linux-kernel - Re: [PATCH 3/4] dmaengine: ste_dma40: Remove unneeded ERROR and NULL check in ste

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <d8c8bd7b-f1ac-8dae-9b86-02dc68002aa4@vivo.com>
Date:   Thu, 19 May 2022 14:34:34 +0800
From:   Jiabing Wan <wanjiabing@...o.com>
To:     Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Vinod Koul <vkoul@...nel.org>,
        Orson Zhai <orsonzhai@...il.com>,
        Baolin Wang <baolin.wang7@...il.com>,
        Chunyan Zhang <zhang.lyra@...il.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        dmaengine@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 3/4] dmaengine: ste_dma40: Remove unneeded ERROR and NULL
 check in ste_dma40



On 2022/5/18 15:15, Krzysztof Kozlowski wrote:
> On 16/05/2022 10:41, Wan Jiabing wrote:
>> clk_put() already checks ERROR by using IS_ERR.
>> clk_disable_unprepare() already checks NULL by using IS_ERR_OR_NULL.
>> Remove unneeded NULL check for clk_ret and ERROR check for clk.
>>
>> Signed-off-by: Wan Jiabing <wanjiabing@...o.com>
>> ---
>>   drivers/dma/ste_dma40.c | 10 ++++------
>>   1 file changed, 4 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
>> index e1827393143f..7d1bf4ae4495 100644
>> --- a/drivers/dma/ste_dma40.c
>> +++ b/drivers/dma/ste_dma40.c
>> @@ -3119,7 +3119,7 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
>>   	clk = clk_get(&pdev->dev, NULL);
>>   	if (IS_ERR(clk)) {
>>   		d40_err(&pdev->dev, "No matching clock found\n");
>> -		goto check_prepare_enabled;
>> +		goto disable_unprepare;
> This should be rather return PTR_ERR. No need to jump to labels which
> are not relevant (even if harmless) for this case. It's a confusing code.
OK, I'll fix it.
>>   	}
>>   
>>   	clk_ret = clk_prepare_enable(clk);
>> @@ -3305,12 +3305,10 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
>>   	iounmap(virtbase);
>>    release_region:
>>   	release_mem_region(res->start, resource_size(res));
>> - check_prepare_enabled:
>> -	if (!clk_ret)
>>    disable_unprepare:
>> -		clk_disable_unprepare(clk);
>> -	if (!IS_ERR(clk))
>> -		clk_put(clk);

So this IS_ERR(clk) is also better than WARN_ON_ONCE(IS_ERR(clk)) in 
clk_put().

IS_ERR(clk) before  clk_put(clk) is needed for avoiding the unexpected warning.

>> +	clk_disable_unprepare(clk);
>> +	clk_put(clk);
>> +
>>   	return NULL;
>>   }
>>   
Thanks,
Wan Jiabing