linux-kernel - Re: [REPORT] Possible unnecessary usages of GFP

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Date:   Mon, 23 Jul 2018 15:19:43 +0800
From:   Jia-Ju Bai <baijiaju1990@...il.com>
To:     Herbert Xu <herbert@...dor.apana.org.au>
Cc:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [REPORT] Possible unnecessary usages of GFP_ATOMIC in
 crypto/ablkcipher.c



On 2018/7/23 14:21, Herbert Xu wrote:
> On Mon, Jul 23, 2018 at 10:39:40AM +0800, Jia-Ju Bai wrote:
>> My tool DCNS reports three unnecessary usages of GFP_ATOMIC in
>> crypto/ablkcipher.c:
>> crypto/ablkcipher.c, 162: kmalloc(GFP_ATOMIC) in ablkcipher_next_slow
>> crypto/ablkcipher.c, 199: kmalloc(GFP_ATOMIC) in ablkcipher_copy_iv
>> crypto/ablkcipher.c, 315: kmalloc(GFP_ATOMIC) in setkey_unaligned
>>
>> I meant to manually check the code, but I find that there are many functions
>> calling ablkcipher_next_slow(),
>> ablkcipher_copy_iv() and setkey_unaligned(), so I am not sure whether the
>> above three reports are true.
>>
>> Could someone help me to validate these reports?
>> Thanks a lot in advance :)
> They must use GFP_ATOMIC because they can be called from softirq
> context, e.g., IPsec.

Okay, thanks for the reply.


Best wishes,
Jia-Ju Bai