linux-kernel - Re: [PATCH] ath10k: fix the status check and wrong return

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Date:   Tue, 18 Aug 2020 09:42:03 +0800
From:   Tang Bin <tangbin@...s.chinamobile.com>
To:     Kalle Valo <kvalo@...eaurora.org>
Cc:     davem@...emloft.net, netdev@...r.kernel.org,
        linux-wireless@...r.kernel.org, linux-kernel@...r.kernel.org,
        ath10k@...ts.infradead.org
Subject: Re: [PATCH] ath10k: fix the status check and wrong return

Hi Kalle：

在 2020/8/17 22:26, Kalle Valo 写道:
>> In the function ath10k_ahb_clock_init(), devm_clk_get() doesn't
>> return NULL. Thus use IS_ERR() and PTR_ERR() to validate
>> the returned value instead of IS_ERR_OR_NULL().
> Why? What's the benefit of this patch? Or what harm does
> IS_ERR_OR_NULL() create?

Thanks for you reply, the benefit of this patch is simplify the code, 
because in

this function, I don't think the situation of 'devm_clk_get() return 
NULL' exists.

So please think about it, thanks.


Tang Bin

>
>> Signed-off-by: Zhang Shengju <zhangshengju@...s.chinamobile.com>
>> Signed-off-by: Tang Bin <tangbin@...s.chinamobile.com>
>> ---
>>   drivers/net/wireless/ath/ath10k/ahb.c | 12 ++++++------
>>   1 file changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath10k/ahb.c b/drivers/net/wireless/ath/ath10k/ahb.c
>> index ed87bc00f..ea669af6a 100644
>> --- a/drivers/net/wireless/ath/ath10k/ahb.c
>> +++ b/drivers/net/wireless/ath/ath10k/ahb.c
>> @@ -87,24 +87,24 @@ static int ath10k_ahb_clock_init(struct ath10k *ar)
>>   	dev = &ar_ahb->pdev->dev;
>>   
>>   	ar_ahb->cmd_clk = devm_clk_get(dev, "wifi_wcss_cmd");
>> -	if (IS_ERR_OR_NULL(ar_ahb->cmd_clk)) {
>> +	if (IS_ERR(ar_ahb->cmd_clk)) {
>>   		ath10k_err(ar, "failed to get cmd clk: %ld\n",
>>   			   PTR_ERR(ar_ahb->cmd_clk));
>> -		return ar_ahb->cmd_clk ? PTR_ERR(ar_ahb->cmd_clk) : -ENODEV;
>> +		return PTR_ERR(ar_ahb->cmd_clk);
>>   	}
> devm_clk_get() can return NULL if CONFIG_HAVE_CLK is disabled:
>
> static inline struct clk *devm_clk_get(struct device *dev, const char *id)
> {
> 	return NULL;
> }
>