linux-kernel - Re: [PATCH 1/9] crypto: qce: Add core driver implementation

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Message-ID: <20140403233844.GF17066@sonymobile.com>
Date:	Thu, 3 Apr 2014 16:38:44 -0700
From:	Courtney Cavin <courtney.cavin@...ymobile.com>
To:	Stanimir Varbanov <svarbanov@...sol.com>
CC:	Herbert Xu <herbert@...dor.apana.org.au>,
	"David S. Miller" <davem@...emloft.net>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <robh+dt@...nel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
	"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
	"linux-arm-msm@...r.kernel.org" <linux-arm-msm@...r.kernel.org>
Subject: Re: [PATCH 1/9] crypto: qce: Add core driver implementation

On Thu, Apr 03, 2014 at 06:17:58PM +0200, Stanimir Varbanov wrote:
> This adds core driver files. The core part is implementing a
> platform driver probe and remove callbaks, the probe enables
> clocks, checks crypto version, initialize and request dma
> channels, create done tasklet and work queue and finally
> register the algorithms into crypto subsystem.
> 
> Signed-off-by: Stanimir Varbanov <svarbanov@...sol.com>
> ---
>  drivers/crypto/qce/core.c | 333 ++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/crypto/qce/core.h |  69 ++++++++++
>  2 files changed, 402 insertions(+)
>  create mode 100644 drivers/crypto/qce/core.c
>  create mode 100644 drivers/crypto/qce/core.h
> 
> diff --git a/drivers/crypto/qce/core.c b/drivers/crypto/qce/core.c
[...]
> +static struct qce_algo_ops qce_ops[] = {
> +	{
> +		.type = CRYPTO_ALG_TYPE_ABLKCIPHER,
> +		.register_alg = qce_ablkcipher_register,
> +	},
> +	{
> +		.type = CRYPTO_ALG_TYPE_AHASH,
> +		.register_alg = qce_ahash_register,
> +	},
> +};
> +
> +static void qce_unregister_algs(struct qce_device *qce)
> +{
> +	struct qce_alg_template *tmpl, *n;
> +
> +	list_for_each_entry_safe(tmpl, n, &qce->alg_list, entry) {
> +		if (tmpl->crypto_alg_type == CRYPTO_ALG_TYPE_AHASH)
> +			crypto_unregister_ahash(&tmpl->alg.ahash);
> +		else
> +			crypto_unregister_alg(&tmpl->alg.crypto);
> +
> +		list_del(&tmpl->entry);
> +		kfree(tmpl);

I find this whole memory/list management to be very disorganised.
ops->register_alg() is supposed to allocate this item--more precisely,
multiple items--using something that must be able to be kfree'd
directly, register it with the crypto core, and put it on this list
manually.  Here we unregister/remove/free this in the core.  Josh's
recommendation of a unregister_alg callback might help, but it all
remains a bit unclear with register_alg/unregister_alg managing X
algorithms per call. 

Additionally, above you have qce_ops, which clearly defines the
operations for specific algorithms types/groups, which in later patches
are shown to be seperated out into independent implementations.

>From what I can tell, this seems to be a framework with built-in yet
independent crypto implementations which call the crypto API directly.

It would be more logical to me if this was seperated out into a
"library/core" API, with the individual implementations as platform
drivers of their own.  Then they can register with the core, managing
memory how they please.

What am I missing?

> +	}
> +}
> +
> +static int qce_register_algs(struct qce_device *qce)
> +{
> +	struct qce_algo_ops *ops;
> +	int i, rc = -ENODEV;
> +
> +	for (i = 0; i < ARRAY_SIZE(qce_ops); i++) {
> +		ops = &qce_ops[i];
> +		ops->async_req_queue = qce_async_request_queue;
> +		ops->async_req_done = qce_async_request_done;
> +		rc = ops->register_alg(qce, ops);
> +		if (rc)
> +			break;
> +	}
> +
> +	if (rc)
> +		qce_unregister_algs(qce);
> +
> +	return rc;
> +}

-Courtney
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