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authorOliver Hartkopp <socketcan@hartkopp.net>2014-01-30 10:11:28 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-03-06 21:30:03 -0800
commit8e88041811392a2d9ea989d6dc4a0430bf134700 (patch)
tree5cdcf70998349809f9e38cd2be561796e4473e7b /include
parentb9776f59637c237b85d493c2cb48bd3e14e4ba7b (diff)
can: add destructor for self generated skbs
[ Upstream commit 0ae89beb283a0db5980d1d4781c7d7be2f2810d6 ] 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 <socketcan@hartkopp.net> Tested-by: Andre Naujoks <nautsch2@gmail.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/can/skb.h38
1 files changed, 38 insertions, 0 deletions
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 <linux/types.h>
+#include <linux/skbuff.h>
#include <linux/can.h>
+#include <net/sock.h>
/*
* 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 */