linux-kernel - Re: [PATCH v5 05/19] crypto: introduce crypto wait for async op

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Message-ID: <20170815032303.000042b2@huawei.com>
Date:   Tue, 15 Aug 2017 03:23:03 +0100
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     Gilad Ben-Yossef <gilad@...yossef.com>
CC:     Herbert Xu <herbert@...dor.apana.org.au>,
        "David S. Miller" <davem@...emloft.net>,
        Jonathan Corbet <corbet@....net>,
        David Howells <dhowells@...hat.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Gary Hook <gary.hook@....com>,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Arnaud Ebalard <arno@...isbad.org>,
        Matthias Brugger <matthias.bgg@...il.com>,
        Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>, <dm-devel@...hat.com>,
        Shaohua Li <shli@...nel.org>, Steve French <sfrench@...ba.org>,
        "Theodore Y. Ts'o" <tytso@....edu>,
        "Jaegeuk Kim" <jaegeuk@...nel.org>,
        Mimi Zohar <zohar@...ux.vnet.ibm.com>,
        "Dmitry Kasatkin" <dmitry.kasatkin@...il.com>,
        James Morris <james.l.morris@...cle.com>,
        "Serge E. Hallyn" <serge@...lyn.com>,
        <linux-crypto@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <keyrings@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <linux-raid@...r.kernel.org>,
        <linux-cifs@...r.kernel.org>, <samba-technical@...ts.samba.org>,
        <linux-fscrypt@...r.kernel.org>,
        <linux-ima-devel@...ts.sourceforge.net>,
        <linux-ima-user@...ts.sourceforge.net>,
        <linux-security-module@...r.kernel.org>,
        Eric Biggers <ebiggers3@...il.com>,
        Ofir Drang <ofir.drang@....com>
Subject: Re: [PATCH v5 05/19] crypto: introduce crypto wait for async op

On Mon, 14 Aug 2017 18:21:15 +0300
Gilad Ben-Yossef <gilad@...yossef.com> wrote:

> Invoking a possibly async. crypto op and waiting for completion
> while correctly handling backlog processing is a common task
> in the crypto API implementation and outside users of it.
> 
> This patch adds a generic implementation for doing so in
> preparation for using it across the board instead of hand
> rolled versions.
> 
> Signed-off-by: Gilad Ben-Yossef <gilad@...yossef.com>
> CC: Eric Biggers <ebiggers3@...il.com>

One really trivial point inline I happened to notice.

> ---
>  crypto/api.c           | 13 +++++++++++++
>  include/linux/crypto.h | 41 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 54 insertions(+)
> 
> diff --git a/crypto/api.c b/crypto/api.c
> index 941cd4c..2a2479d 100644
> --- a/crypto/api.c
> +++ b/crypto/api.c
> @@ -24,6 +24,7 @@
>  #include <linux/sched/signal.h>
>  #include <linux/slab.h>
>  #include <linux/string.h>
> +#include <linux/completion.h>
>  #include "internal.h"
>  
>  LIST_HEAD(crypto_alg_list);
> @@ -595,5 +596,17 @@ int crypto_has_alg(const char *name, u32 type, u32 mask)
>  }
>  EXPORT_SYMBOL_GPL(crypto_has_alg);
>  
> +void crypto_req_done(struct crypto_async_request *req, int err)
> +{
> +	struct crypto_wait *wait = req->data;
> +
> +	if (err == -EINPROGRESS)
> +		return;
> +
> +	wait->err = err;
> +	complete(&wait->completion);
> +}
> +EXPORT_SYMBOL_GPL(crypto_req_done);
> +
>  MODULE_DESCRIPTION("Cryptographic core API");
>  MODULE_LICENSE("GPL");
> diff --git a/include/linux/crypto.h b/include/linux/crypto.h
> index 84da997..bb00186 100644
> --- a/include/linux/crypto.h
> +++ b/include/linux/crypto.h
> @@ -24,6 +24,7 @@
>  #include <linux/slab.h>
>  #include <linux/string.h>
>  #include <linux/uaccess.h>
> +#include <linux/completion.h>
>  
>  /*
>   * Autoloaded crypto modules should only use a prefixed name to avoid allowing
> @@ -468,6 +469,45 @@ struct crypto_alg {
>  } CRYPTO_MINALIGN_ATTR;
>  
>  /*
> + * A helper struct for waiting for completion of async crypto ops
> + */
> +struct crypto_wait {
> +	struct completion completion;
> +	int err;
> +};
> +
> +/*
> + * Macro for declaring a crypto op async wait object on stack
> + */
> +#define DECLARE_CRYPTO_WAIT(_wait) \
> +	struct crypto_wait _wait = { \
> +		COMPLETION_INITIALIZER_ONSTACK((_wait).completion), 0 }
> +
> +/*
> + * Async ops completion helper functioons
> + */
> +void crypto_req_done(struct crypto_async_request *req, int err);
> +
> +static inline int crypto_wait_req(int err, struct crypto_wait *wait)
> +{
> +	switch (err) {
> +	case -EINPROGRESS:
> +	case -EBUSY:
> +		wait_for_completion(&wait->completion);
> +		reinit_completion(&wait->completion);
> +		err = wait->err;
> +		break;
> +	};
> +
> +	return err;
> +}
> +
> +static inline void crypto_init_wait(struct crypto_wait *wait)
> +{
> +	init_completion(&wait->completion);
> +}
> +
> +/*
>   * Algorithm registration interface.
>   */
>  int crypto_register_alg(struct crypto_alg *alg);
> @@ -1604,5 +1644,6 @@ static inline int crypto_comp_decompress(struct crypto_comp *tfm,
>  						    src, slen, dst, dlen);
>  }
>  
> +

Trivial observation.  Shouldn't have this bonus blank line inserted here.

>  #endif	/* _LINUX_CRYPTO_H */
>