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 dd345238d9a7762becd9276602122d00b9e87ea5..0844b780c6a44b893a9d9e843e2e4b08062c5eeb 100644 (file)
--- 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 33082d0d101b59e41690435b7f35896cde14fe0f..16154720bdb60749163ec8ae33b4c451aa044c21 100644 (file)
--- 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)
 {