On Fri, Jun 18, 2021 at 3:04 AM Stefano Garzarella [off-list ref] wrote:

On Wed, Jun 09, 2021 at 11:24:58PM +0000, Jiang Wang wrote:

quoted

Make rx buf len configurable via sysfs

Signed-off-by: Jiang Wang <redacted>
---
net/vmw_vsock/virtio_transport.c | 37 +++++++++++++++++++++++++++++++++++--
1 file changed, 35 insertions(+), 2 deletions(-)

diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
index cf47aadb0c34..2e4dd9c48472 100644
--- a/net/vmw_vsock/virtio_transport.c
+++ b/net/vmw_vsock/virtio_transport.c

@@ -29,6 +29,14 @@ static struct virtio_vsock __rcu *the_virtio_vsock;

static struct virtio_vsock *the_virtio_vsock_dgram;
static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */

+static int rx_buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+static struct kobject *kobj_ref;
+static ssize_t  sysfs_show(struct kobject *kobj,
+                      struct kobj_attribute *attr, char *buf);
+static ssize_t  sysfs_store(struct kobject *kobj,
+                      struct kobj_attribute *attr, const char *buf, size_t count);
+static struct kobj_attribute rxbuf_attr = __ATTR(rx_buf_value, 0660, sysfs_show, sysfs_store);

Maybe better to use a 'dgram' prefix.

Sure.

quoted

+
struct virtio_vsock {
      struct virtio_device *vdev;
      struct virtqueue **vqs;

@@ -360,7 +368,7 @@ virtio_transport_cancel_pkt(struct vsock_sock *vsk)

static void virtio_vsock_rx_fill(struct virtio_vsock *vsock, bool is_dgram)
{
-      int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE;
+      int buf_len = rx_buf_len;
      struct virtio_vsock_pkt *pkt;
      struct scatterlist hdr, buf, *sgs[2];
      struct virtqueue *vq;

@@ -1003,6 +1011,22 @@ static struct virtio_driver virtio_vsock_driver = {
      .remove = virtio_vsock_remove,

};

+static ssize_t sysfs_show(struct kobject *kobj,
+              struct kobj_attribute *attr, char *buf)
+{
+      return sprintf(buf, "%d", rx_buf_len);
+}
+
+static ssize_t sysfs_store(struct kobject *kobj,
+              struct kobj_attribute *attr, const char *buf, size_t count)
+{
+      if (kstrtou32(buf, 0, &rx_buf_len) < 0)
+              return -EINVAL;
+      if (rx_buf_len < 1024)
+              rx_buf_len = 1024;
+      return count;
+}
+
static int __init virtio_vsock_init(void)
{
      int ret;

@@ -1020,8 +1044,17 @@ static int __init virtio_vsock_init(void)
      if (ret)
              goto out_vci;

-      return 0;
+      kobj_ref = kobject_create_and_add("vsock", kernel_kobj);

So, IIUC, the path will be /sys/vsock/rx_buf_value?

I'm not sure if we need to add a `virtio` subdir (e.g.
/sys/vsock/virtio/dgram_rx_buf_size)

I agree adding a virtio is better in case vmware or hyperv will
also have some settings.

Thanks,
Stefano

quoted

+      /*Creating sysfs file for etx_value*/
+      ret = sysfs_create_file(kobj_ref, &rxbuf_attr.attr);
+      if (ret)
+              goto out_sysfs;
+
+      return 0;
+out_sysfs:
+      kobject_put(kobj_ref);
+      sysfs_remove_file(kernel_kobj, &rxbuf_attr.attr);
out_vci:
      vsock_core_unregister(&virtio_transport.transport);
out_wq:
--
2.11.0

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