linux-kernel - Re: [PATCH 16/18] crypto: talitos - do hw_context DMA mapping outside the requests

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Date:   Mon, 19 Feb 2018 10:14:24 +0100
From:   Christophe LEROY <christophe.leroy@....fr>
To:     Horia Geantă <horia.geanta@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>
Cc:     "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>
Subject: Re: [PATCH 16/18] crypto: talitos - do hw_context DMA mapping outside
 the requests



Le 19/02/2018 à 09:30, Horia Geantă a écrit :
> On 2/19/2018 9:58 AM, Christophe LEROY wrote:
>> Le 18/02/2018 à 18:14, Horia Geantă a écrit :
>>> There is no ahash_exit() callback mirroring ahash_init().
>>>
>>> The clean-up of request ctx should be done in the last states of the hash flows
>>> described here:
>>> https://www.kernel.org/doc/html/latest/crypto/devel-algos.html#cipher-definition-with-struct-shash-alg-and-ahash-alg
>>> for e.g. in the final() callback.
>>
>> Unfortunatly it seems that we can't rely on those finalising functions
>> being called all the time.
>> If you look into test_ahash_jiffies() for instance, in case of error the
>> call of crypto_hash_final() is skipped.
> 
> If test_ahash_jiffies() errors before calling crypto_ahash_final(req), this
> means a previous callback failed.
> Accordingly, DMA unmapping should be performed also on the corresponding errors
> paths in the driver.
> 

And what about ALGIF path from user space ?
What if the user never calls the last sendmsg() which will call 
hash_finup() ?

Christophe