Re: userspace block driver?

Oliver Neukum
2005-11-09T08:14:16Z

On Wed, 9 Nov 2005, Jeff Garzik wrote:

>
> Has anybody put any thought towards how a userspace block driver would work?
>
> Consider a block device implemented via an SSL network connection. I don't
> want to put SSL in the kernel, which means the only other alternative is to
> pass data to/from a userspace daemon.

I am afraid this is impossible without some heavy infrastructure work.
You will almost inevitably deadlock. Yes, you can mlock() your driver, but
that still will not tell the kernel that GFP_KERNEL must be replaced with
GFP_NOIO if it is triggered by syscalls you are doing.

Regards
Oliver