media: mediatek: vcodec: Fix VP8 stateless decoder smatch warning

commit b113bc7c0e83b32f4dd2d291a2b6c4803e0a2c44 upstream.

Fix a smatch static checker warning on vdec_vp8_req_if.c.
Which leads to a kernel crash when fb is NULL.

Fixes: 7a7ae26 ("media: mediatek: vcodec: support stateless VP8 decoding")
Signed-off-by: Yunfei Dong <[email protected]>
Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
Signed-off-by: Sebastian Fricke <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>
Signed-off-by: Bin Lan <[email protected]>
Signed-off-by: He Zhe <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: yunfei-mtk

drivers/media/platform/mediatek/vcodec/vdec/vdec_vp8_req_if.c

@@ -336,14 +336,18 @@ static int vdec_vp8_slice_decode(void *h_vdec, struct mtk_vcodec_mem *bs,
 	src_buf_info = container_of(bs, struct mtk_video_dec_buf, bs_buffer);
 
 	fb = inst->ctx->dev->vdec_pdata->get_cap_buffer(inst->ctx);
-	dst_buf_info = container_of(fb, struct mtk_video_dec_buf, frame_buffer);
+	if (!fb) {
+		mtk_vcodec_err(inst, "fb buffer is NULL");
+		return -ENOMEM;
+	}
 
-	y_fb_dma = fb ? (u64)fb->base_y.dma_addr : 0;
+	dst_buf_info = container_of(fb, struct mtk_video_dec_buf, frame_buffer);
+	y_fb_dma = fb->base_y.dma_addr;
 	if (inst->ctx->q_data[MTK_Q_DATA_DST].fmt->num_planes == 1)
 		c_fb_dma = y_fb_dma +
 			inst->ctx->picinfo.buf_w * inst->ctx->picinfo.buf_h;
 	else
-		c_fb_dma = fb ? (u64)fb->base_c.dma_addr : 0;
+		c_fb_dma = fb->base_c.dma_addr;
 
 	inst->vsi->dec.bs_dma = (u64)bs->dma_addr;
 	inst->vsi->dec.bs_sz = bs->size;