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Commit a48d189e authored by Stefano Brivio's avatar Stefano Brivio Committed by David S. Miller
Browse files

net: Move skb decrypted field, avoid explicity copy 



Commit 784abe24 ("net: Add decrypted field to skb")
introduced a 'decrypted' field that is explicitly copied on skb
copy and clone.

Move it between headers_start[0] and headers_end[0], so that we
don't need to copy it explicitly as it's copied by the memcpy()
in __copy_skb_header().

While at it, drop the assignment in __skb_clone(), it was
already redundant.

This doesn't change the size of sk_buff or cacheline boundaries.

The 15-bits hole before tc_index becomes a 14-bits hole, and
will be again a 15-bits hole when this change is merged with
commit 8b700862 ("net: Don't copy pfmemalloc flag in
__copy_skb_header()").

v2: as reported by kbuild test robot (oops, I forgot to build
    with CONFIG_TLS_DEVICE it seems), we can't use
    CHECK_SKB_FIELD() on a bit-field member. Just drop the
    check for the moment being, perhaps we could think of some
    magic to also check bit-field members one day.

Fixes: 784abe24 ("net: Add decrypted field to skb")
Signed-off-by: default avatarStefano Brivio <sbrivio@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent bf20a5c1

include/linux/skbuff.h

+4 −5
Original line number Diff line number Diff line
@@ -630,7 +630,6 @@ typedef unsigned char *sk_buff_data_t; 
 *	@hash: the packet hash

 *	@queue_mapping: Queue mapping for multiqueue devices

 *	@xmit_more: More SKBs are pending for this queue

 *	@decrypted: Decrypted SKB

 *	@ndisc_nodetype: router type (from link layer)

 *	@ooo_okay: allow the mapping of a socket to a queue to be changed

 *	@l4_hash: indicate hash is a canonical 4-tuple hash over transport
@@ -641,6 +640,7 @@ typedef unsigned char *sk_buff_data_t; 
 *	@no_fcs:  Request NIC to treat last 4 bytes as Ethernet FCS

 *	@csum_not_inet: use CRC32c to resolve CHECKSUM_PARTIAL

 *	@dst_pending_confirm: need to confirm neighbour

 *	@decrypted: Decrypted SKB

  *	@napi_id: id of the NAPI struct this skb came from

 *	@secmark: security marking

 *	@mark: Generic packet mark
@@ -737,11 +737,7 @@ struct sk_buff { 
				peeked:1,

				head_frag:1,

				xmit_more:1,

#ifdef CONFIG_TLS_DEVICE

				decrypted:1;

#else

				__unused:1;

#endif



	/* fields enclosed in headers_start/headers_end are copied

	 * using a single memcpy() in __copy_skb_header()
@@ -797,6 +793,9 @@ struct sk_buff { 
	__u8			tc_redirected:1;

	__u8			tc_from_ingress:1;

#endif

#ifdef CONFIG_TLS_DEVICE

	__u8			decrypted:1;

#endif



#ifdef CONFIG_NET_SCHED

	__u16			tc_index;	/* traffic control index */

net/core/skbuff.c

+0 −6
Original line number Diff line number Diff line
@@ -805,9 +805,6 @@ static void __copy_skb_header(struct sk_buff *new, const struct sk_buff *old) 
	 * It is not yet because we do not want to have a 16 bit hole

	 */

	new->queue_mapping = old->queue_mapping;

#ifdef CONFIG_TLS_DEVICE

	new->decrypted = old->decrypted;

#endif



	memcpy(&new->headers_start, &old->headers_start,

	       offsetof(struct sk_buff, headers_end) -
@@ -868,9 +865,6 @@ static struct sk_buff *__skb_clone(struct sk_buff *n, struct sk_buff *skb) 
	C(head_frag);

	C(data);

	C(truesize);

#ifdef CONFIG_TLS_DEVICE

	C(decrypted);

#endif

	refcount_set(&n->users, 1);



	atomic_inc(&(skb_shinfo(skb)->dataref));