Re: [PATCH v6 07/18] drm/virtio: add virtio_gpu_object_array & helpers

Some helper functions to manage an array of gem objects.

v6:
 - add ticket to struct virtio_gpu_object_array.
 - add virtio_gpu_array_{lock,unlock}_resv helpers.
 - add virtio_gpu_array_add_fence helper.
v5: some small optimizations (Chia-I Wu).
v4: make them virtio-private instead of generic helpers.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 drivers/gpu/drm/virtio/virtgpu_drv.h | 17 ++++++
 drivers/gpu/drm/virtio/virtgpu_gem.c | 83 ++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 07f6001ea91e..abb078a5dedf 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h

@@ -84,6 +84,12 @@ struct virtio_gpu_object {
 #define gem_to_virtio_gpu_obj(gobj) \
        container_of((gobj), struct virtio_gpu_object, gem_base)

+struct virtio_gpu_object_array {
+       struct ww_acquire_ctx ticket;
+       u32 nents, total;
+       struct drm_gem_object *objs[];
+};
+
 struct virtio_gpu_vbuffer;
 struct virtio_gpu_device;

@@ -251,6 +257,17 @@ int virtio_gpu_mode_dumb_mmap(struct drm_file *file_priv,
                              struct drm_device *dev,
                              uint32_t handle, uint64_t *offset_p);

+struct virtio_gpu_object_array *virtio_gpu_array_alloc(u32 nents);
+struct virtio_gpu_object_array*
+virtio_gpu_array_from_handles(struct drm_file *drm_file, u32 *handles, u32 nents);
+void virtio_gpu_array_add_obj(struct virtio_gpu_object_array *objs,
+                             struct drm_gem_object *obj);
+int virtio_gpu_array_lock_resv(struct virtio_gpu_object_array *objs);
+void virtio_gpu_array_unlock_resv(struct virtio_gpu_object_array *objs);
+void virtio_gpu_array_add_fence(struct virtio_gpu_object_array *objs,
+                               struct dma_fence *fence);
+void virtio_gpu_array_put_free(struct virtio_gpu_object_array *objs);
+
 /* virtio vg */
 int virtio_gpu_alloc_vbufs(struct virtio_gpu_device *vgdev);
 void virtio_gpu_free_vbufs(struct virtio_gpu_device *vgdev);

diff --git a/drivers/gpu/drm/virtio/virtgpu_gem.c b/drivers/gpu/drm/virtio/virtgpu_gem.c
index 9c9ad3b14080..e88df5e06d06 100644
--- a/drivers/gpu/drm/virtio/virtgpu_gem.c
+++ b/drivers/gpu/drm/virtio/virtgpu_gem.c

@@ -169,3 +169,86 @@ void virtio_gpu_gem_object_close(struct drm_gem_object *obj,
                                                qobj->hw_res_handle);
        virtio_gpu_object_unreserve(qobj);
 }
+
+struct virtio_gpu_object_array *virtio_gpu_array_alloc(u32 nents)
+{
+       struct virtio_gpu_object_array *objs;
+       size_t size = sizeof(*objs) + sizeof(objs->objs[0]) * nents;
+
+       objs = kmalloc(size, GFP_KERNEL);
+       if (!objs)
+               return NULL;
+
+       objs->nents = 0;
+       objs->total = nents;
+       return objs;
+}
+
+static void virtio_gpu_array_free(struct virtio_gpu_object_array *objs)
+{
+       kfree(objs);
+}
+
+struct virtio_gpu_object_array*
+virtio_gpu_array_from_handles(struct drm_file *drm_file, u32 *handles, u32 nents)
+{
+       struct virtio_gpu_object_array *objs;
+       u32 i;
+
+       objs = virtio_gpu_array_alloc(nents);
+       if (!objs)
+               return NULL;
+
+       for (i = 0; i < nents; i++) {
+               objs->nents = i;