linux-kernel - Re: [PATCH 07/12] crypto: caam - use devres to de-initialize the RNG

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Date:   Mon, 9 Sep 2019 15:39:26 +0000
From:   Horia Geanta <horia.geanta@....com>
To:     Andrey Smirnov <andrew.smirnov@...il.com>,
        "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>
CC:     Chris Healy <cphealy@...il.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Herbert Xu <herbert@...dor.apana.org.au>,
        Iuliana Prodan <iuliana.prodan@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 07/12] crypto: caam - use devres to de-initialize the RNG

On 9/4/2019 5:35 AM, Andrey Smirnov wrote:
> Use devres to de-initialize the RNG and drop explicit de-initialization
> code in caam_remove().
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@...il.com>
> Cc: Chris Healy <cphealy@...il.com>
> Cc: Lucas Stach <l.stach@...gutronix.de>
> Cc: Horia Geantă <horia.geanta@....com>
> Cc: Herbert Xu <herbert@...dor.apana.org.au>
> Cc: Iuliana Prodan <iuliana.prodan@....com>
> Cc: linux-crypto@...r.kernel.org
> Cc: linux-kernel@...r.kernel.org
> ---
>  drivers/crypto/caam/ctrl.c | 129 ++++++++++++++++++++-----------------
>  1 file changed, 70 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/crypto/caam/ctrl.c b/drivers/crypto/caam/ctrl.c
> index 254963498abc..25f8f76551a5 100644
> --- a/drivers/crypto/caam/ctrl.c
> +++ b/drivers/crypto/caam/ctrl.c
> @@ -175,6 +175,73 @@ static inline int run_descriptor_deco0(struct device *ctrldev, u32 *desc,
>  	return 0;
>  }
>  
> +/*
> + * deinstantiate_rng - builds and executes a descriptor on DECO0,
> + *		       which deinitializes the RNG block.
> + * @ctrldev - pointer to device
> + * @state_handle_mask - bitmask containing the instantiation status
> + *			for the RNG4 state handles which exist in
> + *			the RNG4 block: 1 if it's been instantiated
> + *
> + * Return: - 0 if no error occurred
> + *	   - -ENOMEM if there isn't enough memory to allocate the descriptor
> + *	   - -ENODEV if DECO0 couldn't be acquired
> + *	   - -EAGAIN if an error occurred when executing the descriptor
> + */
> +static int deinstantiate_rng(struct device *ctrldev, int state_handle_mask)
I assume this function is not modified, only moved further up
to avoid forward declaration.

> +	if (!ret) {
> +		ret = devm_add_action_or_reset(ctrldev, devm_deinstantiate_rng,
> +					       ctrldev);
>  	}
Braces not needed.

Is there any guidance wrt. when *not* to use devres?

Horia