lkml.org 
[lkml]   [2010]   [May]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [BUG] bug when enabling VM DEBUG
From
Date
On Wed, 2010-05-12 at 12:53 +0100, Sebastian Andrzej Siewior wrote:
> * Catalin Marinas | 2010-05-12 12:10:39 [+0100]:
>
> >> > --- a/drivers/ata/libata-sff.c
> >> > +++ b/drivers/ata/libata-sff.c
> >> > @@ -894,7 +894,7 @@ static void ata_pio_sector(struct ata_queued_cmd *qc)
> >> > do_write);
> >> > }
> >> >
> >> > - if (!do_write)
> >> > + if (!do_write&& !PageSlab(page))
> >> > flush_dcache_page(page);
> >>
> >> I would think that check belongs inside flush_dcache_page itself, rather
> >> than forcing every driver to include it..
> >
> >Sebastian (cc'ed) reported this as well for MIPS.
> Thx. The patch above looks what I've sent a while ago. Jeff was going to
> merge it afaik.
>
> >I think it makes sense for this check to be done in the
> >flush_dcache_page() function.
>
> Why should flush_dcache_page() not flush pages you tell it?
> From Documentation/cachetlb.txt:
> | NOTE: This routine need only be called for page cache pages
> | which can potentially ever be mapped into the address
> | space of a user process. So for example, VFS layer code
> | handling vfs symlinks in the page cache need not call
> | this interface at all.
>
> A page from slab or stack is not going to see the sky of user land and
> therefore it should not be fed into flush_dcache_page().

You are right :), so fixing the driver is the best approach.

--
Catalin



\
 
 \ /
  Last update: 2010-05-12 14:27    [W:0.048 / U:1.052 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site