vdpa: Avoid taking cf_mutex lock on get status

Avoid the wrapper holding cf_mutex since it is not protecting anything.
To avoid confusion and unnecessary overhead incurred by it, remove.

Fixes: f489f27 ("vdpa: Sync calls set/get config/status with cf_mutex")
Signed-off-by: Eli Cohen <elic@nvidia.com>
Link: https://lore.kernel.org/r/20220111183400.38418-2-elic@nvidia.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Si-Wei Liu<si-wei.liu@oracle.com>
Acked-by: Jason Wang <jasowang@redhat.com>

drivers/vdpa/vdpa.c

@@ -21,17 +21,6 @@ static LIST_HEAD(mdev_head);
 static DEFINE_MUTEX(vdpa_dev_mutex);
 static DEFINE_IDA(vdpa_index_ida);
 
-u8 vdpa_get_status(struct vdpa_device *vdev)
-{
-	u8 status;
-
-	mutex_lock(&vdev->cf_mutex);
-	status = vdev->config->get_status(vdev);
-	mutex_unlock(&vdev->cf_mutex);
-	return status;
-}
-EXPORT_SYMBOL(vdpa_get_status);
-
 void vdpa_set_status(struct vdpa_device *vdev, u8 status)
 {
 	mutex_lock(&vdev->cf_mutex);

drivers/vhost/vdpa.c

@@ -142,9 +142,10 @@ static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp)
 static long vhost_vdpa_get_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 = vdpa_get_status(vdpa);
+	status = ops->get_status(vdpa);
 
 	if (copy_to_user(statusp, &status, sizeof(status)))
 		return -EFAULT;
@@ -163,7 +164,7 @@ static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
 	if (copy_from_user(&status, statusp, sizeof(status)))
 		return -EFAULT;
 
-	status_old = vdpa_get_status(vdpa);
+	status_old = ops->get_status(vdpa);
 
 	/*
 	 * Userspace shouldn't remove status bits unless reset the

include/linux/vdpa.h

@@ -421,7 +421,6 @@ void vdpa_get_config(struct vdpa_device *vdev, unsigned int offset,
 		     void *buf, unsigned int len);
 void vdpa_set_config(struct vdpa_device *dev, unsigned int offset,
 		     const void *buf, unsigned int length);
-u8 vdpa_get_status(struct vdpa_device *vdev);
 void vdpa_set_status(struct vdpa_device *vdev, u8 status);
 
 /**