Date: Wed, 16 Nov 2005 19:07:16 +0000
From: Pavel Machek <pavel@suse.cz>
To: Stefan Rompf <stefan@loplof.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [RFC] userland swsusp
Message-ID: <20051116190715.GF2193@spitz.ucw.cz>
References: <200511161700.27239.stefan@loplof.de>
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Hi!

> > This is prototype of userland swsusp. I'd like kernel parts to go in,
> > probably for 2.6.16. Now, I'm not sure about the interface, ioctls are
> > slightly ugly, OTOH it would be probably overkill to introduce
> > syscalls just for this. (I'll need to add an ioctl for freeing memory
> > in future).
> 
> I'm curious on the restrictions the userspace part would have to accept.
> Can /usr/swsusp.c write to a file? Currently, you allow it, but I doubt

No. Writing to file would trash the filesystem. But you can bmap the file,
then write to the block device.

> whether it would be wise to write to a file after you've snapshotted
> kernel's filesystem state. OTOH, I don't want to reserve a partition just
> for the image. Can userspace allocate memory after ioctl(SYS_FREEZE)?

Better avoid memory allocation.

> I have userspace supported encryption of the image in mind.

Yes, that should be feasible. 
							Pavel
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