linux-kernel - Re: [PATCH v2 09/10] crypto: caam - add crypto

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Date:   Mon, 13 Jan 2020 13:06:21 +0000
From:   Iuliana Prodan <iuliana.prodan@....com>
To:     Horia Geanta <horia.geanta@....com>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Aymen Sghaier <aymen.sghaier@....com>
CC:     "David S. Miller" <davem@...emloft.net>,
        "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>
Subject: Re: [PATCH v2 09/10] crypto: caam - add crypto_engine support for RSA
 algorithms

On 1/13/2020 2:21 PM, Horia Geanta wrote:
> On 1/13/2020 11:48 AM, Iuliana Prodan wrote:
>> On 1/10/2020 10:46 AM, Horia Geanta wrote:
>>> On 1/3/2020 3:03 AM, Iuliana Prodan wrote:
>>>> +static int akcipher_enqueue_req(struct device *jrdev, u32 *desc,
>>>> +				void (*cbk)(struct device *jrdev, u32 *desc,
>>>> +					    u32 err, void *context),
>>>> +				struct akcipher_request *req,
>>>> +				struct rsa_edesc *edesc)
>>>> +{
>>>> +	struct caam_drv_private_jr *jrpriv = dev_get_drvdata(jrdev);
>>>> +	struct crypto_akcipher *tfm = crypto_akcipher_reqtfm(req);
>>>> +	struct caam_rsa_ctx *ctx = akcipher_tfm_ctx(tfm);
>>>> +	struct caam_rsa_key *key = &ctx->key;
>>>> +	int ret;
>>>> +
>>>> +	if (req->base.flags & CRYPTO_TFM_REQ_MAY_BACKLOG)
>>>> +		return crypto_transfer_akcipher_request_to_engine(jrpriv->engine,
>>>> +								  req);
>>> Resource leak in case transfer fails.
>>>
>>>> +	else
>>>> +		ret = caam_jr_enqueue(jrdev, desc, cbk, &edesc->jrentry);
>>> What's the problem with transferring all requests to crypto engine?
>>>
>> I'll address all your comments in v3.
>>
>> Regarding the transfer request to crypto-engine: if sending all requests
>> to crypto-engine, multibuffer tests, for non-backlogging requests fail
>> after only 10 requests, since crypto-engine queue has 10 entries.
>> Here's an example:
>> root@...6qpdlsolox:~# insmod tcrypt.ko mode=422 num_mb=1024
>> insmod: ERROR: could not insert module tcrypt.ko: Resource temporarily
>> unavailable
>> root@...6qpdlsolox:~#
>> root@...6qpdlsolox:~# dmesg
>> ...
>> testing speed of multibuffer sha1 (sha1-caam)
>> tcrypt: test  0 (   16 byte blocks,   16 bytes per update,   1 updates):
>> tcrypt: concurrent request 11 error -28
>> tcrypt: concurrent request 13 error -28
>> tcrypt: concurrent request 14 error -28
>> tcrypt: concurrent request 16 error -28
>> tcrypt: concurrent request 18 error -28
>> tcrypt: concurrent request 20 error -28
>> tcrypt: concurrent request 22 error -28
>> tcrypt: concurrent request 24 error -28
>> tcrypt: concurrent request 26 error -28
>> tcrypt: concurrent request 28 error -28
>> tcrypt: concurrent request 30 error -28
>> tcrypt: concurrent request 32 error -28
>> tcrypt: concurrent request 34 error -28
>>
>> tcrypt: concurrent request 1020 error -28
>> tcrypt: concurrent request 1022 error -28
>> tcrypt: At least one hashing failed ret=-28
>> root@...6qpdlsolox:~#
>>
>> If sending just the backlog request to crypto-engine, and non-blocking
>> directly to CAAM, these tests have a better chance to pass since JR has
>> 1024 entries.
>>
>> Will need to work/update crypto-engine: set queue length when initialize
>> crypto-engine, and remove serialization of requests in crypto-engine.
>> But, until then, I would like to have a backlogging solution in CAAM driver.
>>
> My point is you need to add details about the current limitations
> in the commit message (even in the source code, it wouldn't hurt),
> justifying the choice of not using crypto engine for all requests.
> 
Yes, I understand your point and, as I mentioned above, I'll address all 
comments, from all patches, in v3:
- update commit messages;
- handle resource leak in case of crypto-engine transfer;
- remove unnecessary variables, in some structs;
- will remove patch #6.

Iulia