Message-ID: <1389923766.5918.1.camel@rzhang1-mobl4>
Subject: Re: [PATCH 3/4] fix module autoloading for ACPI enumerated devices
From: Zhang Rui <rui.zhang@intel.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: grant.likely@linaro.org, Mika Westerberg <mika.westerberg@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        linux-i2c@vger.kernel.org, linux-spi@vger.kernel.org,
        wsa@the-dreams.de, broonie@linaro.org, gregkh@linuxfoundation.org,
        rob.herring@calxeda.com, jarkko.nikula@linux.intel.com
Date: Fri, 17 Jan 2014 09:56:06 +0800
In-Reply-To: <3559262.qTvGllE4Ix@vostro.rjw.lan>
References: <1389689198-2641-1-git-send-email-rui.zhang@intel.com>
	 <20140115150834.GX2494@intel.com> <1389859475.3010.5.camel@rzhang1-mobl4>
	 <3559262.qTvGllE4Ix@vostro.rjw.lan>
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Sender: linux-kernel-owner@vger.kernel.org

On Fri, 2014-01-17 at 02:28 +0100, Rafael J. Wysocki wrote:
> On Thursday, January 16, 2014 04:04:35 PM Zhang Rui wrote:
> > On Wed, 2014-01-15 at 17:08 +0200, Mika Westerberg wrote:
> > > On Tue, Jan 14, 2014 at 04:46:37PM +0800, Zhang Rui wrote:
> > > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> > > > index 3a94b79..2f4aea2 100644
> > > > --- a/drivers/base/platform.c
> > > > +++ b/drivers/base/platform.c
> > > > @@ -677,7 +677,13 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *a,
> > > >  			     char *buf)
> > > >  {
> > > >  	struct platform_device	*pdev = to_platform_device(dev);
> > > > -	int len = snprintf(buf, PAGE_SIZE, "platform:%s\n", pdev->name);
> > > > +	int len;
> > > > +
> > > > +	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
> > > 
> > > Here you have PAGE_SIZE -1...
> > > 
> > > > +	if (len != -ENODEV)
> > > > +		return len;
> > > > +
> > > > +	len = snprintf(buf, PAGE_SIZE, "platform:%s\n", pdev->name);
> > > >  
> > > >  	return (len >= PAGE_SIZE) ? (PAGE_SIZE - 1) : len;
> > > >  }
> > > > @@ -699,6 +705,10 @@ static int platform_uevent(struct device *dev, struct kobj_uevent_env *env)
> > > >  	if (rc != -ENODEV)
> > > >  		return rc;
> > > >  
> > > > +	rc = acpi_device_uevent_modalias(dev, env);
> > > > +	if (rc != -ENODEV)
> > > > +		return rc;
> > > > +
> > > >  	add_uevent_var(env, "MODALIAS=%s%s", PLATFORM_MODULE_PREFIX,
> > > >  			pdev->name);
> > > >  	return 0;
> > > > diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> > > > index d74c0b3..c4c5588 100644
> > > > --- a/drivers/i2c/i2c-core.c
> > > > +++ b/drivers/i2c/i2c-core.c
> > > > @@ -104,6 +104,11 @@ static int i2c_device_match(struct device *dev, struct device_driver *drv)
> > > >  static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
> > > >  {
> > > >  	struct i2c_client	*client = to_i2c_client(dev);
> > > > +	int rc;
> > > > +
> > > > +	rc = acpi_device_uevent_modalias(dev, env);
> > > > +	if (rc != -ENODEV)
> > > > +		return rc;
> > > >  
> > > >  	if (add_uevent_var(env, "MODALIAS=%s%s",
> > > >  			   I2C_MODULE_PREFIX, client->name))
> > > > @@ -409,6 +414,12 @@ static ssize_t
> > > >  show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
> > > >  {
> > > >  	struct i2c_client *client = to_i2c_client(dev);
> > > > +	int len;
> > > > +
> > > > +	len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
> > > 
> > > and here
> > > 
> > > > +	if (len != -ENODEV)
> > > > +		return len;
> > > > +
> > > >  	return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
> > > >  }
> > > >  
> > > > diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
> > > > index 349ebba..ab70eda 100644
> > > > --- a/drivers/spi/spi.c
> > > > +++ b/drivers/spi/spi.c
> > > > @@ -58,6 +58,11 @@ static ssize_t
> > > >  modalias_show(struct device *dev, struct device_attribute *a, char *buf)
> > > >  {
> > > >  	const struct spi_device	*spi = to_spi_device(dev);
> > > > +	int len;
> > > > +
> > > > +	len = acpi_device_modalias(dev, buf, PAGE_SIZE);
> > > 
> > > but here it is PAGE_SIZE.
> > > 
> > good catch.
> > 
> > > Perhaps it should be PAGE_SIZE in all sites?
> > 
> > dev_attr_show() will give a warning message if modalias_show() returns
> > PAGE_SIZE, thus I'd prefer to use PAGE_SIZE - 1 for all sites.
> 
> So I changed the PAGE_SIZE to PAGE_SIZE - 1 in the last instance and queued
> up the whole series for 3.14 in linux-pm.git/linux-next.  Please have a look
> at that and let me know if there's anything wrong with it.
> 
the change looks okay to me.

thanks,
rui
> Thanks!
> 


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