linux-kernel - NACK: [PATCH] x86/platform/olpc: remove duplicated check on node == -1

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Message-ID: <d0d75e91-9dce-3d36-6a29-c58ae81b9a9f@canonical.com>
Date:   Sun, 9 Dec 2018 17:30:23 +0000
From:   Colin Ian King <colin.king@...onical.com>
To:     Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>, x86@...nel.org,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: NACK: [PATCH] x86/platform/olpc: remove duplicated check on node ==
 -1

On 09/12/2018 17:13, Christophe JAILLET wrote:
> Le 09/12/2018 à 16:01, Colin King a écrit :
>> From: Colin Ian King <colin.king@...onical.com>
>>
>> Currently the node == -1 check is being performed twice, the
>> second check is redundant and can be removed.  Fix this by
>> removing the redundant second check and moving the first check
>> into a combined check with the result from the olpc_ofw call.
>>
>> Detected by cppcheck:
>> Identical condition '(s32)node==-1', second condition is always false
>>
>> Signed-off-by: Colin Ian King <colin.king@...onical.com>
>> ---
>>   arch/x86/platform/olpc/olpc_dt.c | 5 +----
>>   1 file changed, 1 insertion(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/platform/olpc/olpc_dt.c
>> b/arch/x86/platform/olpc/olpc_dt.c
>> index b4ab779f1d47..658363ec3ff3 100644
>> --- a/arch/x86/platform/olpc/olpc_dt.c
>> +++ b/arch/x86/platform/olpc/olpc_dt.c
>> @@ -28,10 +28,7 @@ static phandle __init olpc_dt_getsibling(phandle node)
>>       const void *args[] = { (void *)node };
>>       void *res[] = { &node };
>>   -    if ((s32)node == -1)
>> -        return 0;
>> -
>> -    if (olpc_ofw("peer", args, res) || (s32)node == -1)
>> +    if (((s32)node == -1) || olpc_ofw("peer", args, res))
>>           return 0;
>>         return node;
> 
> 'res' is { &node }
> 
> Could 'node' be modified by 'olpc_ofw(..., res)' and set to -1?
> 
> In other words, I'm not sure that the 2nd check is a redundant here.

Quite right. My mistake. Urgh.

> 
> Just my 2c,
> 
> CJ
>