Re: [PATCH] PM: prevent runtime_resume from racing with probe

["Rafael J. Wysocki" <rjw@sisk.pl>]

On Friday, July 01, 2011, Alan Stern wrote:
> This patch (as1475) adds device_lock() and device_unlock() calls to
> the store methods for the power/control and power/autosuspend_delay_ms
> sysfs attribute files.  We don't want badly timed writes to these
> files to cause runtime_resume callbacks to occur while a driver is
> being probed for a device.
> 
> Signed-off-by: Alan Stern <stern@rowland.harvard.edu>

Applied to suspend-2.6/linux-next.

Thanks,
Rafael


> ---
> 
>  drivers/base/power/sysfs.c |    6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> Index: usb-3.0/drivers/base/power/sysfs.c
> ===================================================================
> --- usb-3.0.orig/drivers/base/power/sysfs.c
> +++ usb-3.0/drivers/base/power/sysfs.c
> @@ -116,12 +116,14 @@ static ssize_t control_store(struct devi
>  	cp = memchr(buf, '\n', n);
>  	if (cp)
>  		len = cp - buf;
> +	device_lock(dev);
>  	if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
>  		pm_runtime_allow(dev);
>  	else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0)
>  		pm_runtime_forbid(dev);
>  	else
> -		return -EINVAL;
> +		n = -EINVAL;
> +	device_unlock(dev);
>  	return n;
>  }
>  
> @@ -205,7 +207,9 @@ static ssize_t autosuspend_delay_ms_stor
>  	if (strict_strtol(buf, 10, &delay) != 0 || delay != (int) delay)
>  		return -EINVAL;
>  
> +	device_lock(dev);
>  	pm_runtime_set_autosuspend_delay(dev, delay);
> +	device_unlock(dev);
>  	return n;
>  }
>  
> 
> 
>