linux-kernel - Re: [PATCH 3/7] drivers/usb/gadget/pch_udc.c: adjust suspicious bit operation

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Date:	Thu, 7 Jun 2012 16:23:18 +0200 (CEST)
From:	Julia Lawall <julia.lawall@...6.fr>
To:	Sergei Shtylyov <sshtylyov@...sta.com>
cc:	Julia Lawall <Julia.Lawall@...6.fr>, Felipe Balbi <balbi@...com>,
	kernel-janitors@...r.kernel.org,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
	joe@...ches.com, Julia Lawall <julia@...u.dk>
Subject: Re: [PATCH 3/7] drivers/usb/gadget/pch_udc.c: adjust suspicious bit
 operation



On Thu, 7 Jun 2012, Sergei Shtylyov wrote:

> Hello.
>
> On 07-06-2012 1:41, Julia Lawall wrote:
>
>> From: Julia Lawall <Julia.Lawall@...6.fr>
>
>> PCH_UDC_DMA_LAST is 0x08000000 so a bit-or with this value always gives a
>> nonzero result.  The test is rewritten as done elsewhere in the same file.
>
>> This problem was found using Coccinelle (http://coccinelle.lip6.fr/).
>
>> Signed-off-by: Julia Lawall<julia@...u.dk>
>
>> ---
>>   drivers/usb/gadget/pch_udc.c |    3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>> 
>> diff --git a/drivers/usb/gadget/pch_udc.c b/drivers/usb/gadget/pch_udc.c
>> index 1cfcc9e..79f7a53 100644
>> --- a/drivers/usb/gadget/pch_udc.c
>> +++ b/drivers/usb/gadget/pch_udc.c
>> @@ -2208,7 +2208,8 @@ static void pch_udc_complete_receiver(struct 
>> pch_udc_ep *ep)
>>   			return;
>>   		}
>>   		if ((td->status&  PCH_UDC_BUFF_STS) == PCH_UDC_BS_DMA_DONE)
>> -			if (td->status | PCH_UDC_DMA_LAST) {
>> +			if ((td_data->status&  PCH_UDC_DMA_LAST)
>> +			    == PCH_UDC_DMA_LAST) {
>
>   But why not simply:
>
> 			if (td_data->status & PCH_UDC_DMA_LAST)
>
> if the constant is single bit anyway? And are you sure about s/td/td_data/?

Oops, thanks for noticing that.  I'll send a corrected version.

thanks,
julia
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