Subject: Re: [PATCH v2 net-next 4/6] net: dsa: tag_rtl8_4: add realtek 8 byte protocol 4 tag

From: kernel test robot <[email-masked]>
Date: Thu, 14 Oct 2021 08:46:46 +0800

Hi "Alvin,

Thank you for the patch! Yet something to improve:

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

url:    https://github.com/0day-ci/linux/commits/Alvin-ipraga/net-dsa-add-support-for-RTL8365MB-VC/20211013-225955
base:   https://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git d1f24712a86abd04d82cf4b00fb4ab8ff2d23c8a
config: powerpc-randconfig-r023-20211013 (attached as .config)
compiler: powerpc-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/e17d422e49ba2acbf43ae144fcce940cc06152a0
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Alvin-ipraga/net-dsa-add-support-for-RTL8365MB-VC/20211013-225955
        git checkout e17d422e49ba2acbf43ae144fcce940cc06152a0
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=powerpc 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email-masked]>

All errors (new ones prefixed by >>):

   In file included from include/linux/byteorder/big_endian.h:5,
                    from arch/powerpc/include/uapi/asm/byteorder.h:14,
                    from include/asm-generic/bitops/le.h:7,
                    from arch/powerpc/include/asm/bitops.h:265,
                    from include/linux/bitops.h:33,
                    from include/linux/kernel.h:12,
                    from include/linux/skbuff.h:13,
                    from include/linux/if_ether.h:19,
                    from include/linux/etherdevice.h:20,
                    from net/dsa/tag_rtl8_4.c:64:
   net/dsa/tag_rtl8_4.c: In function 'rtl8_4_tag_xmit':
>> net/dsa/tag_rtl8_4.c:108:24: error: implicit declaration of function 'FIELD_PREP' [-Werror=implicit-function-declaration]
     108 |         tag[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB));
         |                        ^~~~~~~~~~
   include/uapi/linux/byteorder/big_endian.h:41:51: note: in definition of macro '__cpu_to_be16'
      41 | #define __cpu_to_be16(x) ((__force __be16)(__u16)(x))
         |                                                   ^
   include/linux/byteorder/generic.h:141:18: note: in expansion of macro '___htons'
     141 | #define htons(x) ___htons(x)
         |                  ^~~~~~~~
   net/dsa/tag_rtl8_4.c:108:18: note: in expansion of macro 'htons'
     108 |         tag[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB));
         |                  ^~~~~
   net/dsa/tag_rtl8_4.c: In function 'rtl8_4_tag_rcv':
>> net/dsa/tag_rtl8_4.c:142:17: error: implicit declaration of function 'FIELD_GET'; did you mean 'FOLL_GET'? [-Werror=implicit-function-declaration]
     142 |         proto = FIELD_GET(RTL8_4_PROTOCOL, ntohs(tag[1]));
         |                 ^~~~~~~~~
         |                 FOLL_GET
   cc1: some warnings being treated as errors

vim +/FIELD_PREP +108 net/dsa/tag_rtl8_4.c

  > 64	#include <linux/etherdevice.h>
    65	
    66	#include "dsa_priv.h"
    67	
    68	/* Protocols supported:
    69	 *
    70	 * 0x04 = RTL8365MB DSA protocol
    71	 */
    72	
    73	#define RTL8_4_TAG_LEN			8
    74	
    75	#define RTL8_4_PROTOCOL			GENMASK(15, 8)
    76	#define   RTL8_4_PROTOCOL_RTL8365MB	0x04
    77	#define RTL8_4_REASON			GENMASK(7, 0)
    78	#define   RTL8_4_REASON_FORWARD		0
    79	#define   RTL8_4_REASON_TRAP		80
    80	
    81	#define RTL8_4_LEARN_DIS		BIT(5)
    82	
    83	#define RTL8_4_TX			GENMASK(3, 0)
    84	#define RTL8_4_RX			GENMASK(10, 0)
    85	
    86	static struct sk_buff *rtl8_4_tag_xmit(struct sk_buff *skb,
    87					       struct net_device *dev)
    88	{
    89		struct dsa_port *dp = dsa_slave_to_port(dev);
    90		__be16 *tag;
    91	
    92		/* Pad out so the (stripped) packet is at least 64 bytes long
    93		 * (including FCS), otherwise the switch will drop the packet.
    94		 * Then we need an additional 8 bytes for the Realtek tag.
    95		 */
    96		if (unlikely(__skb_put_padto(skb, ETH_ZLEN + RTL8_4_TAG_LEN, false)))
    97			return NULL;
    98	
    99		skb_push(skb, RTL8_4_TAG_LEN);
   100	
   101		dsa_alloc_etype_header(skb, RTL8_4_TAG_LEN);
   102		tag = dsa_etype_header_pos_tx(skb);
   103	
   104		/* Set Realtek EtherType */
   105		tag[0] = htons(ETH_P_REALTEK);
   106	
   107		/* Set Protocol; zero REASON */
 > 108		tag[1] = htons(FIELD_PREP(RTL8_4_PROTOCOL, RTL8_4_PROTOCOL_RTL8365MB));
   109	
   110		/* Zero FID_EN, FID, PRI_EN, PRI, KEEP; set LEARN_DIS */
   111		tag[2] = htons(FIELD_PREP(RTL8_4_LEARN_DIS, 1));
   112	
   113		/* Zero ALLOW; set RX (CPU->switch) forwarding port mask */
   114		tag[3] = htons(FIELD_PREP(RTL8_4_RX, BIT(dp->index)));
   115	
   116		return skb;
   117	}
   118	
   119	static struct sk_buff *rtl8_4_tag_rcv(struct sk_buff *skb,
   120					      struct net_device *dev)
   121	{
   122		__be16 *tag;
   123		u16 etype;
   124		u8 reason;
   125		u8 proto;
   126		u8 port;
   127	
   128		if (unlikely(!pskb_may_pull(skb, RTL8_4_TAG_LEN)))
   129			return NULL;
   130	
   131		tag = dsa_etype_header_pos_rx(skb);
   132	
   133		/* Parse Realtek EtherType */
   134		etype = ntohs(tag[0]);
   135		if (unlikely(etype != ETH_P_REALTEK)) {
   136			dev_warn_ratelimited(&dev->dev,
   137					     "non-realtek ethertype 0x%04x\n", etype);
   138			return NULL;
   139		}
   140	
   141		/* Parse Protocol */
 > 142		proto = FIELD_GET(RTL8_4_PROTOCOL, ntohs(tag[1]));
   143		if (unlikely(proto != RTL8_4_PROTOCOL_RTL8365MB)) {
   144			dev_warn_ratelimited(&dev->dev,
   145					     "unknown realtek protocol 0x%02x\n",
   146					     proto);
   147			return NULL;
   148		}
   149	
   150		/* Parse REASON */
   151		reason = FIELD_GET(RTL8_4_REASON, ntohs(tag[1]));
   152	
   153		/* Parse TX (switch->CPU) */
   154		port = FIELD_GET(RTL8_4_TX, ntohs(tag[3]));
   155		skb->dev = dsa_master_find_slave(dev, 0, port);
   156		if (!skb->dev) {
   157			dev_warn_ratelimited(&dev->dev,
   158					     "could not find slave for port %d\n",
   159					     port);
   160			return NULL;
   161		}
   162	
   163		/* Remove tag and recalculate checksum */
   164		skb_pull_rcsum(skb, RTL8_4_TAG_LEN);
   165	
   166		dsa_strip_etype_header(skb, RTL8_4_TAG_LEN);
   167	
   168		if (reason != RTL8_4_REASON_TRAP)
   169			dsa_default_offload_fwd_mark(skb);
   170	
   171		return skb;
   172	}
   173	

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