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authorOliver Hartkopp <oliver@hartkopp.net>2009-01-06 22:07:54 +0300
committerDavid S. Miller <davem@davemloft.net>2009-01-06 22:07:54 +0300
commit1fa17d4ba43d7e5aab5e90777b07da06524f6748 (patch)
treeebe8704bd84c51d29c17a8425b496a13b4935dc5 /net/can/af_can.c
parent98658bc9dc37cfb7c3bf5585ca73ce44aeb05c9e (diff)
downloadlinux-1fa17d4ba43d7e5aab5e90777b07da06524f6748.tar.xz
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 <oliver@hartkopp.net> Signed-off-by: Urs Thuermann <urs.thuermann@volkswagen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/can/af_can.c')
-rw-r--r--net/can/af_can.c15
1 files changed, 8 insertions, 7 deletions
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)