dma-mapping: benchmark: avoid needless copy_to_user if benchmark fails

If do_map_benchmark() has failed, there is nothing useful to copy back
to userspace.

Suggested-by: Barry Song <21cnbao@gmail.com>
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

diff --git a/kernel/dma/map_benchmark.c b/kernel/dma/map_benchmark.c
index 2478957cf9f8398a39c87c41df000169705c3f62..a6edb1ef98c8a6725f9119f3fce2825e5d759125 100644 (file)
--- a/kernel/dma/map_benchmark.c
+++ b/kernel/dma/map_benchmark.c
@@ -256,6 +256,9 @@ static long map_benchmark_ioctl(struct file *file, unsigned int cmd,
                 * dma_mask changed by benchmark
                 */
                dma_set_mask(map->dev, old_dma_mask);
+
+               if (ret)
+                       return ret;
                break;
        default:
                return -EINVAL;