Re: [PATCH] staging: rtl8192e: use is_zero_ether_addr() instead ofmemcmp()

From: Eric Dumazet
Date: Thu Aug 23 2012 - 03:54:07 EST


On Thu, 2012-08-23 at 15:19 +0800, Wei Yongjun wrote:
> From: Wei Yongjun <yongjun_wei@xxxxxxxxxxxxxxxxx>
>
> Using is_zero_ether_addr() instead of directly use
> memcmp() to determine if the ethernet address is all
> zeros.
>
> spatch with a semantic match is used to found this problem.
> (http://coccinelle.lip6.fr/)
>
> Signed-off-by: Wei Yongjun <yongjun_wei@xxxxxxxxxxxxxxxxx>
> ---
> drivers/staging/rtl8192e/rtllib_softmac_wx.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/rtl8192e/rtllib_softmac_wx.c b/drivers/staging/rtl8192e/rtllib_softmac_wx.c
> index 1bb6b52..3cedfd9 100644
> --- a/drivers/staging/rtl8192e/rtllib_softmac_wx.c
> +++ b/drivers/staging/rtl8192e/rtllib_softmac_wx.c
> @@ -14,6 +14,8 @@
> */
>
>
> +#include <linux/etherdevice.h>
> +
> #include "rtllib.h"
> #include "dot11d.h"
> /* FIXME: add A freqs */
> @@ -137,7 +139,6 @@ int rtllib_wx_set_wap(struct rtllib_device *ieee,
> {
>
> int ret = 0;
> - u8 zero[] = {0, 0, 0, 0, 0, 0};
> unsigned long flags;
>
> short ifup = ieee->proto_started;
> @@ -157,7 +158,7 @@ int rtllib_wx_set_wap(struct rtllib_device *ieee,
> goto out;
> }
>
> - if (memcmp(temp->sa_data, zero, ETH_ALEN) == 0) {
> + if (is_zero_ether_addr(temp->sa_data)) {
> spin_lock_irqsave(&ieee->lock, flags);
> memcpy(ieee->current_network.bssid, temp->sa_data, ETH_ALEN);

BTW this looks suspicious : Why is it using memcpy() if temp->sa_data is
known to be zero ?

> ieee->wap_set = 0;
> @@ -177,7 +178,7 @@ int rtllib_wx_set_wap(struct rtllib_device *ieee,
>
> ieee->cannot_notify = false;
> memcpy(ieee->current_network.bssid, temp->sa_data, ETH_ALEN);
> - ieee->wap_set = (memcmp(temp->sa_data, zero, ETH_ALEN) != 0);
> + ieee->wap_set = (!is_zero_ether_addr(temp->sa_data));
>
ieee->wap_set = !is_zero_ether_addr(temp->sa_data);

> spin_unlock_irqrestore(&ieee->lock, flags);
>
>
>
> --
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