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).

Willem de Bruijn committed 9 years ago

Commit e7246e11 parent d6264076 files · +23 −22Browse files

Unified · Split

6 files

drivers/net/ifb.c +1 −1
include/linux/skbuff.h +4 −1
include/net/sch_generic.h +11 −0
include/uapi/linux/pkt_cls.h +0 −6
net/core/dev.c +3 −7
net/sched/act_api.c +4 −7

drivers/net/ifb.c+1−1

@@ -81,7 +81,7 @@ static void ifb_ri_tasklet(unsigned long _txp) · 80 unmodified lines
81	81	u32 from = G_TC_FROM(skb->tc_verd);
82	82
83	83	skb->tc_verd = 0;
84		− skb->tc_verd = SET_TC_NCLS(skb->tc_verd);
	84	+ skb->tc_skip_classify = 1;
85	85
86	86	u64_stats_update_begin(&txp->tsync);
87	87	txp->tx_packets++;

include/linux/skbuff.h+4−1

@@ -589,6 +589,7 @@ static inline bool skb_mstamp_after(const struct skb_mstamp *t1, · 588 unmodified lines
589	589	* @pkt_type: Packet class
590	590	* @fclone: skbuff clone status
591	591	* @ipvs_property: skbuff is owned by ipvs
	592	+ * @tc_skip_classify: do not classify packet. set by IFB device
592	593	* @peeked: this packet has been seen already, so stats have been
593	594	* done for it, don't do them again
594	595	* @nf_trace: netfilter packet trace flag
@@ -749,7 +750,9 @@ struct sk_buff { · 154 unmodified lines
749	750	#ifdef CONFIG_NET_SWITCHDEV
750	751	__u8 offload_fwd_mark:1;
751	752	#endif
752		− /* 2, 4 or 5 bit hole */
	753	+#ifdef CONFIG_NET_CLS_ACT
	754	+ __u8 tc_skip_classify:1;
	755	+#endif
753	756
754	757	#ifdef CONFIG_NET_SCHED
755	758	__u16 tc_index; /* traffic control index */

include/net/sch_generic.h+11−0

@@ -418,6 +418,17 @@ static inline bool skb_at_tc_ingress(const struct sk_buff *skb) · 417 unmodified lines
418	418	#endif
419	419	}
420	420
	421	+static inline bool skb_skip_tc_classify(struct sk_buff *skb)
	422	+{
	423	+#ifdef CONFIG_NET_CLS_ACT
	424	+ if (skb->tc_skip_classify) {
	425	+ skb->tc_skip_classify = 0;
	426	+ return true;
	427	+ }
	428	+#endif
	429	+ return false;
	430	+}
	431	+
421	432	/* Reset all TX qdiscs greater then index of a device. */
422	433	static inline void qdisc_reset_all_tx_gt(struct net_device *dev, unsigned int i)
423	434	{

include/uapi/linux/pkt_cls.h+0−6

@@ -22,8 +22,6 @@ bit 6,7: Where this packet was last seen · 21 unmodified lines
22	22	1: on the Ingress
23	23	2: on the Egress
24	24
25		−bit 8: when set --> Request not to classify on ingress.
26		−
27	25	*
28	26	* */
29	27
@@ -36,10 +34,6 @@ bit 8: when set --> Request not to classify on ingress. · 6 unmodified lines
36	34	#define AT_INGRESS 0x1
37	35	#define AT_EGRESS 0x2
38	36
39		−#define TC_NCLS _TC_MAKEMASK1(8)
40		−#define SET_TC_NCLS(v) ( TC_NCLS \| (v & ~TC_NCLS))
41		−#define CLR_TC_NCLS(v) ( v & ~TC_NCLS)
42		−
43	37	#define S_TC_AT _TC_MAKE32(12)
44	38	#define M_TC_AT _TC_MAKEMASK(2,S_TC_AT)
45	39	#define G_TC_AT(x) _TC_GETVALUE(x,S_TC_AT,M_TC_AT)

net/core/dev.c+3−7

@@ -4093,12 +4093,8 @@ another_round: · 4092 unmodified lines
4093	4093	goto out;
4094	4094	}
4095	4095
4096		−#ifdef CONFIG_NET_CLS_ACT
4097		− if (skb->tc_verd & TC_NCLS) {
4098		− skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
4099		− goto ncls;
4100		− }
4101		−#endif
	4096	+ if (skb_skip_tc_classify(skb))
	4097	+ goto skip_classify;
4102	4098
4103	4099	if (pfmemalloc)
4104	4100	goto skip_taps;
@@ -4128,8 +4124,8 @@ skip_taps: · 23 unmodified lines
4128	4124	#endif
4129	4125	#ifdef CONFIG_NET_CLS_ACT
4130	4126	skb->tc_verd = 0;
4131		−ncls:
4132	4127	#endif
	4128	+skip_classify:
4133	4129	if (pfmemalloc && !skb_pfmemalloc_protocol(skb))
4134	4130	goto drop;
4135	4131

net/sched/act_api.c+4−7

@@ -426,11 +426,9 @@ int tcf_action_exec(struct sk_buff skb, struct tc_action *actions, · 425 unmodified lines
426	426	{
427	427	int ret = -1, i;
428	428
429		− if (skb->tc_verd & TC_NCLS) {
430		− skb->tc_verd = CLR_TC_NCLS(skb->tc_verd);
431		− ret = TC_ACT_OK;
432		− goto exec_done;
433		− }
	429	+ if (skb_skip_tc_classify(skb))
	430	+ return TC_ACT_OK;
	431	+
434	432	for (i = 0; i < nr_actions; i++) {
435	433	const struct tc_action *a = actions[i];
436	434
@@ -439,9 +437,8 @@ repeat: · 2 unmodified lines
439	437	if (ret == TC_ACT_REPEAT)
440	438	goto repeat; /* we need a ttl - JHS */
441	439	if (ret != TC_ACT_PIPE)
442		− goto exec_done;
	440	+ break;
443	441	}
444		−exec_done:
445	442	return ret;
446	443	}
447	444	EXPORT_SYMBOL(tcf_action_exec);