linux-kernel - Re: [PATCH 1/2] mm: vmpressure: don't need call kfree if kstrndup fails

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Date:   Wed, 12 Feb 2020 19:14:27 -0800
From:   Yang Shi <yang.shi@...ux.alibaba.com>
To:     David Hildenbrand <david@...hat.com>, akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] mm: vmpressure: don't need call kfree if kstrndup
 fails



On 2/12/20 3:21 AM, David Hildenbrand wrote:
> On 11.02.20 06:24, Yang Shi wrote:
>> When kstrndup fails (returns NULL) there is no memory is allocated by
>> kmalloc, so no need to call kfree().
> "When kstrndup fails, no memory was allocated and we can exit directly."

Thanks for correcting the commit log.

Andrew, do you prefer I send an updated version or you would just update 
the patch in -mm tree?

>
> Reviewed-by: David Hildenbrand <david@...hat.com>
>
>> Signed-off-by: Yang Shi <yang.shi@...ux.alibaba.com>
>> ---
>>   mm/vmpressure.c | 6 ++----
>>   1 file changed, 2 insertions(+), 4 deletions(-)
>>
>> diff --git a/mm/vmpressure.c b/mm/vmpressure.c
>> index 4bac22f..0590f00 100644
>> --- a/mm/vmpressure.c
>> +++ b/mm/vmpressure.c
>> @@ -371,10 +371,8 @@ int vmpressure_register_event(struct mem_cgroup *memcg,
>>   	int ret = 0;
>>   
>>   	spec_orig = spec = kstrndup(args, MAX_VMPRESSURE_ARGS_LEN, GFP_KERNEL);
>> -	if (!spec) {
>> -		ret = -ENOMEM;
>> -		goto out;
>> -	}
>> +	if (!spec)
>> +		return -ENOMEM;
>>   
>>   	/* Find required level */
>>   	token = strsep(&spec, ",");
>>
>