mm: fix __page_to_pfn for a const struct page argument
This allows the cast in lowmem_page_address (introduced as a warning
fixup to 33dd4e0ec911 "mm: make some struct page's const") to be
removed.
Propagate const'ness to page_to_section() as well since it is required
by __page_to_pfn.
Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/asm-generic/memory_model.h b/include/asm-generic/memory_model.h
index fb2d63f..aea9e45 100644
--- a/include/asm-generic/memory_model.h
+++ b/include/asm-generic/memory_model.h
@@ -39,7 +39,7 @@
})
#define __page_to_pfn(pg) \
-({ struct page *__pg = (pg); \
+({ const struct page *__pg = (pg); \
struct pglist_data *__pgdat = NODE_DATA(page_to_nid(__pg)); \
(unsigned long)(__pg - __pgdat->node_mem_map) + \
__pgdat->node_start_pfn; \
@@ -57,7 +57,7 @@
* section[i].section_mem_map == mem_map's address - start_pfn;
*/
#define __page_to_pfn(pg) \
-({ struct page *__pg = (pg); \
+({ const struct page *__pg = (pg); \
int __sec = page_to_section(__pg); \
(unsigned long)(__pg - __section_mem_map_addr(__nr_to_section(__sec))); \
})
diff --git a/include/linux/mm.h b/include/linux/mm.h
index c06454d..7438071 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -685,7 +685,7 @@
page->flags |= (section & SECTIONS_MASK) << SECTIONS_PGSHIFT;
}
-static inline unsigned long page_to_section(struct page *page)
+static inline unsigned long page_to_section(const struct page *page)
{
return (page->flags >> SECTIONS_PGSHIFT) & SECTIONS_MASK;
}
@@ -720,7 +720,7 @@
static __always_inline void *lowmem_page_address(const struct page *page)
{
- return __va(PFN_PHYS(page_to_pfn((struct page *)page)));
+ return __va(PFN_PHYS(page_to_pfn(page)));
}
#if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)