From 0ae89beb283a0db5980d1d4781c7d7be2f2810d6 Mon Sep 17 00:00:00 2001 From: Oliver Hartkopp Date: Thu, 30 Jan 2014 10:11:28 +0100 Subject: can: add destructor for self generated skbs Self generated skbuffs in net/can/bcm.c are setting a skb->sk reference but no explicit destructor which is enforced since Linux 3.11 with commit 376c7311bdb6 (net: add a temporary sanity check in skb_orphan()). This patch adds some helper functions to make sure that a destructor is properly defined when a sock reference is assigned to a CAN related skb. To create an unshared skb owned by the original sock a common helper function has been introduced to replace open coded functions to create CAN echo skbs. Signed-off-by: Oliver Hartkopp Tested-by: Andre Naujoks Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller --- include/linux/can/skb.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) (limited to 'include/linux/can') diff --git a/include/linux/can/skb.h b/include/linux/can/skb.h index 2f0543f7510c..f9bbbb472663 100644 --- a/include/linux/can/skb.h +++ b/include/linux/can/skb.h @@ -11,7 +11,9 @@ #define CAN_SKB_H #include +#include #include +#include /* * The struct can_skb_priv is used to transport additional information along @@ -42,4 +44,40 @@ static inline void can_skb_reserve(struct sk_buff *skb) skb_reserve(skb, sizeof(struct can_skb_priv)); } +static inline void can_skb_destructor(struct sk_buff *skb) +{ + sock_put(skb->sk); +} + +static inline void can_skb_set_owner(struct sk_buff *skb, struct sock *sk) +{ + if (sk) { + sock_hold(sk); + skb->destructor = can_skb_destructor; + skb->sk = sk; + } +} + +/* + * returns an unshared skb owned by the original sock to be echo'ed back + */ +static inline struct sk_buff *can_create_echo_skb(struct sk_buff *skb) +{ + if (skb_shared(skb)) { + struct sk_buff *nskb = skb_clone(skb, GFP_ATOMIC); + + if (likely(nskb)) { + can_skb_set_owner(nskb, skb->sk); + consume_skb(skb); + return nskb; + } else { + kfree_skb(skb); + return NULL; + } + } + + /* we can assume to have an unshared skb with proper owner */ + return skb; +} + #endif /* CAN_SKB_H */ -- cgit v1.2.3-59-g8ed1b