mm: hugetlb: allow hugepages_supported to be architecture specific

s390 has a constant hugepage size, by setting HPAGE_SHIFT we also change
e.g. the pageblock_order, which should be independent in respect to
hugepage support.

With this patch every architecture is free to define how to check
for hugepage support.

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/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 2050261..d891f94 100644 (file)
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -460,15 +460,14 @@ static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
        return &mm->page_table_lock;
 }
 
-static inline bool hugepages_supported(void)
-{
-       /*
-        * Some platform decide whether they support huge pages at boot
-        * time. On these, such as powerpc, HPAGE_SHIFT is set to 0 when
-        * there is no such support
-        */
-       return HPAGE_SHIFT != 0;
-}
+#ifndef hugepages_supported
+/*
+ * Some platform decide whether they support huge pages at boot
+ * time. Some of them, such as powerpc, set HPAGE_SHIFT to 0
+ * when there is no such support
+ */
+#define hugepages_supported() (HPAGE_SHIFT != 0)
+#endif
 
 #else  /* CONFIG_HUGETLB_PAGE */
 struct hstate {};