virtio: Rework virtio_gpu_object_kmap()

Currently, virtio_gpu_object_kmap() is only called by
virtio_gpufb_create(), when a DRM framebuffer is created.

Thus, instead of returning the vmap'ed address, emit a warning
if virtio_gpu_object_kmap is called on an already mapped
object. With this change, kmap/kunmap calls are now balanced.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20180925161606.17980-3-ezequiel@collabora.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

3 files changed, 6 insertions, 17 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 6669bf4c4ca3..d29f0c7c768c 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -364,7 +364,7 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
                              unsigned long size, bool kernel, bool pinned,
                              struct virtio_gpu_object **bo_ptr);
 void virtio_gpu_object_kunmap(struct virtio_gpu_object *bo);
-int virtio_gpu_object_kmap(struct virtio_gpu_object *bo, void **ptr);
+int virtio_gpu_object_kmap(struct virtio_gpu_object *bo);
 int virtio_gpu_object_get_sg_table(struct virtio_gpu_device *qdev,
                                    struct virtio_gpu_object *bo);
 void virtio_gpu_object_free_sg_table(struct virtio_gpu_object *bo);
diff --git a/drivers/gpu/drm/virtio/virtgpu_fb.c b/drivers/gpu/drm/virtio/virtgpu_fb.c
index e1e41efabec1..cea749f4ec39 100644
--- a/drivers/gpu/drm/virtio/virtgpu_fb.c
+++ b/drivers/gpu/drm/virtio/virtgpu_fb.c
@@ -203,12 +203,6 @@ static struct fb_ops virtio_gpufb_ops = {
         .fb_imageblit = virtio_gpu_3d_imageblit,
 };
 
-static int virtio_gpu_vmap_fb(struct virtio_gpu_device *vgdev,
-                              struct virtio_gpu_object *obj)
-{
-        return virtio_gpu_object_kmap(obj, NULL);
-}
-
 static int virtio_gpufb_create(struct drm_fb_helper *helper,
                                struct drm_fb_helper_surface_size *sizes)
 {
@@ -241,9 +235,9 @@ static int virtio_gpufb_create(struct drm_fb_helper *helper,
         virtio_gpu_cmd_create_resource(vgdev, resid, format,
                                        mode_cmd.width, mode_cmd.height);
 
-        ret = virtio_gpu_vmap_fb(vgdev, obj);
+        ret = virtio_gpu_object_kmap(obj);
         if (ret) {
-                DRM_ERROR("failed to vmap fb %d\n", ret);
+                DRM_ERROR("failed to kmap fb %d\n", ret);
                 goto err_obj_vmap;
         }
 
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 113eae00d293..eca765537470 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -107,22 +107,17 @@ void virtio_gpu_object_kunmap(struct virtio_gpu_object *bo)
         ttm_bo_kunmap(&bo->kmap);
 }
 
-int virtio_gpu_object_kmap(struct virtio_gpu_object *bo, void **ptr)
+int virtio_gpu_object_kmap(struct virtio_gpu_object *bo)
 {
         bool is_iomem;
         int r;
 
-        if (bo->vmap) {
-                if (ptr)
-                        *ptr = bo->vmap;
-                return 0;
-        }
+        WARN_ON(bo->vmap);
+
         r = ttm_bo_kmap(&bo->tbo, 0, bo->tbo.num_pages, &bo->kmap);
         if (r)
                 return r;
         bo->vmap = ttm_kmap_obj_virtual(&bo->kmap, &is_iomem);
-        if (ptr)
-                *ptr = bo->vmap;
         return 0;
 }