[PATCH 2/4] mm: Enable set_page_section() only if CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP

[PATCH 2/4] mm: Enable set_page_section() only if CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP

[Daniel Kiper]

set_page_section() is valid only in CONFIG_SPARSEMEM and
!CONFIG_SPARSEMEM_VMEMMAP context. Move it to proper place
and amend accordingly functions which are using it.

Signed-off-by: Daniel Kiper <dkiper@net-space.pl>
---
 include/linux/mm.h |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 692dbae..23465e1 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -680,6 +680,12 @@ static inline struct zone *page_zone(struct page *page)
 }
 
 #if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
+static inline void set_page_section(struct page *page, unsigned long section)
+{
+	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
+	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
+}
+
 static inline unsigned long page_to_section(struct page *page)
 {
 	return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
@@ -698,18 +704,14 @@ static inline void set_page_node(struct page *page, unsigned long node)
 	page->flags |= (node & NODES_MASK) << NODES_PGSHIFT;
 }
 
-static inline void set_page_section(struct page *page, unsigned long section)
-{
-	page->flags &= ~(SECTIONS_MASK << SECTIONS_PGSHIFT);
-	page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
-}
-
 static inline void set_page_links(struct page *page, enum zone_type zone,
 	unsigned long node, unsigned long pfn)
 {
 	set_page_zone(page, zone);
 	set_page_node(page, node);
+#if defined(CONFIG_SPARSEMEM) && !defined(CONFIG_SPARSEMEM_VMEMMAP)
 	set_page_section(page, pfn_to_section_nr(pfn));
+#endif
 }
 
 /*
-- 
1.5.6.5

Re: [PATCH 2/4] mm: Enable set_page_section() only if CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP

[Dave Hansen]

On Mon, 2011-05-02 at 23:20 +0200, Daniel Kiper wrote:
> set_page_section() is valid only in CONFIG_SPARSEMEM and
> !CONFIG_SPARSEMEM_VMEMMAP context. Move it to proper place
> and amend accordingly functions which are using it.

I guess we've been wasting all that time setting section bits in
page->flags that we'll never use.  Looks sane to me.

Acked-by: Dave Hansen <dave@linux.vnet.ibm.com>

-- Dave

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Re: [PATCH 2/4] mm: Enable set_page_section() only if CONFIG_SPARSEMEM and !CONFIG_SPARSEMEM_VMEMMAP

[David Rientjes]

On Mon, 2 May 2011, Daniel Kiper wrote:

> set_page_section() is valid only in CONFIG_SPARSEMEM and
> !CONFIG_SPARSEMEM_VMEMMAP context.

s/valid/needed/.  set_page_section() _is_ valid in all contexts since 
SECTIONS_MASK and SECTIONS_PGSHIFT is defined in all contexts.  

> Move it to proper place
> and amend accordingly functions which are using it.
> 
> Signed-off-by: Daniel Kiper <dkiper@net-space.pl>

After the changelog is fixed:

	Acked-by: David Rientjes <rientjes@google.com>

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