[PATCH 3.2 23/46] s390/hugetlb: add hugepages_supported define

[Ben Hutchings]

3.2.81-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>

commit 7f9be77555bb2e52de84e9dddf7b4eb20cc6e171 upstream.

On s390 we only can enable hugepages if the underlying hardware/hypervisor
also does support this.  Common code now would assume this to be
signaled by setting HPAGE_SHIFT to 0.  But on s390, where we only
support one hugepage size, there is a link between HPAGE_SHIFT and
pageblock_order.

So instead of setting HPAGE_SHIFT to 0, we will implement the check for
the hardware capability.

Signed-off-by: Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx>
Acked-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Michael Holzheu <holzheu@xxxxxxxxxxxxxxxxxx>
Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 arch/s390/include/asm/hugetlb.h | 1 +
 1 file changed, 1 insertion(+)

--- a/arch/s390/include/asm/hugetlb.h
+++ b/arch/s390/include/asm/hugetlb.h
@@ -14,6 +14,7 @@
 
 #define is_hugepage_only_range(mm, addr, len)	0
 #define hugetlb_free_pgd_range			free_pgd_range
+#define hugepages_supported()			(MACHINE_HAS_HPAGE)
 
 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 		     pte_t *ptep, pte_t pte);