netdev - Re: [PATCH][next] drivers: net: xgene: remove redundant assignment to variable offset

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Message-ID: <1b4f32d0-a203-4c97-94e1-93ec40364c3c@linux.dev>
Date: Thu, 8 Feb 2024 10:07:27 -0500
From: Vadim Fedorenko <vadim.fedorenko@...ux.dev>
To: Dan Carpenter <dan.carpenter@...aro.org>
Cc: Colin Ian King <colin.i.king@...il.com>,
 Iyappan Subramanian <iyappan@...amperecomputing.com>,
 Keyur Chudgar <keyur@...amperecomputing.com>,
 Quan Nguyen <quan@...amperecomputing.com>,
 "David S . Miller" <davem@...emloft.net>, Eric Dumazet
 <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, netdev@...r.kernel.org,
 kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] drivers: net: xgene: remove redundant assignment to
 variable offset

On 08/02/2024 13:40, Dan Carpenter wrote:
> On Thu, Feb 08, 2024 at 12:39:24PM +0000, Vadim Fedorenko wrote:
>> On 08.02.2024 12:20, Colin Ian King wrote:
>>> The variable offset is being initialized with a value that is never
>>> read, it is being re-assigned later on in either path of an if
>>> statement before being used. The initialization is redundant and
>>> can be removed.
>>>
>>> Cleans up clang scan build warning:
>>> drivers/net/ethernet/apm/xgene/xgene_enet_cle.c:736:2: warning: Value
>>> stored to 'offset' is never read [deadcode.DeadStores]
>>>
>>> Signed-off-by: Colin Ian King <colin.i.king@...il.com>
>>> ---
>>>    drivers/net/ethernet/apm/xgene/xgene_enet_cle.c | 1 -
>>>    1 file changed, 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c b/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c
>>> index de5464322311..8f104642897b 100644
>>> --- a/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c
>>> +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c
>>> @@ -733,7 +733,6 @@ static int xgene_cle_setup_rss(struct xgene_enet_pdata *pdata)
>>>    	u32 offset, val = 0;
>>>    	int i, ret = 0;
>>> -	offset = CLE_PORT_OFFSET;
>>>    	for (i = 0; i < cle->parsers; i++) {
>>>    		if (cle->active_parser != PARSER_ALL)
>>>    			offset = cle->active_parser * CLE_PORT_OFFSET;
>>
>> It looks like more refactoring can be done here.
>> "if (cle->active_parser != PARSER_ALL)" is static, no need to check it inside
>> the loop.
>>
> 
> You still need to check...  I don't really think it's an improvement.
> 
> regards,
> dan carpenter
> 
> diff --git a/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c b/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c
> index de5464322311..61e31cc55771 100644
> --- a/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c
> +++ b/drivers/net/ethernet/apm/xgene/xgene_enet_cle.c
> @@ -733,11 +733,11 @@ static int xgene_cle_setup_rss(struct xgene_enet_pdata *pdata)
>   	u32 offset, val = 0;
>   	int i, ret = 0;
>   
> -	offset = CLE_PORT_OFFSET;
> +	if (cle->active_parser != PARSER_ALL)
> +		offset = cle->active_parser * CLE_PORT_OFFSET;
> +

I think we can add "else" here and avoid the loop in case of != 
PARSER_ALL and avoid "if" in the loop, wdyt?

>   	for (i = 0; i < cle->parsers; i++) {
> -		if (cle->active_parser != PARSER_ALL)
> -			offset = cle->active_parser * CLE_PORT_OFFSET;
> -		else
> +		if (cle->active_parser == PARSER_ALL)
>   			offset = i * CLE_PORT_OFFSET;
>   
>   		/* enable RSS */