From 1fa17d4ba43d7e5aab5e90777b07da06524f6748 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Tue, 6 Jan 2009 11:07:54 -0800 Subject: 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: Oliver Hartkopp Signed-off-by: Urs Thuermann Signed-off-by: David S. Miller --- net/can/af_can.c | 15 ++++++++------- net/can/bcm.c | 12 +++++------- net/can/raw.c | 15 ++++++++------- 3 files changed, 21 insertions(+), 21 deletions(-) (limited to 'net/can') diff --git a/net/can/af_can.c b/net/can/af_can.c index 3dadb338addd..fa417ca6cbe6 100644 --- a/net/can/af_can.c +++ b/net/can/af_can.c @@ -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 @@ -569,13 +575,8 @@ 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->matches++; - } + r->func(skb, r->data); + r->matches++; } static int can_rcv_filter(struct dev_rcv_lists *d, struct sk_buff *skb) diff --git a/net/can/bcm.c b/net/can/bcm.c index 6248ae2502c7..1649c8ab2c2f 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -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); } /* diff --git a/net/can/raw.c b/net/can/raw.c index 27aab63df467..0703cba4bf9f 100644 --- a/net/can/raw.c +++ b/net/can/raw.c @@ -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); - return; - } - } + /* check the received tx sock reference */ + 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 -- cgit v1.2.2