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net: dsa: Remove dangerous DSA_SKB_CLONE() macro

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This does not cause any bug now because it has no users, but its body
contains two pointer definitions within a code block:

		struct sk_buff *clone = _clone;	\
		struct sk_buff *skb = _skb;	\

When calling the macro as DSA_SKB_CLONE(clone, skb), these variables
would obscure the arguments that the macro was called with, and the
initializers would be a no-op instead of doing their job (undefined
behavior, by the way, but GCC nicely puts NULL pointers instead).

So simply remove this broken macro and leave users to simply call
"DSA_SKB_CB(skb)->clone = clone" by hand when needed.

There is one functional difference when doing what I just suggested
above: the control block won't be transferred from the original skb into
the clone. Since there's no foreseen need for the control block in the
clone ATM, this is ok.

Fixes: b68b0dd0fb2d ("net: dsa: Keep private info in the skb->cb")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vladimir Oltean 2019-05-11 23:14:46 +03:00 committed by David S. Miller
parent 8767137510
commit 506f0e09ce
1 changed files with 0 additions and 9 deletions
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9
include/net/dsa.h
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@ -105,15 +105,6 @@ struct __dsa_skb_cb {
#define DSA_SKB_CB_PRIV(skb) \
((void *)(skb)->cb + offsetof(struct __dsa_skb_cb, priv))
#define DSA_SKB_CB_CLONE(_clone, _skb) \
{ \
struct sk_buff *clone = _clone; \
struct sk_buff *skb = _skb; \
\
DSA_SKB_CB_COPY(clone, skb); \
DSA_SKB_CB(skb)->clone = clone; \
}
struct dsa_switch_tree {
struct list_head list;