From mboxrd@z Thu Jan  1 00:00:00 1970
From: Zhang Rui <rui.zhang-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH 3/4] fix module autoloading for ACPI enumerated devices
Date: Thu, 16 Jan 2014 16:04:35 +0800
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Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-acpi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
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	rafael.j.wysocki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org,
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To: Mika Westerberg <mika.westerberg-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
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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.

thanks,
rui