Re: [PATCH v11 04/12] vdpa: Add reset callback in vdpa_config_ops

On Mon, Aug 23, 2021 at 2:31 PM Jason Wang [off-list ref] wrote:

在 2021/8/18 下午8:06, Xie Yongji 写道:

quoted

This adds a new callback to support device specific reset
behavior. The vdpa bus driver will call the reset function
instead of setting status to zero during resetting if device
driver supports the new callback.

Signed-off-by: Xie Yongji <redacted>
---
  drivers/vhost/vdpa.c |  9 +++++++--
  include/linux/vdpa.h | 11 ++++++++++-
  2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index b07aa161f7ad..b1c91b4db0ba 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c

@@ -157,7 +157,7 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
      struct vdpa_device *vdpa = v->vdpa;
      const struct vdpa_config_ops *ops = vdpa->config;
      u8 status, status_old;
-     int nvqs = v->nvqs;
+     int ret, nvqs = v->nvqs;
      u16 i;

      if (copy_from_user(&status, statusp, sizeof(status)))

@@ -172,7 +172,12 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
      if (status != 0 && (ops->get_status(vdpa) & ~status) != 0)
              return -EINVAL;

-     ops->set_status(vdpa, status);
+     if (status == 0 && ops->reset) {
+             ret = ops->reset(vdpa);
+             if (ret)
+                     return ret;
+     } else
+             ops->set_status(vdpa, status);

      if ((status & VIRTIO_CONFIG_S_DRIVER_OK) && !(status_old & VIRTIO_CONFIG_S_DRIVER_OK))
              for (i = 0; i < nvqs; i++)

diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 8a645f8f4476..af7ea5ad795f 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h

@@ -196,6 +196,9 @@ struct vdpa_iova_range {
   *                          @vdev: vdpa device
   *                          Returns the iova range supported by
   *                          the device.
+ * @reset:                   Reset device (optional)
+ *                           @vdev: vdpa device
+ *                           Returns integer: success (0) or error (< 0)

It looks to me we'd better make this mandatory. This help to reduce the
confusion for the parent driver.

OK, will do it in next version.

Thanks,
Yongji