md: more open-coded offset_in_page()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

drivers/md/bcache/util.c

@@ -230,7 +230,7 @@ void bch_bio_map(struct bio *bio, void *base)
 	BUG_ON(!bio->bi_iter.bi_size);
 	BUG_ON(bio->bi_vcnt);
 
-	bv->bv_offset = base ? ((unsigned long) base) % PAGE_SIZE : 0;
+	bv->bv_offset = base ? offset_in_page(base) : 0;
 	goto start;
 
 	for (; size; bio->bi_vcnt++, bv++) {

drivers/md/dm-io.c

@@ -246,7 +246,7 @@ static void vm_dp_init(struct dpages *dp, void *data)
 {
 	dp->get_page = vm_get_page;
 	dp->next_page = vm_next_page;
-	dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
+	dp->context_u = offset_in_page(data);
 	dp->context_ptr = data;
 }
 
@@ -271,7 +271,7 @@ static void km_dp_init(struct dpages *dp, void *data)
 {
 	dp->get_page = km_get_page;
 	dp->next_page = km_next_page;
-	dp->context_u = ((unsigned long) data) & (PAGE_SIZE - 1);
+	dp->context_u = offset_in_page(data);
 	dp->context_ptr = data;
 }