linux-kernel - Re: [PATCH v2 2/3] tpm: Provide a function tpm_chip

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Date:   Wed, 3 Feb 2021 03:28:43 +0200
From:   Jarkko Sakkinen <jarkko@...nel.org>
To:     Lino Sanfilippo <LinoSanfilippo@....de>
Cc:     peterhuewe@....de, jgg@...pe.ca, stefanb@...ux.vnet.ibm.com,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        Lino Sanfilippo <l.sanfilippo@...bus.com>
Subject: Re: [PATCH v2 2/3] tpm: Provide a function tpm_chip_free() to free
 tpm chips

On Tue, Feb 02, 2021 at 11:09:02PM +0100, Lino Sanfilippo wrote:
> From: Lino Sanfilippo <l.sanfilippo@...bus.com>
> 
> Provide a function tpm_chip_free() as a counterpart to tpm_chip_alloc().
> The function hides the internals of freeing a struct tpm_chip instance
> by putting the device references which are part of this structure.
> 
> Use the new function at the appropriate places.
> 
> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>

I prefer open coding here.

/Jarkko

> ---
>  drivers/char/tpm/tpm-chip.c       | 16 ++++++++++++++++
>  drivers/char/tpm/tpm.h            |  1 +
>  drivers/char/tpm/tpm_ftpm_tee.c   |  6 ++----
>  drivers/char/tpm/tpm_vtpm_proxy.c |  3 +--
>  4 files changed, 20 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 3ace199..777baae 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -402,6 +402,22 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
>  EXPORT_SYMBOL_GPL(tpm_chip_alloc);
>  
>  /**
> + * tpm_chip_free() - free an instance of struct tpm_chip that has been
> + * allocated with tpm_chip_alloc() before.
> + * @chip: chip to free
> + *
> + * Frees an instance of struct tpm_chip by releasing internal device references.
> + * This function is used to hide the internals needed to free a struct tpm_chip
> + * instance thas has been allocated with tpm_chip_alloc() before.
> + */
> +void tpm_chip_free(struct tpm_chip *chip)
> +{
> +	put_device(&chip->devs);
> +	put_device(&chip->dev);
> +}
> +EXPORT_SYMBOL_GPL(tpm_chip_free);
> +
> +/**
>   * tpmm_chip_alloc() - allocate a new struct tpm_chip instance
>   * @pdev: parent device to which the chip is associated
>   * @ops: struct tpm_class_ops instance
> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> index 947d1db..e6bb6ae 100644
> --- a/drivers/char/tpm/tpm.h
> +++ b/drivers/char/tpm/tpm.h
> @@ -199,6 +199,7 @@ void tpm_put_ops(struct tpm_chip *chip);
>  
>  struct tpm_chip *tpm_chip_alloc(struct device *dev,
>  				const struct tpm_class_ops *ops);
> +void tpm_chip_free(struct tpm_chip *chip);
>  struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
>  				 const struct tpm_class_ops *ops);
>  int tpm_chip_register(struct tpm_chip *chip);
> diff --git a/drivers/char/tpm/tpm_ftpm_tee.c b/drivers/char/tpm/tpm_ftpm_tee.c
> index 82858c2..47ffaae 100644
> --- a/drivers/char/tpm/tpm_ftpm_tee.c
> +++ b/drivers/char/tpm/tpm_ftpm_tee.c
> @@ -285,8 +285,7 @@ static int ftpm_tee_probe(struct device *dev)
>  	return 0;
>  
>  out_chip:
> -	put_device(&pvt_data->chip->dev);
> -	put_device(&pvt_data->chip->devs);
> +	tpm_chip_free(chip);
>  out_chip_alloc:
>  	tee_shm_free(pvt_data->shm);
>  out_shm_alloc:
> @@ -319,8 +318,7 @@ static int ftpm_tee_remove(struct device *dev)
>  	tpm_chip_unregister(pvt_data->chip);
>  
>  	/* frees chip */
> -	put_device(&pvt_data->chip->devs);
> -	put_device(&pvt_data->chip->dev);
> +	tpm_chip_free(pvt_data->chip);
>  
>  	/* Free the shared memory pool */
>  	tee_shm_free(pvt_data->shm);
> diff --git a/drivers/char/tpm/tpm_vtpm_proxy.c b/drivers/char/tpm/tpm_vtpm_proxy.c
> index 97b60f8..f887bb3 100644
> --- a/drivers/char/tpm/tpm_vtpm_proxy.c
> +++ b/drivers/char/tpm/tpm_vtpm_proxy.c
> @@ -520,8 +520,7 @@ static struct proxy_dev *vtpm_proxy_create_proxy_dev(void)
>   */
>  static inline void vtpm_proxy_delete_proxy_dev(struct proxy_dev *proxy_dev)
>  {
> -	put_device(&proxy_dev->chip->devs);
> -	put_device(&proxy_dev->chip->dev); /* frees chip */
> +	tpm_chip_free(proxy_dev->chip);
>  	kfree(proxy_dev);
>  }
>  
> -- 
> 2.7.4
>