linux-kernel - Re: [PATCH 04/29] drivers: base: add notifier for failed driver bind

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Date:	Thu, 21 Aug 2014 21:46:30 +0200
From:	Laurent Pinchart <laurent.pinchart@...asonboard.com>
To:	Marek Szyprowski <m.szyprowski@...sung.com>
Cc:	iommu@...ts.linux-foundation.org,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linaro-mm-sig@...ts.linaro.org, Arnd Bergmann <arnd@...db.de>,
	Shaik Ameer Basha <shaik.ameer@...sung.com>,
	Cho KyongHo <pullip.cho@...sung.com>,
	Joerg Roedel <joro@...tes.org>,
	Thierry Reding <treding@...dia.com>,
	Olof Johansson <olof@...om.net>, Rob Herring <robh@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Inki Dae <inki.dae@...sung.com>,
	Kukjin Kim <kgene.kim@...sung.com>,
	Sylwester Nawrocki <s.nawrocki@...sung.com>,
	Tomasz Figa <tomasz.figa@...il.com>,
	Kyungmin Park <kyungmin.park@...sung.com>
Subject: Re: [PATCH 04/29] drivers: base: add notifier for failed driver bind

Hi Marek,

Thank you for the patch.

On Tuesday 05 August 2014 12:47:32 Marek Szyprowski wrote:
> This patch adds support for getting a notify for failed device driver
> bind, so all the items done in BUS_NOTIFY_BIND_DRIVER event can be
> cleaned if the driver fails to bind.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
> ---
>  drivers/base/dd.c      | 10 +++++++---
>  include/linux/device.h |  4 +++-
>  2 files changed, 10 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index e4ffbcf..541a41f 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -237,10 +237,14 @@ static int driver_sysfs_add(struct device *dev)
>  	return ret;
>  }
> 
> -static void driver_sysfs_remove(struct device *dev)
> +static void driver_sysfs_remove(struct device *dev, int failed)
>  {
>  	struct device_driver *drv = dev->driver;
> 
> +	if (failed && dev->bus)
> +		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> +					     BUS_NOTIFY_DRVBIND_FAILED, dev);

This might be a stupid question, but as you only call driver_sysfs_remove with 
failed set to true in a single location (in the failure path of really_probe), 
how about moving the blocking_notifier_call_chain to that location ? The code 
seems to be a bit out of place here.

> +
>  	if (drv) {
>  		sysfs_remove_link(&drv->p->kobj, kobject_name(&dev->kobj));
>  		sysfs_remove_link(&dev->kobj, "driver");
> @@ -316,7 +320,7 @@ static int really_probe(struct device *dev, struct
> device_driver *drv)
> 
>  probe_failed:
>  	devres_release_all(dev);
> -	driver_sysfs_remove(dev);
> +	driver_sysfs_remove(dev, true);
>  	dev->driver = NULL;
>  	dev_set_drvdata(dev, NULL);
> 
> @@ -509,7 +513,7 @@ static void __device_release_driver(struct device *dev)
>  	if (drv) {
>  		pm_runtime_get_sync(dev);
> 
> -		driver_sysfs_remove(dev);
> +		driver_sysfs_remove(dev, false);
> 
>  		if (dev->bus)
>  			blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
> diff --git a/include/linux/device.h b/include/linux/device.h
> index b387710..92daded 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -176,7 +176,7 @@ extern int bus_register_notifier(struct bus_type *bus,
>  extern int bus_unregister_notifier(struct bus_type *bus,
>  				   struct notifier_block *nb);
> 
> -/* All 4 notifers below get called with the target struct device *
> +/* All 7 notifers below get called with the target struct device *
>   * as an argument. Note that those functions are likely to be called
>   * with the device lock held in the core, so be careful.
>   */
> @@ -189,6 +189,8 @@ extern int bus_unregister_notifier(struct bus_type *bus,
> unbound */
>  #define BUS_NOTIFY_UNBOUND_DRIVER	0x00000006 /* driver is unbound
>  						      from the device */
> +#define BUS_NOTIFY_DRVBIND_FAILED	0x00000007 /* driver failed to bind
> +						      to device */
> 
>  extern struct kset *bus_get_kset(struct bus_type *bus);
>  extern struct klist *bus_get_device_klist(struct bus_type *bus);

-- 
Regards,

Laurent Pinchart

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