[PATCH RFC v4 4/5] vhost/net: add an option to test new code

From: Michael S. Tsirkin
Date: Sun Oct 13 2019 - 07:42:26 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/net.c | 32 +++++++++++++++++++++++++-------
1 file changed, 25 insertions(+), 7 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 1a2dd53caade..122b666ec1f2 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -35,6 +35,9 @@

#include "vhost.h"

+static int newcode = 0;
+module_param(newcode, int, 0644);
+
static int experimental_zcopytx = 0;
module_param(experimental_zcopytx, int, 0444);
MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
@@ -565,8 +568,14 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
struct vhost_virtqueue *rvq = &rnvq->vq;
struct vhost_virtqueue *tvq = &tnvq->vq;

- int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
- out_num, in_num, NULL, NULL);
+ int r;
+
+ if (newcode)
+ r = vhost_get_vq_desc_batch(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+ out_num, in_num, NULL, NULL);
+ else
+ r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+ out_num, in_num, NULL, NULL);

if (r == tvq->num && tvq->busyloop_timeout) {
/* Flush batched packets first */
@@ -575,8 +584,12 @@ static int vhost_net_tx_get_vq_desc(struct vhost_net *net,

vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false);

- r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
- out_num, in_num, NULL, NULL);
+ if (newcode)
+ r = vhost_get_vq_desc_batch(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+ out_num, in_num, NULL, NULL);
+ else
+ r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
+ out_num, in_num, NULL, NULL);
}

return r;
@@ -1046,9 +1059,14 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
r = -ENOBUFS;
goto err;
}
- r = vhost_get_vq_desc(vq, vq->iov + seg,
- ARRAY_SIZE(vq->iov) - seg, &out,
- &in, log, log_num);
+ if (newcode)
+ r = vhost_get_vq_desc_batch(vq, vq->iov + seg,
+ ARRAY_SIZE(vq->iov) - seg, &out,
+ &in, log, log_num);
+ else
+ r = vhost_get_vq_desc(vq, vq->iov + seg,
+ ARRAY_SIZE(vq->iov) - seg, &out,
+ &in, log, log_num);
if (unlikely(r < 0))
goto err;

--
MST