drm/nouveau: omit to create schedulers using the legacy uAPI

Omit to create scheduler instances when using the legacy uAPI. When
using the legacy NOUVEAU_GEM_PUSHBUF ioctl no scheduler instance is
required, hence omit creating scheduler instances in
nouveau_abi16_ioctl_channel_alloc().
Tested-by: Timur Tabi <ttabi@nvidia.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240202000606.3526-2-dakr@redhat.com

drivers/gpu/drm/nouveau/nouveau_abi16.c

@@ -339,10 +339,16 @@ nouveau_abi16_ioctl_channel_alloc(ABI16_IOCTL_ARGS)
 	if (ret)
 		goto done;
 
-	ret = nouveau_sched_create(&chan->sched, drm, drm->sched_wq,
-				   chan->chan->dma.ib_max);
-	if (ret)
-		goto done;
+	/* If we're not using the VM_BIND uAPI, we don't need a scheduler.
+	 *
+	 * The client lock is already acquired by nouveau_abi16_get().
+	 */
+	if (nouveau_cli_uvmm(cli)) {
+		ret = nouveau_sched_create(&chan->sched, drm, drm->sched_wq,
+					   chan->chan->dma.ib_max);
+		if (ret)
+			goto done;
+	}
 
 	init->channel = chan->chan->chid;