mm: Use static initialisers for immutable fields of 'struct vm_fault'

In preparation for const-ifying the anonymous struct field of
'struct vm_fault', ensure that it is initialised using designated
initialisers.

Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Will Deacon <will@kernel.org>

mm/shmem.c

@@ -1520,11 +1520,11 @@ static struct page *shmem_swapin(swp_entry_t swap, gfp_t gfp,
 {
 	struct vm_area_struct pvma;
 	struct page *page;
-	struct vm_fault vmf;
+	struct vm_fault vmf = {
+		.vma = &pvma,
+	};
 
 	shmem_pseudo_vma_init(&pvma, info, index);
-	vmf.vma = &pvma;
-	vmf.address = 0;
 	page = swap_cluster_readahead(swap, gfp, &vmf);
 	shmem_pseudo_vma_destroy(&pvma);
 

mm/swapfile.c

@@ -1951,8 +1951,6 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 	si = swap_info[type];
 	pte = pte_offset_map(pmd, addr);
 	do {
-		struct vm_fault vmf;
-
 		if (!is_swap_pte(*pte))
 			continue;
 
@@ -1968,9 +1966,12 @@ static int unuse_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 		swap_map = &si->swap_map[offset];
 		page = lookup_swap_cache(entry, vma, addr);
 		if (!page) {
-			vmf.vma = vma;
-			vmf.address = addr;
-			vmf.pmd = pmd;
+			struct vm_fault vmf = {
+				.vma = vma,
+				.address = addr,
+				.pmd = pmd,
+			};
+
 			page = swapin_readahead(entry, GFP_HIGHUSER_MOVABLE,
 						&vmf);
 		}