drm: virtio: use kmem_cache

Just use kmem_cache instead of rolling
our own, limited implementation.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1488377348-5006-1-git-send-email-kraxel@redhat.com

drivers/gpu/drm/virtio/virtgpu_drv.h

@@ -178,9 +178,7 @@ struct virtio_gpu_device {
 
 	struct virtio_gpu_queue ctrlq;
 	struct virtio_gpu_queue cursorq;
-	struct list_head free_vbufs;
-	spinlock_t free_vbufs_lock;
-	void *vbufs;
+	struct kmem_cache *vbufs;
 	bool vqs_ready;
 
 	struct idr	resource_idr;

drivers/gpu/drm/virtio/virtgpu_vq.c

@@ -74,51 +74,19 @@ void virtio_gpu_cursor_ack(struct virtqueue *vq)
 
 int virtio_gpu_alloc_vbufs(struct virtio_gpu_device *vgdev)
 {
-	struct virtio_gpu_vbuffer *vbuf;
-	int i, size, count = 16;
-	void *ptr;
-
-	INIT_LIST_HEAD(&vgdev->free_vbufs);
-	spin_lock_init(&vgdev->free_vbufs_lock);
-	count += virtqueue_get_vring_size(vgdev->ctrlq.vq);
-	count += virtqueue_get_vring_size(vgdev->cursorq.vq);
-	size = count * VBUFFER_SIZE;
-	DRM_INFO("virtio vbuffers: %d bufs, %zdB each, %dkB total.\n",
-		 count, VBUFFER_SIZE, size / 1024);
-
-	vgdev->vbufs = kzalloc(size, GFP_KERNEL);
+	vgdev->vbufs = kmem_cache_create("virtio-gpu-vbufs",
+					 VBUFFER_SIZE,
+					 __alignof__(struct virtio_gpu_vbuffer),
+					 0, NULL);
 	if (!vgdev->vbufs)
 		return -ENOMEM;
-
-	for (i = 0, ptr = vgdev->vbufs;
-	     i < count;
-	     i++, ptr += VBUFFER_SIZE) {
-		vbuf = ptr;
-		list_add(&vbuf->list, &vgdev->free_vbufs);
-	}
 	return 0;
 }
 
 void virtio_gpu_free_vbufs(struct virtio_gpu_device *vgdev)
 {
-	struct virtio_gpu_vbuffer *vbuf;
-	int i, count = 0;
-
-	count += virtqueue_get_vring_size(vgdev->ctrlq.vq);
-	count += virtqueue_get_vring_size(vgdev->cursorq.vq);
-
-	spin_lock(&vgdev->free_vbufs_lock);
-	for (i = 0; i < count; i++) {
-		if (WARN_ON(list_empty(&vgdev->free_vbufs))) {
-			spin_unlock(&vgdev->free_vbufs_lock);
-			return;
-		}
-		vbuf = list_first_entry(&vgdev->free_vbufs,
-					struct virtio_gpu_vbuffer, list);
-		list_del(&vbuf->list);
-	}
-	spin_unlock(&vgdev->free_vbufs_lock);
-	kfree(vgdev->vbufs);
+	kmem_cache_destroy(vgdev->vbufs);
+	vgdev->vbufs = NULL;
 }
 
 static struct virtio_gpu_vbuffer*
@@ -128,12 +96,9 @@ virtio_gpu_get_vbuf(struct virtio_gpu_device *vgdev,
 {
 	struct virtio_gpu_vbuffer *vbuf;
 
-	spin_lock(&vgdev->free_vbufs_lock);
-	BUG_ON(list_empty(&vgdev->free_vbufs));
-	vbuf = list_first_entry(&vgdev->free_vbufs,
-				struct virtio_gpu_vbuffer, list);
-	list_del(&vbuf->list);
-	spin_unlock(&vgdev->free_vbufs_lock);
+	vbuf = kmem_cache_alloc(vgdev->vbufs, GFP_KERNEL);
+	if (IS_ERR(vbuf))
+		return ERR_CAST(vbuf);
 	memset(vbuf, 0, VBUFFER_SIZE);
 
 	BUG_ON(size > MAX_INLINE_CMD_SIZE);
@@ -208,9 +173,7 @@ static void free_vbuf(struct virtio_gpu_device *vgdev,
 	if (vbuf->resp_size > MAX_INLINE_RESP_SIZE)
 		kfree(vbuf->resp_buf);
 	kfree(vbuf->data_buf);
-	spin_lock(&vgdev->free_vbufs_lock);
-	list_add(&vbuf->list, &vgdev->free_vbufs);
-	spin_unlock(&vgdev->free_vbufs_lock);
+	kmem_cache_free(vgdev->vbufs, vbuf);
 }
 
 static void reclaim_vbufs(struct virtqueue *vq, struct list_head *reclaim_list)