Commit fbb192a8 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'skbuff-bitfields' 



Jakub Kicinski says:

====================
net: skbuff: hide some bitfield members

There is a number of protocol or subsystem specific fields
in struct sk_buff which are only accessed by one subsystem.
We can wrap them in ifdefs with minimal code impact.

This gives us a better chance to save a 2B and a 4B holes
resulting with the following savings (assuming a lucky
kernel config):

-	/* size: 232, cachelines: 4, members: 28 */
-	/* sum members: 227, holes: 1, sum holes: 4 */
-	/* sum bitfield members: 8 bits (1 bytes) */
+	/* size: 224, cachelines: 4, members: 28 */
 	/* forced alignments: 2 */
-	/* last cacheline: 40 bytes */
+	/* last cacheline: 32 bytes */

I think that the changes shouldn't be too controversial.
The only one I'm not 100% sure of is the SCTP one,
12 extra LoC for one bit.. But it did fit squarely
in the "this bit has only one user" category.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Acked-by: default avatarSimon Horman <horms@kernel.org>
parents 4edd97fb 48d80c39

include/linux/skbuff.h

+34 −4
Original line number Diff line number Diff line
@@ -934,7 +934,7 @@ struct sk_buff { 
	/* public: */

	__u8			pkt_type:3; /* see PKT_TYPE_MAX */

	__u8			ignore_df:1;

	__u8			nf_trace:1;

	__u8			dst_pending_confirm:1;

	__u8			ip_summed:2;

	__u8			ooo_okay:1;
@@ -949,12 +949,14 @@ struct sk_buff { 
	__u8			remcsum_offload:1;

	__u8			csum_complete_sw:1;

	__u8			csum_level:2;

	__u8			dst_pending_confirm:1;

	__u8			inner_protocol_type:1;



	__u8			l4_hash:1;

	__u8			sw_hash:1;

#ifdef CONFIG_WIRELESS

	__u8			wifi_acked_valid:1;

	__u8			wifi_acked:1;

#endif

	__u8			no_fcs:1;

	/* Indicates the inner headers are valid in the skbuff. */

	__u8			encapsulation:1;
@@ -964,8 +966,12 @@ struct sk_buff { 
	__u8			ndisc_nodetype:2;

#endif



#if IS_ENABLED(CONFIG_IP_VS)

	__u8			ipvs_property:1;

	__u8			inner_protocol_type:1;

#endif

#if IS_ENABLED(CONFIG_NETFILTER_XT_TARGET_TRACE) || IS_ENABLED(CONFIG_NF_TABLES)

	__u8			nf_trace:1;

#endif

#ifdef CONFIG_NET_SWITCHDEV

	__u8			offload_fwd_mark:1;

	__u8			offload_l3_fwd_mark:1;
@@ -981,12 +987,16 @@ struct sk_buff { 
	__u8			decrypted:1;

#endif

	__u8			slow_gro:1;

#if IS_ENABLED(CONFIG_IP_SCTP)

	__u8			csum_not_inet:1;

#endif



#ifdef CONFIG_NET_SCHED

	__u16			tc_index;	/* traffic control index */

#endif



	u16			alloc_cpu;



	union {

		__wsum		csum;

		struct {
@@ -1010,7 +1020,6 @@ struct sk_buff { 
		unsigned int	sender_cpu;

	};

#endif

	u16			alloc_cpu;

#ifdef CONFIG_NETWORK_SECMARK

	__u32		secmark;

#endif
@@ -1187,6 +1196,15 @@ static inline unsigned int skb_napi_id(const struct sk_buff *skb) 
#endif

}



static inline bool skb_wifi_acked_valid(const struct sk_buff *skb)

{

#ifdef CONFIG_WIRELESS

	return skb->wifi_acked_valid;

#else

	return 0;

#endif

}



/**

 * skb_unref - decrement the skb's reference count

 * @skb: buffer
@@ -5049,7 +5067,19 @@ static inline void skb_reset_redirect(struct sk_buff *skb) 


static inline bool skb_csum_is_sctp(struct sk_buff *skb)

{

#if IS_ENABLED(CONFIG_IP_SCTP)

	return skb->csum_not_inet;

#else

	return 0;

#endif

}



static inline void skb_reset_csum_not_inet(struct sk_buff *skb)

{

	skb->ip_summed = CHECKSUM_NONE;

#if IS_ENABLED(CONFIG_IP_SCTP)

	skb->csum_not_inet = 0;

#endif

}



static inline void skb_set_kcov_handle(struct sk_buff *skb,

include/net/sock.h

+1 −1
Original line number Diff line number Diff line
@@ -2697,7 +2697,7 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb) 
	else

		sock_write_timestamp(sk, kt);



	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb->wifi_acked_valid)

	if (sock_flag(sk, SOCK_WIFI_STATUS) && skb_wifi_acked_valid(skb))

		__sock_recv_wifi_status(msg, sk, skb);

}

net/core/dev.c

+1 −2
Original line number Diff line number Diff line
@@ -3315,8 +3315,7 @@ int skb_crc32c_csum_help(struct sk_buff *skb) 
						  skb->len - start, ~(__u32)0,

						  crc32c_csum_stub));

	*(__le32 *)(skb->data + offset) = crc32c_csum;

	skb->ip_summed = CHECKSUM_NONE;

	skb->csum_not_inet = 0;

	skb_reset_csum_not_inet(skb);

out:

	return ret;

}

net/core/skbuff.c

+2 −0
Original line number Diff line number Diff line
@@ -5189,6 +5189,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, 
}

EXPORT_SYMBOL_GPL(skb_tstamp_tx);



#ifdef CONFIG_WIRELESS

void skb_complete_wifi_ack(struct sk_buff *skb, bool acked)

{

	struct sock *sk = skb->sk;
@@ -5214,6 +5215,7 @@ void skb_complete_wifi_ack(struct sk_buff *skb, bool acked) 
		kfree_skb(skb);

}

EXPORT_SYMBOL_GPL(skb_complete_wifi_ack);

#endif /* CONFIG_WIRELESS */



/**

 * skb_partial_csum_set - set up and verify partial csum values for packet

net/sched/act_csum.c

+1 −2
Original line number Diff line number Diff line
@@ -376,8 +376,7 @@ static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl, 


	sctph->checksum = sctp_compute_cksum(skb,

					     skb_network_offset(skb) + ihl);

	skb->ip_summed = CHECKSUM_NONE;

	skb->csum_not_inet = 0;

	skb_reset_csum_not_inet(skb);



	return 1;

}