@@ -645,19 +645,19 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) 
	if (op->flags & RX_RTR_FRAME) {

		/* send reply for RTR-request (placed in op->frames[0]) */

		bcm_can_tx(op);

		goto rx_freeskb;

		return;

	}



	if (op->flags & RX_FILTER_ID) {

		/* the easiest case */

		bcm_rx_update_and_send(op, &op->last_frames[0], rxframe);

		goto rx_freeskb_starttimer;

		goto rx_starttimer;

	}



	if (op->nframes == 1) {

		/* simple compare with index 0 */

		bcm_rx_cmp_to_index(op, 0, rxframe);

		goto rx_freeskb_starttimer;

		goto rx_starttimer;

	}



	if (op->nframes > 1) {
@@ -678,10 +678,8 @@ static void bcm_rx_handler(struct sk_buff *skb, void *data) 
		}

	}



rx_freeskb_starttimer:

rx_starttimer:

	bcm_rx_starttimer(op);

rx_freeskb:

	kfree_skb(skb);

}



/*

net/can/raw.c

+8 −7
Original line number Diff line number Diff line
@@ -99,13 +99,14 @@ static void raw_rcv(struct sk_buff *skb, void *data) 
	struct raw_sock *ro = raw_sk(sk);

	struct sockaddr_can *addr;



	if (!ro->recv_own_msgs) {

	/* check the received tx sock reference */

		if (skb->sk == sk) {

			kfree_skb(skb);

	if (!ro->recv_own_msgs && skb->sk == sk)

		return;



	/* clone the given skb to be able to enqueue it into the rcv queue */

	skb = skb_clone(skb, GFP_ATOMIC);

	if (!skb)

		return;

		}

	}



	/*

	 *  Put the datagram to the queue so that raw_recvmsg() can