linux-kernel - Re: [PATCH] mm/ioremap: Use WARN_ONCE instead of printk() + WARN_ON

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Date:   Thu, 31 Oct 2019 19:54:09 +0800
From:   zhong jiang <zhongjiang@...wei.com>
To:     Borislav Petkov <bp@...en8.de>
CC:     <peterz@...radead.org>, <tglx@...utronix.de>, <mingo@...hat.com>,
        <dave.hansen@...ux.intel.com>, <hpa@...or.com>, <x86@...nel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mm/ioremap: Use WARN_ONCE instead of printk() + WARN_ON_ONCE()

On 2019/10/31 19:03, Borislav Petkov wrote:
> On Wed, Oct 30, 2019 at 04:57:18PM +0800, zhong jiang wrote:
>> WARN_ONCE is more clear and simpler. Just replace it.
>>
>> Signed-off-by: zhong jiang <zhongjiang@...wei.com>
>> ---
>>  arch/x86/mm/ioremap.c | 5 ++---
>>  1 file changed, 2 insertions(+), 3 deletions(-)
>>
>> diff --git a/arch/x86/mm/ioremap.c b/arch/x86/mm/ioremap.c
>> index a39dcdb..3b74599 100644
>> --- a/arch/x86/mm/ioremap.c
>> +++ b/arch/x86/mm/ioremap.c
>> @@ -172,9 +172,8 @@ static void __ioremap_check_mem(resource_size_t addr, unsigned long size,
>>  		return NULL;
>>  
>>  	if (!phys_addr_valid(phys_addr)) {
>> -		printk(KERN_WARNING "ioremap: invalid physical address %llx\n",
>> -		       (unsigned long long)phys_addr);
>> -		WARN_ON_ONCE(1);
>> +		WARN_ONCE(1, "ioremap: invalid physical address %llx\n",
>> +			  (unsigned long long)phys_addr);
> Does
> 	WARN_ONCE(!phys_addr_valid(phys_addr),
> 		  "ioremap: invalid physical address %llx\n",
> 		  (unsigned long long)phys_addr);
>
> work too?
>
Look at this again, It should not works. Because that will change the logical.
if phys_addr_valid is false, we should drop out in time.

WARN_ONCE should be just visible for user not should to handle with address.

Thanks,
zhong jiang