[PATCH 1/5] loop: remove 'rw' parameter from lo_rw_aio()

[Ming Lei <ming.lei@xxxxxxxxxx>]

lo_rw_aio() is only called for READ/WRITE operation, which can be
figured out from request directly, so remove 'rw' parameter from
lo_rw_aio(), meantime rename the local variable as 'dir' which matches
the actual use more.

Meantime merge lo_read_simple() and lo_write_simple() into
lo_rw_simple().

Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
 drivers/block/loop.c | 48 ++++++++++++++++++--------------------------
 1 file changed, 19 insertions(+), 29 deletions(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 657bf53decf3..6bbbaa4aaf2c 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -239,31 +239,25 @@ static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos)
 	return bw;
 }
 
-static int lo_write_simple(struct loop_device *lo, struct request *rq,
-		loff_t pos)
-{
-	struct bio_vec bvec;
-	struct req_iterator iter;
-	int ret = 0;
-
-	rq_for_each_segment(bvec, rq, iter) {
-		ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
-		if (ret < 0)
-			break;
-		cond_resched();
-	}
-
-	return ret;
-}
-
-static int lo_read_simple(struct loop_device *lo, struct request *rq,
-		loff_t pos)
+static int lo_rw_simple(struct loop_device *lo, struct request *rq, loff_t pos)
 {
 	struct bio_vec bvec;
 	struct req_iterator iter;
 	struct iov_iter i;
 	ssize_t len;
 
+	if (req_op(rq) == REQ_OP_WRITE) {
+		int ret;
+
+		rq_for_each_segment(bvec, rq, iter) {
+			ret = lo_write_bvec(lo->lo_backing_file, &bvec, &pos);
+			if (ret < 0)
+				break;
+			cond_resched();
+		}
+		return ret;
+	}
+
 	rq_for_each_segment(bvec, rq, iter) {
 		iov_iter_bvec(&i, ITER_DEST, &bvec, 1, bvec.bv_len);
 		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
@@ -400,13 +394,13 @@ static void lo_rw_aio_complete(struct kiocb *iocb, long ret)
 	lo_rw_aio_do_completion(cmd);
 }
 
-static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
-		     loff_t pos, int rw)
+static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, loff_t pos)
 {
 	struct iov_iter iter;
 	struct req_iterator rq_iter;
 	struct bio_vec *bvec;
 	struct request *rq = blk_mq_rq_from_pdu(cmd);
+	int dir = (req_op(rq) == REQ_OP_READ) ? ITER_DEST : ITER_SOURCE;
 	struct bio *bio = rq->bio;
 	struct file *file = lo->lo_backing_file;
 	struct bio_vec tmp;
@@ -448,7 +442,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
 	}
 	atomic_set(&cmd->ref, 2);
 
-	iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq));
+	iov_iter_bvec(&iter, dir, bvec, nr_bvec, blk_rq_bytes(rq));
 	iter.iov_offset = offset;
 
 	cmd->iocb.ki_pos = pos;
@@ -457,7 +451,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
 	cmd->iocb.ki_flags = IOCB_DIRECT;
 	cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0);
 
-	if (rw == ITER_SOURCE)
+	if (dir == ITER_SOURCE)
 		ret = file->f_op->write_iter(&cmd->iocb, &iter);
 	else
 		ret = file->f_op->read_iter(&cmd->iocb, &iter);
@@ -498,15 +492,11 @@ static int do_req_filebacked(struct loop_device *lo, struct request *rq)
 	case REQ_OP_DISCARD:
 		return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
 	case REQ_OP_WRITE:
-		if (cmd->use_aio)
-			return lo_rw_aio(lo, cmd, pos, ITER_SOURCE);
-		else
-			return lo_write_simple(lo, rq, pos);
 	case REQ_OP_READ:
 		if (cmd->use_aio)
-			return lo_rw_aio(lo, cmd, pos, ITER_DEST);
+			return lo_rw_aio(lo, cmd, pos);
 		else
-			return lo_read_simple(lo, rq, pos);
+			return lo_rw_simple(lo, rq, pos);
 	default:
 		WARN_ON_ONCE(1);
 		return -EIO;
-- 
2.47.0