lkml.org 
[lkml]   [2015]   [Jan]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] pci-dma: Fix x86 dma_alloc_coherent to fully clear all pages returned
From
Date
On Fri, 2015-01-30 at 11:58 -0800, Greg KH wrote:

>
> Shouldn't this go to stable trees too?
>

Yes. Added the stable tag in updated patch that's resent.

> Also, why is the xhci driver not asking for the memory it is going to
> need? If it wants to use the full page, shouldn't it ask for it?
>

I agree that xhci should have done that, but it didn't. Commit
d92ef66c4f8f ("x86: make dma_alloc_coherent() return zeroed memory
if CMA is enabled") changed the behavior of dma_alloc_coherent
by clearing only the memory being asked for.

So for backward compatibility, clearing the pages
completely to revert to dma_alloc_coherent's original
behavior is probably the safe thing to do.

Thanks.

Tim



\
 
 \ /
  Last update: 2015-01-30 23:21    [W:0.129 / U:4.524 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site