On Tue, 17 Jul 2018 12:33:06 +1000
Stephen Rothwell [off-list ref] wrote:

Hi all,

Today's linux-next merge of the net-next tree got a conflict in:

  include/linux/skbuff.h

between commit:

  8b7008620b84 ("net: Don't copy pfmemalloc flag in __copy_skb_header()")

from the net tree and commit:

  784abe24c903 ("net: Add decrypted field to skb")

from the net-next tree.

[...]

@@@ -736,7 -737,11 +738,11 @@@ struct sk_buff 
  				peeked:1,
  				head_frag:1,
  				xmit_more:1,
 +				pfmemalloc:1;
+ #ifdef CONFIG_TLS_DEVICE
 -				decrypted:1;
 -#else
 -				__unused:1;
++	__u8			decrypted:1,
++				__unused:7;
+ #endif
  
  	/* fields enclosed in headers_start/headers_end are copied
  	 * using a single memcpy() in __copy_skb_header()

I checked the layout of sk_buff after this, we already had a 1-byte
hole there, that now becomes a 7-bits hole (or disappears with
__unused). That's fine.

Boris, I read your commit 784abe24c903 ("net: Add decrypted field to
skb") just now.

I think 'decrypted' shouldn't go there, because you then copy it on
copy and clone: if you move if after headers_start[0] you don't need to
explicitly copy it in __copy_skb_header().

While at it, the copy you added in __skb_clone() is redundant (no
matter the position of 'decrypted').

I can send a clean-up patch against net-next. I guess this might cause
again a linux-next merge conflict, but it's again trivial (the __unused
field above would go away).

-- 
Stefano