From: Chris Metcalf <cmetcalf@tilera.com>
Date: Mon, 24 May 2010 21:32:53 +0000 (-0700)
Subject: mm: make lowmem_page_address() use PFN_PHYS() for improved portability
X-Git-Tag: firefly_0821_release~9833^2~1966
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=c6f6b596a5a73e63e5e930c414375c0c389199ab;p=firefly-linux-kernel-4.4.55.git

mm: make lowmem_page_address() use PFN_PHYS() for improved portability

This ensures that platforms with lowmem PAs above 32 bits work correctly
by avoiding truncating the PA during a left shift.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: Barry Song <21cnbao@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 963f908af9d0..b969efb03787 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -13,6 +13,7 @@
 #include <linux/debug_locks.h>
 #include <linux/mm_types.h>
 #include <linux/range.h>
+#include <linux/pfn.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -595,7 +596,7 @@ static inline void set_page_links(struct page *page, enum zone_type zone,
 
 static __always_inline void *lowmem_page_address(struct page *page)
 {
-	return __va(page_to_pfn(page) << PAGE_SHIFT);
+	return __va(PFN_PHYS(page_to_pfn(page)));
 }
 
 #if defined(CONFIG_HIGHMEM) && !defined(WANT_PAGE_VIRTUAL)