linux-kernel - Re: [PATCH v2] Do not disable driver and bus shutdown hook when class shutdown hook is set.

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Date:   Sat, 19 Aug 2017 15:03:53 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Michal Suchanek <msuchanek@...e.de>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Huewe <peterhuewe@....de>,
        Marcel Selhorst <tpmdd@...horst.net>,
        Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
        "David S. Miller" <davem@...emloft.net>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Phil Sutter <phil@....cc>, Josh Zimmerman <joshz@...gle.com>,
        Madalin Bucur <madalin.bucur@....com>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Ludovic Desroches <ludovic.desroches@...inux.fr>,
        linux-kernel@...r.kernel.org, tpmdd-devel@...ts.sourceforge.net
Subject: Re: [PATCH v2] Do not disable driver and bus shutdown hook when
 class shutdown hook is set.

On Fri, Aug 11, 2017 at 03:44:43PM +0200, Michal Suchanek wrote:
> As seen from the implementation of the single class shutdown hook this
> is not very sound design.
> 
> Rename the class shutdown hook to shutdown_pre to make it clear it runs
> before the driver shutdown hook.
> 
> Signed-off-by: Michal Suchanek <msuchanek@...e.de>

I already gave this reviewed-by but cannot apply it because there's no
ack from device maintainers yet.

/Jarkko

> ---
> v2: rename class shutdown member to shutdown_pre
> ---
>  drivers/base/core.c         |  9 +++++----
>  drivers/char/tpm/tpm-chip.c | 11 ++---------
>  include/linux/device.h      |  4 ++--
>  3 files changed, 9 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 755451f684bc..13e7c41fd417 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -2664,11 +2664,12 @@ void device_shutdown(void)
>  		pm_runtime_get_noresume(dev);
>  		pm_runtime_barrier(dev);
>  
> -		if (dev->class && dev->class->shutdown) {
> +		if (dev->class && dev->class->shutdown_pre) {
>  			if (initcall_debug)
> -				dev_info(dev, "shutdown\n");
> -			dev->class->shutdown(dev);
> -		} else if (dev->bus && dev->bus->shutdown) {
> +				dev_info(dev, "shutdown_pre\n");
> +			dev->class->shutdown_pre(dev);
> +		}
> +		if (dev->bus && dev->bus->shutdown) {
>  			if (initcall_debug)
>  				dev_info(dev, "shutdown\n");
>  			dev->bus->shutdown(dev);
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 67ec9d3d04f5..0eca20c5a80c 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -164,14 +164,7 @@ static int tpm_class_shutdown(struct device *dev)
>  		chip->ops = NULL;
>  		up_write(&chip->ops_sem);
>  	}
> -	/* Allow bus- and device-specific code to run. Note: since chip->ops
> -	 * is NULL, more-specific shutdown code will not be able to issue TPM
> -	 * commands.
> -	 */
> -	if (dev->bus && dev->bus->shutdown)
> -		dev->bus->shutdown(dev);
> -	else if (dev->driver && dev->driver->shutdown)
> -		dev->driver->shutdown(dev);
> +
>  	return 0;
>  }
>  
> @@ -214,7 +207,7 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
>  	device_initialize(&chip->devs);
>  
>  	chip->dev.class = tpm_class;
> -	chip->dev.class->shutdown = tpm_class_shutdown;
> +	chip->dev.class->shutdown_pre = tpm_class_shutdown;
>  	chip->dev.release = tpm_dev_release;
>  	chip->dev.parent = pdev;
>  	chip->dev.groups = chip->groups;
> diff --git a/include/linux/device.h b/include/linux/device.h
> index beabdbc08420..649b1b72c76a 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -375,7 +375,7 @@ int subsys_virtual_register(struct bus_type *subsys,
>   * @suspend:	Used to put the device to sleep mode, usually to a low power
>   *		state.
>   * @resume:	Used to bring the device from the sleep mode.
> - * @shutdown:	Called at shut-down time to quiesce the device.
> + * @shutdown_pre: Called at shut-down time before driver shutdown.
>   * @ns_type:	Callbacks so sysfs can detemine namespaces.
>   * @namespace:	Namespace of the device belongs to this class.
>   * @pm:		The default device power management operations of this class.
> @@ -404,7 +404,7 @@ struct class {
>  
>  	int (*suspend)(struct device *dev, pm_message_t state);
>  	int (*resume)(struct device *dev);
> -	int (*shutdown)(struct device *dev);
> +	int (*shutdown_pre)(struct device *dev);
>  
>  	const struct kobj_ns_type_operations *ns_type;
>  	const void *(*namespace)(struct device *dev);
> -- 
> 2.10.2
>