[PATCH] mm: hugetlb: replace some macros with inline functions

[Arnd Bergmann <arnd@arndb.de>]

All users of dissolve_free_huge_page() that ignore the result cause a warning
when CONFIG_HUGETLB_PAGE is disabled:

mm/memory-failure.c: In function 'me_huge_page':
include/linux/hugetlb.h:556:36: error: statement with no effect [-Werror=unused-value]
 #define dissolve_free_huge_page(p) 0

We can avoid this by using an inline function instead of the macro, and I
decided to do the same change for the related helpers as well.

Fixes: mmotm ("mm: hugetlb: soft-offline: dissolve source hugepage after successful migration")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/hugetlb.h | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index dbb118c566cd..57f700ac127e 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -546,16 +546,37 @@ static inline unsigned int pages_per_huge_page(struct hstate *h)
 {
 	return 1;
 }
-#define hstate_index_to_shift(index) 0
-#define hstate_index(h) 0
+
+static inline unsigned hstate_index_to_shift(unsigned index)
+{
+	return 0;
+}
+
+static inline int hstate_index(struct hstate *h)
+{
+	return 0;
+}
 
 static inline pgoff_t basepage_index(struct page *page)
 {
 	return page->index;
 }
-#define dissolve_free_huge_page(p)	0
-#define dissolve_free_huge_pages(s, e)	0
-#define hugepage_migration_supported(h)	false
+
+static inline int dissolve_free_huge_page(struct page *page)
+{
+	return 0;
+}
+
+static inline int dissolve_free_huge_pages(unsigned long start_pfn,
+					   unsigned long end_pfn)
+{
+	return 0;
+}
+
+static inline bool hugepage_migration_supported(struct hstate *h)
+{
+	return false;
+}
 
 static inline spinlock_t *huge_pte_lockptr(struct hstate *h,
 					   struct mm_struct *mm, pte_t *pte)
-- 
2.9.0