virtio: Introduce vringh wrappers in virtio_config
Add wrappers for the host vrings to support loose
coupling between the virtio device and driver.
A new struct vringh_config_ops with the functions
find_vrhs() and del_vrhs() is added to the virtio_device
struct. This enables virtio drivers to manage virtio
host rings without detailed knowledge of how the
vrings are created and deleted.
The function vringh_notify() is added so vringh clients
can notify the other side that buffers are added to the
used-ring.
Cc: Ohad Ben-Cohen <ohad@wizery.com>
Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (constified vringh_config)
diff --git a/include/linux/vringh.h b/include/linux/vringh.h
index b8f0866..749cde2 100644
--- a/include/linux/vringh.h
+++ b/include/linux/vringh.h
@@ -47,6 +47,28 @@
/* The vring (note: it may contain user pointers!) */
struct vring vring;
+
+ /* The function to call to notify the guest about added buffers */
+ void (*notify)(struct vringh *);
+};
+
+/**
+ * struct vringh_config_ops - ops for creating a host vring from a virtio driver
+ * @find_vrhs: find the host vrings and instantiate them
+ * vdev: the virtio_device
+ * nhvrs: the number of host vrings to find
+ * hvrs: on success, includes new host vrings
+ * callbacks: array of driver callbacks, for each host vring
+ * include a NULL entry for vqs that do not need a callback
+ * Returns 0 on success or error status
+ * @del_vrhs: free the host vrings found by find_vrhs().
+ */
+struct virtio_device;
+typedef void vrh_callback_t(struct virtio_device *, struct vringh *);
+struct vringh_config_ops {
+ int (*find_vrhs)(struct virtio_device *vdev, unsigned nhvrs,
+ struct vringh *vrhs[], vrh_callback_t *callbacks[]);
+ void (*del_vrhs)(struct virtio_device *vdev);
};
/* The memory the vring can access, and what offset to apply. */
@@ -193,4 +215,11 @@
int vringh_need_notify_kern(struct vringh *vrh);
+/* Notify the guest about buffers added to the used ring */
+static inline void vringh_notify(struct vringh *vrh)
+{
+ if (vrh->notify)
+ vrh->notify(vrh);
+}
+
#endif /* _LINUX_VRINGH_H */