From cff0d6e6edac7672b3f915bb4fb59f279243b7f9 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Tue, 3 Aug 2010 00:31:48 -0700
Subject: can-raw: Fix skb_orphan_try handling

Commit fc6055a5ba31e2c14e36e8939f9bf2b6d586a7f5 (net: Introduce
skb_orphan_try()) allows an early orphan of the skb and takes care on
tx timestamping, which needs the sk-reference in the skb on driver level.
So does the can-raw socket, which has not been taken into account here.

The patch below adds a 'prevent_sk_orphan' bit in the skb tx shared info,
which fixes the problem discovered by Matthias Fuchs here:

      http://marc.info/?t=128030411900003&r=1&w=2

Even if it's not a primary tx timestamp topic it fits well into some skb
shared tx context. Or should be find a different place for the information to
protect the sk reference until it reaches the driver level?

Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 include/linux/skbuff.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'include/linux/skbuff.h')

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index d89876b806a0..d20d9e7a9bbd 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -169,6 +169,7 @@ struct skb_shared_hwtstamps {
  * @software:		generate software time stamp
  * @in_progress:	device driver is going to provide
  *			hardware time stamp
+ * @prevent_sk_orphan:	make sk reference available on driver level
  * @flags:		all shared_tx flags
  *
  * These flags are attached to packets as part of the
@@ -178,7 +179,8 @@ union skb_shared_tx {
 	struct {
 		__u8	hardware:1,
 			software:1,
-			in_progress:1;
+			in_progress:1,
+			prevent_sk_orphan:1;
 	};
 	__u8 flags;
 };
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