From 65afa5f2146ee010b7129934f68e691faee54982 Mon Sep 17 00:00:00 2001
From: Jens Axboe <jens.axboe@oracle.com>
Date: Fri, 9 Mar 2007 13:23:14 +0100
Subject: [PATCH] null engine: update to support queuing

Useful for queue testing.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---
 engines/null.c | 78 +++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 74 insertions(+), 4 deletions(-)

diff --git a/engines/null.c b/engines/null.c
index cd446b99..19886789 100644
--- a/engines/null.c
+++ b/engines/null.c
@@ -11,11 +11,48 @@
 #include "../fio.h"
 #include "../os.h"
 
+struct null_data {
+	struct io_u **io_us;
+	int queued;
+	int events;
+};
+
+static struct io_u *fio_null_event(struct thread_data *td, int event)
+{
+	struct null_data *nd = td->io_ops->data;
+
+	return nd->io_us[event];
+}
+
+static int fio_null_getevents(struct thread_data *td, int fio_unused min,
+			      int fio_unused max, struct timespec fio_unused *t)
+{
+	struct null_data *nd = td->io_ops->data;
+	int ret;
+
+	ret = nd->events;
+	nd->events = 0;
+	return ret;
+}
+
+static int fio_null_commit(struct thread_data *td)
+{
+	struct null_data *nd = td->io_ops->data;
+
+	nd->events = nd->queued;
+	nd->queued = 0;
+	return 0;
+}
+
 static int fio_null_queue(struct thread_data fio_unused *td, struct io_u *io_u)
 {
-	io_u->resid = 0;
-	io_u->error = 0;
-	return FIO_Q_COMPLETED;
+	struct null_data *nd = td->io_ops->data;
+
+	if (td->io_ops->flags & FIO_SYNCIO)
+		return FIO_Q_COMPLETED;
+
+	nd->io_us[nd->queued++] = io_u;
+	return FIO_Q_QUEUED;
 }
 
 static int fio_null_setup(struct thread_data *td)
@@ -46,13 +83,46 @@ static int fio_null_open(struct thread_data fio_unused *td,
 	return 0;
 }
 
+static void fio_null_cleanup(struct thread_data *td)
+{
+	struct null_data *nd = td->io_ops->data;
+
+	if (nd) {
+		if (nd->io_us)
+			free(nd->io_us);
+		free(nd);
+		td->io_ops->data = NULL;
+	}
+}
+
+static int fio_null_init(struct thread_data *td)
+{
+	struct null_data *nd = malloc(sizeof(*nd));
+
+	memset(nd, 0, sizeof(*nd));
+
+	if (td->iodepth != 1) {
+		nd->io_us = malloc(td->iodepth * sizeof(struct io_u *));
+		memset(nd->io_us, 0, td->iodepth * sizeof(struct io_u *));
+	} else
+		td->io_ops->flags |= FIO_SYNCIO;
+
+	td->io_ops->data = nd;
+	return 0;
+}
+
 static struct ioengine_ops ioengine = {
 	.name		= "null",
 	.version	= FIO_IOOPS_VERSION,
 	.setup		= fio_null_setup,
 	.queue		= fio_null_queue,
+	.commit		= fio_null_commit,
+	.getevents	= fio_null_getevents,
+	.event		= fio_null_event,
+	.init		= fio_null_init,
+	.cleanup	= fio_null_cleanup,
 	.open_file	= fio_null_open,
-	.flags		= FIO_SYNCIO | FIO_DISKLESSIO,
+	.flags		= FIO_DISKLESSIO,
 };
 
 static void fio_init fio_null_register(void)
-- 
2.25.1