From: Dominik Dingel <dingel@linux.vnet.ibm.com>
Date: Fri, 17 Jul 2015 23:23:31 +0000 (-0700)
Subject: revert "s390/mm: change HPAGE_SHIFT type to int"
X-Git-Tag: v4.2-rc3~11^2~20
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=ad4f99e888192e53d463cab75075e88e65ad7d50;p=linux.git

revert "s390/mm: change HPAGE_SHIFT type to int"

Heiko noticed that the current check for hugepage support on s390 is a
little bit too harsh as systems which do not support will crash.

The reason is that pageblock_order can now get negative when we set
HPAGE_SHIFT to 0.  To avoid all this and to avoid opening another can of
worms with enabling HUGETLB_PAGE_SIZE_VARIABLE I think it would be best
to simply allow architectures to define their own hugepages_supported().

This patch (of 4): revert commit cf54e2fce51c ("s390/mm: change
HPAGE_SHIFT type to int") in preparation.

Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/arch/s390/include/asm/page.h b/arch/s390/include/asm/page.h
index dd345238d9a7..0844b780c6a4 100644
--- a/arch/s390/include/asm/page.h
+++ b/arch/s390/include/asm/page.h
@@ -20,7 +20,7 @@
 #include <asm/setup.h>
 #ifndef __ASSEMBLY__
 
-extern int HPAGE_SHIFT;
+extern unsigned int HPAGE_SHIFT;
 #define HPAGE_SIZE	(1UL << HPAGE_SHIFT)
 #define HPAGE_MASK	(~(HPAGE_SIZE - 1))
 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)
diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index 33082d0d101b..16154720bdb6 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -31,7 +31,7 @@
 #define ALLOC_ORDER	2
 #define FRAG_MASK	0x03
 
-int HPAGE_SHIFT;
+unsigned int HPAGE_SHIFT;
 
 unsigned long *crst_table_alloc(struct mm_struct *mm)
 {