Hi Christophe,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on staging/staging-testing]

url:    https://github.com/0day-ci/linux/commits/Christophe-JAILLET/staging-rtl8188eu-Use-existing-arc4-implementation/20210410-213656
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git 32abcac8037da5dc570c22abf266cbb92eee9fc9
config: x86_64-randconfig-s021-20210416 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce:
        # apt-get install sparse
        # sparse version: v0.6.3-280-g2cd6d34e-dirty
        # https://github.com/0day-ci/linux/commit/ea2709e5f53370e588967f79d2eb847555ea9d3b
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Christophe-JAILLET/staging-rtl8188eu-Use-existing-arc4-implementation/20210410-213656
        git checkout ea2709e5f53370e588967f79d2eb847555ea9d3b
        # save the attached .config to linux build tree
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' W=1 ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   ld: drivers/staging/rtl8712/rtl871x_security.o: in function `r8712_wep_encrypt':
>> drivers/staging/rtl8712/rtl871x_security.c:126: undefined reference to `arc4_setkey'
>> ld: drivers/staging/rtl8712/rtl871x_security.c:127: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.c:129: undefined reference to `arc4_crypt'
>> ld: drivers/staging/rtl8712/rtl871x_security.c:137: undefined reference to `arc4_setkey'
   ld: drivers/staging/rtl8712/rtl871x_security.c:138: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.c:140: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.o: in function `r8712_wep_decrypt':
   drivers/staging/rtl8712/rtl871x_security.c:177: undefined reference to `arc4_setkey'
   ld: drivers/staging/rtl8712/rtl871x_security.c:178: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.o: in function `r8712_tkip_encrypt':
   drivers/staging/rtl8712/rtl871x_security.c:550: undefined reference to `arc4_setkey'
   ld: drivers/staging/rtl8712/rtl871x_security.c:551: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.c:553: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.c:562: undefined reference to `arc4_setkey'
   ld: drivers/staging/rtl8712/rtl871x_security.c:563: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.c:565: undefined reference to `arc4_crypt'
   ld: drivers/staging/rtl8712/rtl871x_security.o: in function `r8712_tkip_decrypt':
   drivers/staging/rtl8712/rtl871x_security.c:625: undefined reference to `arc4_setkey'
   ld: drivers/staging/rtl8712/rtl871x_security.c:626: undefined reference to `arc4_crypt'


vim +126 drivers/staging/rtl8712/rtl871x_security.c

    88	
    89	/*
    90	 * Need to consider the fragment situation
    91	 */
    92	void r8712_wep_encrypt(struct _adapter *padapter, u8 *pxmitframe)
    93	{	/* exclude ICV */
    94		unsigned char	crc[4];
    95		struct arc4_ctx  mycontext;
    96		u32 curfragnum, length, keylength, pki;
    97		u8 *pframe, *payload, *iv;    /*,*wepkey*/
    98		u8 wepkey[16];
    99		struct	pkt_attrib  *pattrib = &((struct xmit_frame *)
   100					       pxmitframe)->attrib;
   101		struct	security_priv *psecuritypriv = &padapter->securitypriv;
   102		struct	xmit_priv *pxmitpriv = &padapter->xmitpriv;
   103	
   104		if (((struct xmit_frame *)pxmitframe)->buf_addr == NULL)
   105			return;
   106		pframe = ((struct xmit_frame *)pxmitframe)->buf_addr + TXDESC_OFFSET;
   107		/*start to encrypt each fragment*/
   108		if ((pattrib->encrypt == _WEP40_) || (pattrib->encrypt == _WEP104_)) {
   109			pki = psecuritypriv->PrivacyKeyIndex;
   110			keylength = psecuritypriv->DefKeylen[pki];
   111			for (curfragnum = 0; curfragnum < pattrib->nr_frags;
   112			     curfragnum++) {
   113				iv = pframe + pattrib->hdrlen;
   114				memcpy(&wepkey[0], iv, 3);
   115				memcpy(&wepkey[3], &psecuritypriv->DefKey[
   116					psecuritypriv->PrivacyKeyIndex].skey[0],
   117					keylength);
   118				payload = pframe + pattrib->iv_len + pattrib->hdrlen;
   119				if ((curfragnum + 1) == pattrib->nr_frags) {
   120					length = pattrib->last_txcmdsz -
   121						pattrib->hdrlen -
   122						pattrib->iv_len -
   123						pattrib->icv_len;
   124					*((__le32 *)crc) = cpu_to_le32(getcrc32(
   125							payload, length));
 > 126					arc4_setkey(&mycontext, wepkey, 3 + keylength);
 > 127					arc4_crypt(&mycontext, payload, payload,
   128						   length);
   129					arc4_crypt(&mycontext, payload + length,
   130						   crc, 4);
   131				} else {
   132					length = pxmitpriv->frag_len -
   133						 pattrib->hdrlen - pattrib->iv_len -
   134						 pattrib->icv_len;
   135					*((__le32 *)crc) = cpu_to_le32(getcrc32(
   136							payload, length));
 > 137					arc4_setkey(&mycontext, wepkey, 3 + keylength);
   138					arc4_crypt(&mycontext, payload, payload,
   139						   length);
   140					arc4_crypt(&mycontext, payload + length,
   141						   crc, 4);
   142					pframe += pxmitpriv->frag_len;
   143					pframe = (u8 *)RND4((addr_t)(pframe));
   144				}
   145			}
   146		}
   147	}
   148	

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