[PATCH 4.7 010/141] drm/nouveau/fifo/nv04: avoid ramht race against cookie insertion

[Greg Kroah-Hartman]

4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ilia Mirkin <imirkin@xxxxxxxxxxxx>

commit 666ca3d8f19082f40745d75f3cc7cc0200ee87e3 upstream.

Signed-off-by: Ilia Mirkin <imirkin@xxxxxxxxxxxx>
Signed-off-by: Ben Skeggs <bskeggs@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/gpu/drm/nouveau/nvkm/engine/fifo/dmanv04.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/nouveau/nvkm/engine/fifo/dmanv04.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/fifo/dmanv04.c
@@ -37,7 +37,10 @@ nv04_fifo_dma_object_dtor(struct nvkm_fi
 {
 	struct nv04_fifo_chan *chan = nv04_fifo_chan(base);
 	struct nvkm_instmem *imem = chan->fifo->base.engine.subdev.device->imem;
+
+	mutex_lock(&chan->fifo->base.engine.subdev.mutex);
 	nvkm_ramht_remove(imem->ramht, cookie);
+	mutex_unlock(&chan->fifo->base.engine.subdev.mutex);
 }
 
 static int