[PATCH] loop: debug: add threaded aio

[Ming Lei <ming.lei@xxxxxxxxxx>]

Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
---
 drivers/block/loop.c | 47 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 46 insertions(+), 1 deletion(-)

diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 393f38573169..113e29b3ac80 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -86,6 +86,8 @@ struct loop_cmd {
 	struct bio_vec *bvec;
 	struct cgroup_subsys_state *blkcg_css;
 	struct cgroup_subsys_state *memcg_css;
+
+	struct work_struct work;
 };
 
 #define LOOP_IDLE_WORKER_TIMEOUT (60 * HZ)
@@ -98,6 +100,8 @@ static DEFINE_IDR(loop_index_idr);
 static DEFINE_MUTEX(loop_ctl_mutex);
 static DEFINE_MUTEX(loop_validate_mutex);
 
+static unsigned int threaded_aio = 0;
+
 /**
  * loop_global_lock_killable() - take locks for safe loop_validate_file() test
  *
@@ -508,10 +512,17 @@ static int lo_rw_aio_prep(struct loop_device *lo, struct loop_cmd *cmd,
 static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, loff_t pos)
 {
 	unsigned int nr_bvec = lo_cmd_nr_bvec(cmd);
-	int ret;
+	int ret = 0;
+
+	if (threaded_aio) {
+		ret = lo_rw_aio_prep(lo, cmd, nr_bvec);
+		if (ret < 0)
+			goto exit;
+	}
 
 	cmd->iocb.ki_flags &= ~IOCB_NOWAIT;
 	ret = lo_submit_rw_aio(lo, cmd, pos, nr_bvec);
+exit:
 	if (ret != -EIOCBQUEUED)
 		lo_rw_aio_complete(&cmd->iocb, ret);
 	return 0;
@@ -1941,10 +1952,39 @@ static const struct kernel_param_ops loop_nr_hw_q_param_ops = {
 device_param_cb(nr_hw_queues, &loop_nr_hw_q_param_ops, &nr_hw_queues, 0444);
 MODULE_PARM_DESC(nr_hw_queues, "number of hardware queues. Default: " __stringify(LOOP_DEFAULT_NR_HW_Q));
 
+module_param(threaded_aio, uint, 0644);
+MODULE_PARM_DESC(threaded_aio, "threaded aio");
+
 MODULE_DESCRIPTION("Loopback device support");
 MODULE_LICENSE("GPL");
 MODULE_ALIAS_BLOCKDEV_MAJOR(LOOP_MAJOR);
 
+static void loop_aio_workfn(struct work_struct *work)
+{
+	struct loop_cmd *cmd = container_of(work, struct loop_cmd, work);
+	struct request *rq = blk_mq_rq_from_pdu(cmd);
+	struct loop_device *lo = rq->q->queuedata;
+	int ret = do_req_filebacked(lo, rq);
+
+	if (!cmd->use_aio || ret) {
+		if (ret == -EOPNOTSUPP)
+			cmd->ret = ret;
+		else
+			cmd->ret = ret ? -EIO : 0;
+		if (likely(!blk_should_fake_timeout(rq->q)))
+			blk_mq_complete_request(rq);
+	}
+}
+
+static void loop_queue_rq_threaded_aio(struct loop_cmd *cmd)
+{
+	struct request *rq = blk_mq_rq_from_pdu(cmd);
+	struct loop_device *lo = rq->q->queuedata;
+
+	INIT_WORK(&cmd->work, loop_aio_workfn);
+	queue_work(lo->workqueue, &cmd->work);
+}
+
 static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		const struct blk_mq_queue_data *bd)
 {
@@ -1968,6 +2008,11 @@ static blk_status_t loop_queue_rq(struct blk_mq_hw_ctx *hctx,
 		break;
 	}
 
+	if (threaded_aio) {
+		loop_queue_rq_threaded_aio(cmd);
+		return BLK_STS_OK;
+	}
+
 	if (cmd->use_aio) {
 		loff_t pos = ((loff_t) blk_rq_pos(rq) << 9) + lo->lo_offset;
 		int ret = lo_rw_aio_nowait(lo, cmd, pos);
-- 
2.47.1


--Vm1n1dgSJ9DBvycV--