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

[Pavel Machek]

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
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