engines/null: allow build as external C++ ioengine

In first place to have a simple test candidate for external
ioengines using get_ioengine() method for retriving the
io_engine struct.

Can be compiled with:

g++ -O2 -g -shared -rdynamic -fPIC -o null.so null.c -DFIO_EXTERNAL_ENGINE

Signed-off-by: Daniel Gollub <d.gollub@telekom.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

diff --git a/engines/null.c b/engines/null.c
index bf7885e92187e68488c3c5109ca52ed77cd4fd36..9f9d8500b0516d393b756a10d1be5f9f19f00c59 100644 (file)
--- a/engines/null.c
+++ b/engines/null.c
@@ -4,6 +4,10 @@
  * IO engine that doesn't do any real IO transfers, it just pretends to.
  * The main purpose is to test fio itself.
  *
+ * It also can act as external C++ engine - compiled with:
+ *
+ * g++ -O2 -g -shared -rdynamic -fPIC -o null.so null.c -DFIO_EXTERNAL_ENGINE
+ *
  */
 #include <stdio.h>
 #include <stdlib.h>
@@ -21,7 +25,7 @@ struct null_data {
 
 static struct io_u *fio_null_event(struct thread_data *td, int event)
 {
-       struct null_data *nd = td->io_ops->data;
+       struct null_data *nd = (struct null_data *) td->io_ops->data;
 
        return nd->io_us[event];
 }
@@ -30,7 +34,7 @@ static int fio_null_getevents(struct thread_data *td, unsigned int min_events,
                              unsigned int fio_unused max,
                              struct timespec fio_unused *t)
 {
-       struct null_data *nd = td->io_ops->data;
+       struct null_data *nd = (struct null_data *) td->io_ops->data;
        int ret = 0;
        
        if (min_events) {
@@ -43,10 +47,12 @@ static int fio_null_getevents(struct thread_data *td, unsigned int min_events,
 
 static int fio_null_commit(struct thread_data *td)
 {
-       struct null_data *nd = td->io_ops->data;
+       struct null_data *nd = (struct null_data *) td->io_ops->data;
 
        if (!nd->events) {
+#ifndef FIO_EXTERNAL_ENGINE
                io_u_mark_submit(td, nd->queued);
+#endif
                nd->events = nd->queued;
                nd->queued = 0;
        }
@@ -56,7 +62,7 @@ static int fio_null_commit(struct thread_data *td)
 
 static int fio_null_queue(struct thread_data *td, struct io_u *io_u)
 {
-       struct null_data *nd = td->io_ops->data;
+       struct null_data *nd = (struct null_data *) td->io_ops->data;
 
        fio_ro_check(td, io_u);
 
@@ -77,7 +83,7 @@ static int fio_null_open(struct thread_data fio_unused *td,
 
 static void fio_null_cleanup(struct thread_data *td)
 {
-       struct null_data *nd = td->io_ops->data;
+       struct null_data *nd = (struct null_data *) td->io_ops->data;
 
        if (nd) {
                if (nd->io_us)
@@ -88,12 +94,12 @@ static void fio_null_cleanup(struct thread_data *td)
 
 static int fio_null_init(struct thread_data *td)
 {
-       struct null_data *nd = malloc(sizeof(*nd));
+       struct null_data *nd = (struct null_data *) malloc(sizeof(*nd));
 
        memset(nd, 0, sizeof(*nd));
 
        if (td->o.iodepth != 1) {
-               nd->io_us = malloc(td->o.iodepth * sizeof(struct io_u *));
+               nd->io_us = (struct io_u **) malloc(td->o.iodepth * sizeof(struct io_u *));
                memset(nd->io_us, 0, td->o.iodepth * sizeof(struct io_u *));
        } else
                td->io_ops->flags |= FIO_SYNCIO;
@@ -102,6 +108,7 @@ static int fio_null_init(struct thread_data *td)
        return 0;
 }
 
+#ifndef __cplusplus
 static struct ioengine_ops ioengine = {
        .name           = "null",
        .version        = FIO_IOOPS_VERSION,
@@ -124,3 +131,28 @@ static void fio_exit fio_null_unregister(void)
 {
        unregister_ioengine(&ioengine);
 }
+
+#else
+
+#ifdef FIO_EXTERNAL_ENGINE
+extern "C" {
+void get_ioengine(struct ioengine_ops **ioengine_ptr) {
+       struct ioengine_ops *ioengine;
+       *ioengine_ptr = (struct ioengine_ops *) malloc(sizeof(struct ioengine_ops));
+       ioengine = *ioengine_ptr;
+
+       strcpy(ioengine->name, "cpp_null");
+       ioengine->version        = FIO_IOOPS_VERSION;
+       ioengine->queue          = fio_null_queue;
+       ioengine->commit         = fio_null_commit;
+       ioengine->getevents      = fio_null_getevents;
+       ioengine->event          = fio_null_event;
+       ioengine->init           = fio_null_init;
+       ioengine->cleanup        = fio_null_cleanup;
+       ioengine->open_file      = fio_null_open;
+       ioengine->flags          = FIO_DISKLESSIO;
+}
+}
+#endif /* FIO_EXTERNAL_ENGINE */
+
+#endif /* __cplusplus */