[patch] hugetlb: remove dummy definitions of HPAGE_MASK andHPAGE_SIZE

From: David Rientjes
Date: Thu Nov 17 2011 - 18:22:59 EST


Dummy, non-zero definitions for HPAGE_MASK and HPAGE_SIZE were added in
51c6f666fceb ("mm: ZAP_BLOCK causes redundant work") to avoid a divide
by zero in generic kernel code.

That code has since been removed, but probably should never have been
added in the first place: we don't want HPAGE_SIZE to act like PAGE_SIZE
for code that is working with hugepages, for example, when the dependency
on CONFIG_HUGETLB_PAGE has not been fulfilled.

Because hugepage size can differ from architecture to architecture, each
is required to have their own definitions for both HPAGE_MASK and
HPAGE_SIZE. This is always done in arch/*/include/asm/page.h.

So, just remove the dummy and dangerous definitions since they are no
longer needed and reveals the correct dependencies. Tested on
architectures using the definitions with allyesconfig: x86 (even with
thp), hppa, mips, powerpc, s390, sh3, sh4, sparc, and sparc64, and
with defconfig on ia64.

Cc: Robin Holt <holt@xxxxxxx>
Cc: David Daney <david.daney@xxxxxxxxxx>
Signed-off-by: David Rientjes <rientjes@xxxxxxxxxx>
---
include/linux/hugetlb.h | 5 -----
1 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -110,11 +110,6 @@ static inline void copy_huge_page(struct page *dst, struct page *src)

#define hugetlb_change_protection(vma, address, end, newprot)

-#ifndef HPAGE_MASK
-#define HPAGE_MASK PAGE_MASK /* Keep the compiler happy */
-#define HPAGE_SIZE PAGE_SIZE
-#endif
-
#endif /* !CONFIG_HUGETLB_PAGE */

#define HUGETLB_ANON_FILE "anon_hugepage"
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