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Commit e7246e12 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

net-tc: extract skip classify bit from tc_verd 



Packets sent by the IFB device skip subsequent tc classification.
A single bit governs this state. Move it out of tc_verd in
anticipation of removing that __u16 completely.

The new bitfield tc_skip_classify temporarily uses one bit of a
hole, until tc_verd is removed completely in a follow-up patch.

Remove the bit hole comment. It could be 2, 3, 4 or 5 bits long.
With that many options, little value in documenting it.

Introduce a helper function to deduplicate the logic in the two
sites that check this bit.

The field tc_skip_classify is set only in IFB on skbs cloned in
act_mirred, so original packet sources do not have to clear the
bit when reusing packets (notably, pktgen and octeon).

Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d6264071

drivers/net/ifb.c

+1 −1
Original line number Diff line number Diff line
@@ -81,7 +81,7 @@ static void ifb_ri_tasklet(unsigned long _txp) 
		u32 from = G_TC_FROM(skb->tc_verd);



		skb->tc_verd = 0;

		skb->tc_verd = SET_TC_NCLS(skb->tc_verd);

		skb->tc_skip_classify = 1;



		u64_stats_update_begin(&txp->tsync);

		txp->tx_packets++;

include/linux/skbuff.h

+4 −1
Original line number Diff line number Diff line
@@ -589,6 +589,7 @@ static inline bool skb_mstamp_after(const struct skb_mstamp *t1, 
 *	@pkt_type: Packet class

 *	@fclone: skbuff clone status

 *	@ipvs_property: skbuff is owned by ipvs

 *	@tc_skip_classify: do not classify packet. set by IFB device

 *	@peeked: this packet has been seen already, so stats have been

 *		done for it, don't do them again

 *	@nf_trace: netfilter packet trace flag
@@ -749,7 +750,9 @@ struct sk_buff { 
#ifdef CONFIG_NET_SWITCHDEV

	__u8			offload_fwd_mark:1;

#endif

	/* 2, 4 or 5 bit hole */

#ifdef CONFIG_NET_CLS_ACT

	__u8			tc_skip_classify:1;

#endif



#ifdef CONFIG_NET_SCHED

	__u16			tc_index;	/* traffic control index */

include/net/sch_generic.h

+11 −0
Original line number Diff line number Diff line
@@ -418,6 +418,17 @@ static inline bool skb_at_tc_ingress(const struct sk_buff *skb) 
#endif

}



static inline bool skb_skip_tc_classify(struct sk_buff *skb)

{

#ifdef CONFIG_NET_CLS_ACT

	if (skb->tc_skip_classify) {

		skb->tc_skip_classify = 0;

		return true;

	}

#endif

	return false;

}



/* Reset all TX qdiscs greater then index of a device.  */

static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)

{

include/uapi/linux/pkt_cls.h

+0 −6
Original line number Diff line number Diff line
@@ -22,8 +22,6 @@ bit 6,7: Where this packet was last seen 
1: on the Ingress

2: on the Egress



bit 8: when set --> Request not to classify on ingress. 



 *

 * */
@@ -36,10 +34,6 @@ bit 8: when set --> Request not to classify on ingress. 
#define AT_INGRESS	0x1

#define AT_EGRESS	0x2



#define TC_NCLS          _TC_MAKEMASK1(8)

#define SET_TC_NCLS(v)   ( TC_NCLS | (v & ~TC_NCLS))

#define CLR_TC_NCLS(v)   ( v & ~TC_NCLS)



#define S_TC_AT          _TC_MAKE32(12)

#define M_TC_AT          _TC_MAKEMASK(2,S_TC_AT)

#define G_TC_AT(x)       _TC_GETVALUE(x,S_TC_AT,M_TC_AT)

net/core/dev.c

+3 −7
Original line number Diff line number Diff line
@@ -4093,12 +4093,8 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc) 
			goto out;

	}



#ifdef CONFIG_NET_CLS_ACT

	if (skb->tc_verd & TC_NCLS) {

		skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);

		goto ncls;

	}

#endif

	if (skb_skip_tc_classify(skb))

		goto skip_classify;



	if (pfmemalloc)

		goto skip_taps;
@@ -4128,8 +4124,8 @@ static int __netif_receive_skb_core(struct sk_buff *skb, bool pfmemalloc) 
#endif

#ifdef CONFIG_NET_CLS_ACT

	skb->tc_verd = 0;

ncls:

#endif

skip_classify:

	if (pfmemalloc && !skb_pfmemalloc_protocol(skb))

		goto drop;