Re: [PATCH net-next v4 3/4] net/tc: introduce TC_ACT_REINSERT.

[kbuild test robot <lkp@intel.com>]

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Hi Paolo,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on net-next/master]

url:    https://github.com/0day-ci/linux/commits/Paolo-Abeni/TC-refactor-act_mirred-packets-re-injection/20180729-102154
config: x86_64-randconfig-u0-07291027 (attached as .config)
compiler: gcc-5 (Debian 5.5.0-3) 5.4.1 20171010
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   In file included from arch/x86/include/asm/current.h:5:0,
                    from include/linux/sched.h:12,
                    from include/linux/uaccess.h:5,
                    from net/core/dev.c:75:
   net/core/dev.c: In function 'netif_receive_generic_xdp':
   net/core/dev.c:4255:28: error: 'struct sk_buff' has no member named 'tc_redirected'
     if (skb_cloned(skb) || skb->tc_redirected)
                               ^
   include/linux/compiler.h:58:30: note: in definition of macro '__trace_if'
     if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
                                 ^
>> net/core/dev.c:4255:2: note: in expansion of macro 'if'
     if (skb_cloned(skb) || skb->tc_redirected)
     ^
   net/core/dev.c:4255:28: error: 'struct sk_buff' has no member named 'tc_redirected'
     if (skb_cloned(skb) || skb->tc_redirected)
                               ^
   include/linux/compiler.h:58:42: note: in definition of macro '__trace_if'
     if (__builtin_constant_p(!!(cond)) ? !!(cond) :   \
                                             ^
>> net/core/dev.c:4255:2: note: in expansion of macro 'if'
     if (skb_cloned(skb) || skb->tc_redirected)
     ^
   net/core/dev.c:4255:28: error: 'struct sk_buff' has no member named 'tc_redirected'
     if (skb_cloned(skb) || skb->tc_redirected)
                               ^
   include/linux/compiler.h:69:16: note: in definition of macro '__trace_if'
      ______r = !!(cond);     \
                   ^
>> net/core/dev.c:4255:2: note: in expansion of macro 'if'
     if (skb_cloned(skb) || skb->tc_redirected)
     ^

vim +/if +4255 net/core/dev.c

  4241	
  4242	static u32 netif_receive_generic_xdp(struct sk_buff *skb,
  4243					     struct xdp_buff *xdp,
  4244					     struct bpf_prog *xdp_prog)
  4245	{
  4246		struct netdev_rx_queue *rxqueue;
  4247		void *orig_data, *orig_data_end;
  4248		u32 metalen, act = XDP_DROP;
  4249		int hlen, off;
  4250		u32 mac_len;
  4251	
  4252		/* Reinjected packets coming from act_mirred or similar should
  4253		 * not get XDP generic processing.
  4254		 */
> 4255		if (skb_cloned(skb) || skb->tc_redirected)
  4256			return XDP_PASS;
  4257	
  4258		/* XDP packets must be linear and must have sufficient headroom
  4259		 * of XDP_PACKET_HEADROOM bytes. This is the guarantee that also
  4260		 * native XDP provides, thus we need to do it here as well.
  4261		 */
  4262		if (skb_is_nonlinear(skb) ||
  4263		    skb_headroom(skb) < XDP_PACKET_HEADROOM) {
  4264			int hroom = XDP_PACKET_HEADROOM - skb_headroom(skb);
  4265			int troom = skb->tail + skb->data_len - skb->end;
  4266	
  4267			/* In case we have to go down the path and also linearize,
  4268			 * then lets do the pskb_expand_head() work just once here.
  4269			 */
  4270			if (pskb_expand_head(skb,
  4271					     hroom > 0 ? ALIGN(hroom, NET_SKB_PAD) : 0,
  4272					     troom > 0 ? troom + 128 : 0, GFP_ATOMIC))
  4273				goto do_drop;
  4274			if (skb_linearize(skb))
  4275				goto do_drop;
  4276		}
  4277	
  4278		/* The XDP program wants to see the packet starting at the MAC
  4279		 * header.
  4280		 */
  4281		mac_len = skb->data - skb_mac_header(skb);
  4282		hlen = skb_headlen(skb) + mac_len;
  4283		xdp->data = skb->data - mac_len;
  4284		xdp->data_meta = xdp->data;
  4285		xdp->data_end = xdp->data + hlen;
  4286		xdp->data_hard_start = skb->data - skb_headroom(skb);
  4287		orig_data_end = xdp->data_end;
  4288		orig_data = xdp->data;
  4289	
  4290		rxqueue = netif_get_rxqueue(skb);
  4291		xdp->rxq = &rxqueue->xdp_rxq;
  4292	
  4293		act = bpf_prog_run_xdp(xdp_prog, xdp);
  4294	
  4295		off = xdp->data - orig_data;
  4296		if (off > 0)
  4297			__skb_pull(skb, off);
  4298		else if (off < 0)
  4299			__skb_push(skb, -off);
  4300		skb->mac_header += off;
  4301	
  4302		/* check if bpf_xdp_adjust_tail was used. it can only "shrink"
  4303		 * pckt.
  4304		 */
  4305		off = orig_data_end - xdp->data_end;
  4306		if (off != 0) {
  4307			skb_set_tail_pointer(skb, xdp->data_end - xdp->data);
  4308			skb->len -= off;
  4309	
  4310		}
  4311	
  4312		switch (act) {
  4313		case XDP_REDIRECT:
  4314		case XDP_TX:
  4315			__skb_push(skb, mac_len);
  4316			break;
  4317		case XDP_PASS:
  4318			metalen = xdp->data - xdp->data_meta;
  4319			if (metalen)
  4320				skb_metadata_set(skb, metalen);
  4321			break;
  4322		default:
  4323			bpf_warn_invalid_xdp_action(act);
  4324			/* fall through */
  4325		case XDP_ABORTED:
  4326			trace_xdp_exception(skb->dev, xdp_prog, act);
  4327			/* fall through */
  4328		case XDP_DROP:
  4329		do_drop:
  4330			kfree_skb(skb);
  4331			break;
  4332		}
  4333	
  4334		return act;
  4335	}
  4336	

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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