dm: pass dm_io instance to dm_io_acct directly

All the other 4 parameters are retrieved from the 'dm_io' instance, so
it's not necessary to pass all four to dm_io_acct().
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

drivers/md/dm.c

@@ -502,9 +502,12 @@ static bool bio_is_flush_with_data(struct bio *bio)
 	return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size);
 }
 
-static void dm_io_acct(bool end, struct mapped_device *md, struct bio *bio,
-		       unsigned long start_time, struct dm_stats_aux *stats_aux)
+static void dm_io_acct(struct dm_io *io, bool end)
 {
+	struct dm_stats_aux *stats_aux = &io->stats_aux;
+	unsigned long start_time = io->start_time;
+	struct mapped_device *md = io->md;
+	struct bio *bio = io->orig_bio;
 	bool is_flush_with_data;
 	unsigned int bi_size;
 
@@ -533,7 +536,7 @@ static void dm_io_acct(bool end, struct mapped_device *md, struct bio *bio,
 
 static void __dm_start_io_acct(struct dm_io *io)
 {
-	dm_io_acct(false, io->md, io->orig_bio, io->start_time, &io->stats_aux);
+	dm_io_acct(io, false);
 }
 
 static void dm_start_io_acct(struct dm_io *io, struct bio *clone)
@@ -560,7 +563,7 @@ static void dm_start_io_acct(struct dm_io *io, struct bio *clone)
 
 static void dm_end_io_acct(struct dm_io *io)
 {
-	dm_io_acct(true, io->md, io->orig_bio, io->start_time, &io->stats_aux);
+	dm_io_acct(io, true);
 }
 
 static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio)