mm/hugetlb: reduce arch dependent code about huge_pmd_unshare

Currently we have many duplicates in definitions of huge_pmd_unshare.  In
all architectures this function just returns 0 when
CONFIG_ARCH_WANT_HUGE_PMD_SHARE is N.

This patch puts the default implementation in mm/hugetlb.c and lets these
architectures use the common code.

Signed-off-by: Zhang Zhen <zhenzhang.zhang@huawei.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: David Rientjes <rientjes@google.com>
Cc: James Yang <James.Yang@freescale.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 271e4432734c..716465ae57aa 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3789,6 +3789,11 @@ pte_t *huge_pmd_share(struct mm_struct *mm, unsigned long addr, pud_t *pud)
 {
         return NULL;
 }
+
+int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
+{
+        return 0;
+}
 #define want_pmd_share()        (0)
 #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */