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

Arve Hjønnevåg
2010-05-26T23:13:45Z

2010/5/26 Peter Zijlstra <peterz@infradead.org>:
> On Wed, 2010-05-26 at 03:47 -0700, Arve Hjønnevåg wrote:
>> 2010/5/26 Peter Zijlstra <peterz@infradead.org>:
>> > On Fri, 2010-05-21 at 15:46 -0700, Arve Hjønnevåg wrote:
>> >> +To create a suspend blocker from user space, open the suspend_blocker
>> >> special
>> >> +device file:
>> >> +
>> >> +    fd = open("/dev/suspend_blocker", O_RDWR | O_CLOEXEC);
>> >> +
>> >> +then optionally call:
>> >> +
>> >> +    ioctl(fd, SUSPEND_BLOCKER_IOCTL_SET_NAME(strlen(name)), name);
>> >> +
>> >> +To activate the suspend blocker call:
>> >> +
>> >> +    ioctl(fd, SUSPEND_BLOCKER_IOCTL_BLOCK);
>> >> +
>> >> +To deactivate it call:
>> >> +
>> >> +    ioctl(fd, SUSPEND_BLOCKER_IOCTL_UNBLOCK);
>> >> +
>> >> +To destroy the suspend blocker, close the device:
>> >> +
>> >> +    close(fd);
>> >
>> > Urgh, please let the open() be BLOCK, the close() be UNBLOCK, and keep
>> > the SET_NAME thing if you really care.
>> >
>>
>> That would be very inefficient.
>
> How so? Anyway, since you admitted this thing isn't needed at all, I say
> we remove it altogether.
>

I also said it was useful. I don't think we should drop it just
because we can work around its absence.

--
Arve Hjønnevåg