Re: [PATCH 2/8] PM: suspend_block: Add driver to access suspend blockers from user-space

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

On Thursday 29 April 2010, Arve Hjønnevåg wrote:
> 2010/4/28 Rafael J. Wysocki <rjw@sisk.pl>:
> > On Wednesday 28 April 2010, Arve Hjønnevåg wrote:
> >> Add a misc device, "suspend_blocker", that allows user-space processes
> >> to block auto suspend. The device has ioctls to create a suspend_blocker,
> >> and to block and unblock suspend. To delete the suspend_blocker, close
> >> the device.
> >>
> >> Signed-off-by: Arve Hjønnevåg <arve@android.com>
> > ...
> >> +
> >> +#include <linux/fs.h>
> >> +#include <linux/miscdevice.h>
> >> +#include <linux/module.h>
> >> +#include <linux/uaccess.h>
> >> +#include <linux/slab.h>
> >> +#include <linux/suspend_blocker.h>
> >> +#include <linux/suspend_block_dev.h>
> >> +
> >> +enum {
> >> +     DEBUG_FAILURE   = BIT(0),
> >> +};
> >> +static int debug_mask = DEBUG_FAILURE;
> >
> > What's the exact purpose of this?
> 
> To show errors returned to user space. I can turn it off by default if you want.

Not necessarily, but why is it a mask?  It looks like a 0/1 thing would be
sufficient.

BTW, I'd put parens around (debug_mask & DEBUG_FAILURE) for clarity.

Rafael