thp: change insert_pfn's return type to void

It would make more sense to have all the return values from
vmf_insert_pfn_pmd() encoded in one place instead of having to follow
the convention into insert_pfn().  Suggested by Jeff Moyer.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/huge_memory.c

@@ -869,7 +869,7 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
 					    flags);
 }
 
-static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
+static void insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 		pmd_t *pmd, unsigned long pfn, pgprot_t prot, bool write)
 {
 	struct mm_struct *mm = vma->vm_mm;
@@ -887,7 +887,6 @@ static int insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 		update_mmu_cache_pmd(vma, addr, pmd);
 	}
 	spin_unlock(ptl);
-	return VM_FAULT_NOPAGE;
 }
 
 int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
@@ -909,7 +908,8 @@ int vmf_insert_pfn_pmd(struct vm_area_struct *vma, unsigned long addr,
 		return VM_FAULT_SIGBUS;
 	if (track_pfn_insert(vma, &pgprot, pfn))
 		return VM_FAULT_SIGBUS;
-	return insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write);
+	insert_pfn_pmd(vma, addr, pmd, pfn, pgprot, write);
+	return VM_FAULT_NOPAGE;
 }
 
 int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,