From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752461AbbJJRe7 (ORCPT ); Sat, 10 Oct 2015 13:34:59 -0400 Received: from mail-ob0-f169.google.com ([209.85.214.169]:34001 "EHLO mail-ob0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752039AbbJJRe6 (ORCPT ); Sat, 10 Oct 2015 13:34:58 -0400 Subject: Re: [PATCH 2/4] Staging: rtl8712: Use ether_addr_equal() over memcmp() To: Punit Vara References: <1444496322-3648-1-git-send-email-punitvara@gmail.com> <1444496322-3648-3-git-send-email-punitvara@gmail.com> Cc: gregkh@linuxfoundation.org, stillcompiling@gmail.com, sudipm.mukherjee@gmail.com, dan.carpenter@oracle.com, dogukan.ergun@gmail.com, Julia.Lawall@lip6.fr, devel@driverdev.osuosl.org, linux-kernel@vger.kernel.org From: Larry Finger Message-ID: <56194C3E.2000905@lwfinger.net> Date: Sat, 10 Oct 2015 12:34:54 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <1444496322-3648-3-git-send-email-punitvara@gmail.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/10/2015 11:58 AM, Punit Vara wrote: > This patch is to the rtl871x_ioctl_linux.c file that fixes up following > warning reported by checkpatch.pl : > > -Prefer ether_addr_equal() or ether_addr_equal_unaligned() over memcmp() > > bssid has datatype u8 and pnetwork->network.MacAddress has data type > unsigned char. > > Signed-off-by: Punit Vara > --- > drivers/staging/rtl8712/rtl871x_ioctl_linux.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c > index 2ba055d..1c9092e 100644 > --- a/drivers/staging/rtl8712/rtl871x_ioctl_linux.c > +++ b/drivers/staging/rtl8712/rtl871x_ioctl_linux.c > @@ -2007,7 +2007,7 @@ static int r871x_get_ap_info(struct net_device *dev, > return -EINVAL; > } > netdev_info(dev, "r8712u: BSSID:%pM\n", bssid); > - if (!memcmp(bssid, pnetwork->network.MacAddress, ETH_ALEN)) { > + if (!ether_addr_equal(bssid, pnetwork->network)) { > /* BSSID match, then check if supporting wpa/wpa2 */ > pbuf = r8712_get_wpa_ie(&pnetwork->network.IEs[12], > &wpa_ielen, pnetwork->network.IELength-12); > The types of the variables are not what is important - it is the alignment! I suggest that you read the definition of ether_addr_equal() and consider what happens if either of the two addresses is not aligned to u16! You also have a logic error. Routine memcmp() returns zero when the two arguments are equal. Thus !memcmp() will be true when they are equal. Routine ether_addr_equal() returns true when the arguments are equal. Whenever !memcmp() is correct and the arguments are aligned, then you need to replace it with ether_addr_equal(). The checkpatch script is a good tool for locating things to be changed; however, if the change is other than cosmetic, you *MUST THINK* about what is happening. Yes, rtl8712 is ugly code, but it works. Please do not break it. NACK. Larry