[PATCH v19 19/30] drm/virtio: Explicitly get and put drm-shmem pages

[Dmitry Osipenko]

We're moving away from implicit get_pages() that is done by
get_pages_sgt() to simplify the refcnt handling. Drivers will have
to pin pages while they use sgt. VirtIO-GPU doesn't support shrinker,
hence pages are pinned and sgt is valid as long as pages' use-count > 0.

Reviewed-by: Boris Brezillon <boris.brezil...@collabora.com>
Signed-off-by: Dmitry Osipenko <dmitry.osipe...@collabora.com>
---
 drivers/gpu/drm/virtio/virtgpu_object.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c 
b/drivers/gpu/drm/virtio/virtgpu_object.c
index c7e74cf13022..e58528c562ef 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -67,6 +67,7 @@ void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo)
 
        virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
        if (virtio_gpu_is_shmem(bo)) {
+               drm_gem_shmem_put_pages(&bo->base);
                drm_gem_shmem_free(&bo->base);
        } else if (virtio_gpu_is_vram(bo)) {
                struct virtio_gpu_object_vram *vram = to_virtio_gpu_vram(bo);
@@ -196,9 +197,13 @@ int virtio_gpu_object_create(struct virtio_gpu_device 
*vgdev,
                return PTR_ERR(shmem_obj);
        bo = gem_to_virtio_gpu_obj(&shmem_obj->base);
 
+       ret = drm_gem_shmem_get_pages(shmem_obj);
+       if (ret)
+               goto err_free_gem;
+
        ret = virtio_gpu_resource_id_get(vgdev, &bo->hw_res_handle);
        if (ret < 0)
-               goto err_free_gem;
+               goto err_put_pages;
 
        bo->dumb = params->dumb;
 
@@ -243,6 +248,8 @@ int virtio_gpu_object_create(struct virtio_gpu_device 
*vgdev,
        kvfree(ents);
 err_put_id:
        virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
+err_put_pages:
+       drm_gem_shmem_put_pages(shmem_obj);
 err_free_gem:
        drm_gem_shmem_free(shmem_obj);
        return ret;
-- 
2.43.0