Re: suspend2 merge (was Re: [Suspend2-devel] Re: CFS and suspend2: hang in atomic copy)

Pavel Machek
2007-04-26T10:31:11Z

On Thu 2007-04-26 12:17:12, Johannes Berg wrote:
> On Tue, 2007-04-24 at 23:24 +0200, Pavel Machek wrote:
>
> > I believe uswsusp user/kernel separation is clean enough. Kernel
> > provides "snapshot image" and "resume image". (Thanks go to Rafael for
> > very clean interface).
>
> The interface isn't even 64/32-bit compatible...

Which parts?

read/write on /dev/snapshot looks ok.

ioctl(SNAPSHOT_FREEZE, UNFREEZE, ATOMIC_RESTORE, FREE, FREE_SWAP_PAGE,
SNAPSHOT_S2RAM,
is okay, because it does not pass any data.

ioctl(ATOMIC_SNAPSHOT,
returns 0/1 through pointer. Should be ok. (Maybe we should do

if (!error)
error = put_user(in_suspend, (u32 __user *)arg);

...instead, to make it very explicit?

ioctl(SET_IMAGE_SIZE,
is okay, because it just uses arg directly.

ioctl(PMOPS,
is okay, because it just uses arg directly... and it is in
range 0-3 or something.

ioctl(AVAIL_SWAP,
...hmm, is this the one you are complaining about? It returns
loff_t through a pointer. Maybe there's another interface
that can return available swap, and we should use that, instead?

ioctl(GET_SWAP_PAGE,
returns sector_t through a pointer. NOt sure if that's good
idea, either.

ioctl(SET_SWAP_FILE,
does old_decode_dev(arg). Is that ok?

ioctl(SET_SWAP_AREA,
shares struct resume_swap_area between user and kernel. I
guess that's bad..?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html