media: mediatek: vcodec: Fix H264 stateless decoder smatch warning

[ Upstream commit 7878d3a ]

Fix a smatch static checker warning on vdec_h264_req_if.c.
Which leads to a kernel crash when fb is NULL.

Fixes: 06fa5f7 ("media: mtk-vcodec: vdec: support stateless H.264 decoding")
Signed-off-by: Yunfei Dong <yunfei.dong@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Sebastian Fricke <sebastian.fricke@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: yunfei-mtk

drivers/media/platform/mediatek/vcodec/decoder/vdec/vdec_h264_req_if.c

@@ -347,11 +347,16 @@ static int vdec_h264_slice_decode(void *h_vdec, struct mtk_vcodec_mem *bs,
 		return vpu_dec_reset(vpu);
 
 	fb = inst->ctx->dev->vdec_pdata->get_cap_buffer(inst->ctx);
+	if (!fb) {
+		mtk_vdec_err(inst->ctx, "fb buffer is NULL");
+		return -ENOMEM;
+	}
+
 	src_buf_info = container_of(bs, struct mtk_video_dec_buf, bs_buffer);
 	dst_buf_info = container_of(fb, struct mtk_video_dec_buf, frame_buffer);
 
-	y_fb_dma = fb ? (u64)fb->base_y.dma_addr : 0;
-	c_fb_dma = fb ? (u64)fb->base_c.dma_addr : 0;
+	y_fb_dma = fb->base_y.dma_addr;
+	c_fb_dma = fb->base_c.dma_addr;
 
 	mtk_vdec_debug(inst->ctx, "+ [%d] FB y_dma=%llx c_dma=%llx va=%p",
 		       inst->num_nalu, y_fb_dma, c_fb_dma, fb);