Subject: Re: control tool for amr(4)
To: Manuel Bouyer <firstname.lastname@example.org>
From: Jason Thorpe <email@example.com>
Date: 06/28/2006 12:23:36
On Jun 28, 2006, at 12:06 PM, Manuel Bouyer wrote:
> On Wed, Jun 28, 2006 at 11:51:31AM -0700, Jason Thorpe wrote:
>> On Jun 28, 2006, at 10:50 AM, Manuel Bouyer wrote:
>>>> Only do this if you vslock the buffer!
>>> When calling uvm_vslock(), do we also need to PHOLD() the process ?
>> You only need to PHOLD if you going to do DMA to/from the stack.
> The kernel stack, I guess ?
> So to do dma from/to a user-supplied buffer
> only uvm_vslock() is needed, right ?
Right. Also, make sure you never load in interrupt context (because
you have to lock the user's pmap to extract the physical addresses.)
> Manuel Bouyer <firstname.lastname@example.org>
> NetBSD: 26 ans d'experience feront toujours la difference