From: Jens Axboe <jens.axboe@oracle.com>
Date: Tue, 7 Nov 2006 15:02:11 +0000 (+0100)
Subject: [PATCH] Add skeleton external io engine
X-Git-Tag: fio-1.10~31
X-Git-Url: https://git.kernel.dk/?p=fio.git;a=commitdiff_plain;h=da51c0505c753f64ad5f65808377b8f67b445828;hp=5f350952eff89948bfbf1eb6ac4d3d08a9109581

[PATCH] Add skeleton external io engine

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
---

diff --git a/engines/fio-engine-skeleton_external.c b/engines/fio-engine-skeleton_external.c
new file mode 100644
index 00000000..497baa6c
--- /dev/null
+++ b/engines/fio-engine-skeleton_external.c
@@ -0,0 +1,37 @@
+/*
+ * Skeleton for a sample external io engine
+ *
+ * Should be compiled with:
+ *
+ * gcc -Wall -O2 -g -shared -rdynamic -fPIC -o engine.o engine.c
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <assert.h>
+
+#include "../fio.h"
+#include "../os.h"
+
+/*
+ * The core of the module is identical to the ones included with fio,
+ * read those. You cannot use register_ioengine() and unregister_ioengine()
+ * for external modules, they should be gotten through dlsym()
+ */
+
+/*
+ * Note that the structure is exported, so that fio can get it via
+ * dlsym(..., "ioengine");
+ */
+struct ioengine_ops ioengine = {
+	.name		= "engine_name",
+	.version	= FIO_IOOPS_VERSION,
+	.init		= fio_skeleton_init,
+	.prep		= fio_skeleton_prep,
+	.queue		= fio_skeleton_queue,
+	.getevents	= fio_skeleton_getevents,
+	.event		= fio_skeleton_event,
+	.cleanup	= fio_skeleton_cleanup,
+};
diff --git a/ioengines.c b/ioengines.c
index a71357c6..56a718c6 100644
--- a/ioengines.c
+++ b/ioengines.c
@@ -98,6 +98,10 @@ static struct ioengine_ops *dlopen_ioengine(struct thread_data *td,
 		return NULL;
 	}
 
+	/*
+	 * Unlike the included modules, external engines should have a
+	 * non-static ioengine structure that we can reference.
+	 */
 	ops = dlsym(dlhandle, "ioengine");
 	if (!ops) {
 		td_vmsg(td, -1, dlerror());