[PATCH RFC v3 2/4] vhost/test: add an option to test new code

From: Michael S. Tsirkin
Date: Sun Oct 13 2019 - 04:08:43 EST


Add a writeable module parameter that tests
the new code. Note: no effort was made to ensure
things work correctly if the parameter is changed
while the device is open. Make sure to
close the device before changing its value.

Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
drivers/vhost/test.c | 17 +++++++++++++----
1 file changed, 13 insertions(+), 4 deletions(-)

diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index 056308008288..39a018a7af2d 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c
@@ -18,6 +18,9 @@
#include "test.h"
#include "vhost.h"

+static int newcode = 0;
+module_param(newcode, int, 0644);
+
/* Max number of bytes transferred before requeueing the job.
* Using this limit prevents one virtqueue from starving others. */
#define VHOST_TEST_WEIGHT 0x80000
@@ -58,10 +61,16 @@ static void handle_vq(struct vhost_test *n)
vhost_disable_notify(&n->dev, vq);

for (;;) {
- head = vhost_get_vq_desc(vq, vq->iov,
- ARRAY_SIZE(vq->iov),
- &out, &in,
- NULL, NULL);
+ if (newcode)
+ head = vhost_get_vq_desc_batch(vq, vq->iov,
+ ARRAY_SIZE(vq->iov),
+ &out, &in,
+ NULL, NULL);
+ else
+ head = vhost_get_vq_desc(vq, vq->iov,
+ ARRAY_SIZE(vq->iov),
+ &out, &in,
+ NULL, NULL);
/* On error, stop handling until the next kick. */
if (unlikely(head < 0))
break;
--
MST