[PATCH] Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask

[PATCH] Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask

[Patrick Colp]

# HG changeset patch
# User Patrick Colp <Patrick.Colp@citrix.com>
# Date 1242295647 -3600
# Node ID c5098f5c5caf4174bd2e46d49d7b65109203f7c5
# Parent  2522cc95efd2f3fadf7342d18fe86e8f37f89c2a
Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask.

Signed-off-by: Patrick Colp <Patrick.Colp@citrix.com>

diff -r 2522cc95efd2 -r c5098f5c5caf xen/arch/x86/mm.c
--- a/xen/arch/x86/mm.c	Mon May 11 13:52:04 2009 +0100
+++ b/xen/arch/x86/mm.c	Thu May 14 11:07:27 2009 +0100
@@ -766,7 +766,7 @@
         goto could_not_pin;
 
     if ( pte_flags_to_cacheattr(l1f) !=
-         ((page->count_info >> PGC_cacheattr_base) & 7) )
+         ((page->count_info & PGC_cacheattr_mask) >> PGC_cacheattr_base) )
     {
         unsigned long x, nx, y = page->count_info;
         unsigned long cacheattr = pte_flags_to_cacheattr(l1f);
@@ -782,7 +782,7 @@
             return 0;
         }
 
-        while ( ((y >> PGC_cacheattr_base) & 7) != cacheattr )
+        while ( ((y & PGC_cacheattr_mask) >> PGC_cacheattr_base) != cacheattr )
         {
             x  = y;
             nx = (x & ~PGC_cacheattr_mask) | (cacheattr << PGC_cacheattr_base);
@@ -2389,7 +2389,8 @@
 
 void cleanup_page_cacheattr(struct page_info *page)
 {
-    uint32_t cacheattr = (page->count_info >> PGC_cacheattr_base) & 7;
+    uint32_t cacheattr =
+        (page->count_info & PGC_cacheattr_mask) >> PGC_cacheattr_base;
 
     if ( likely(cacheattr == 0) )
         return;

Re: [PATCH] Fix get_page_from_l1e andcleanup_page_cacheattr to use PGC_cacheattr_mask

[Jan Beulich]

>>> Patrick Colp <Patrick.Colp@citrix.com> 15.05.09 11:01 >>>
># HG changeset patch
># User Patrick Colp <Patrick.Colp@citrix.com>
># Date 1242295647 -3600
># Node ID c5098f5c5caf4174bd2e46d49d7b65109203f7c5
># Parent  2522cc95efd2f3fadf7342d18fe86e8f37f89c2a
>Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask.

Could you indicate what it is that you fix here?

Jan

Re: [PATCH] Fix get_page_from_l1e andcleanup_page_cacheattr to use PGC_cacheattr_mask

[Patrick Colp]

Keir Fraser wrote:
> On 15/05/2009 10:31, "Jan Beulich" <JBeulich@novell.com> wrote:
> 
>>>>> Patrick Colp <Patrick.Colp@citrix.com> 15.05.09 11:01 >>>
>>> # HG changeset patch
>>> # User Patrick Colp <Patrick.Colp@citrix.com>
>>> # Date 1242295647 -3600
>>> # Node ID c5098f5c5caf4174bd2e46d49d7b65109203f7c5
>>> # Parent  2522cc95efd2f3fadf7342d18fe86e8f37f89c2a
>>> Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask.
>> Could you indicate what it is that you fix here?
> 
> I assume it's just getting rid of the open-coded 7.
> 
>  -- Keir

Yes, exactly.


Patrick

Re: [PATCH] Fix get_page_from_l1e andcleanup_page_cacheattr to use PGC_cacheattr_mask

[Keir Fraser]

On 15/05/2009 10:31, "Jan Beulich" <JBeulich@novell.com> wrote:

>>>> Patrick Colp <Patrick.Colp@citrix.com> 15.05.09 11:01 >>>
>> # HG changeset patch
>> # User Patrick Colp <Patrick.Colp@citrix.com>
>> # Date 1242295647 -3600
>> # Node ID c5098f5c5caf4174bd2e46d49d7b65109203f7c5
>> # Parent  2522cc95efd2f3fadf7342d18fe86e8f37f89c2a
>> Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask.
> 
> Could you indicate what it is that you fix here?

I assume it's just getting rid of the open-coded 7.

 -- Keir

Re: [PATCH] Fix get_page_from_l1eandcleanup_page_cacheattr to use PGC_cacheattr_mask

[Jan Beulich]

>>> Keir Fraser <keir.fraser@eu.citrix.com> 15.05.09 11:40 >>>
>On 15/05/2009 10:31, "Jan Beulich" <JBeulich@novell.com> wrote:
>
>>>>> Patrick Colp <Patrick.Colp@citrix.com> 15.05.09 11:01 >>>
>>> # HG changeset patch
>>> # User Patrick Colp <Patrick.Colp@citrix.com>
>>> # Date 1242295647 -3600
>>> # Node ID c5098f5c5caf4174bd2e46d49d7b65109203f7c5
>>> # Parent  2522cc95efd2f3fadf7342d18fe86e8f37f89c2a
>>> Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask.
>> 
>> Could you indicate what it is that you fix here?
>
>I assume it's just getting rid of the open-coded 7.

So would I have thought by looking at the patch, but the word 'fix' in the subject
made me thing there was something more subtle that I didn't spot...

Jan

Re: [PATCH] Fix get_page_from_l1eandcleanup_page_cacheattr to use PGC_cacheattr_mask

[Patrick Colp]

Jan Beulich wrote:
>>>> Keir Fraser <keir.fraser@eu.citrix.com> 15.05.09 11:40 >>>
>> On 15/05/2009 10:31, "Jan Beulich" <JBeulich@novell.com> wrote:
>>
>>>>>> Patrick Colp <Patrick.Colp@citrix.com> 15.05.09 11:01 >>>
>>>> # HG changeset patch
>>>> # User Patrick Colp <Patrick.Colp@citrix.com>
>>>> # Date 1242295647 -3600
>>>> # Node ID c5098f5c5caf4174bd2e46d49d7b65109203f7c5
>>>> # Parent  2522cc95efd2f3fadf7342d18fe86e8f37f89c2a
>>>> Fix get_page_from_l1e and cleanup_page_cacheattr to use PGC_cacheattr_mask.
>>> Could you indicate what it is that you fix here?
>> I assume it's just getting rid of the open-coded 7.
> 
> So would I have thought by looking at the patch, but the word 'fix' in the subject
> made me thing there was something more subtle that I didn't spot...
> 
> Jan

Nah, just a poor word choice. "Changed" would probably have been better.


Patrick