dmaengine: fix dmatest to verify minimum transfer length and test buffer size

Transfers and the test buffer have to be at least align bytes long.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c
index a32a4cf7b1e0..8b905161fbf4 100644
--- a/drivers/dma/dmatest.c
+++ b/drivers/dma/dmatest.c
@@ -298,10 +298,6 @@ static int dmatest_func(void *data)
 
                 total_tests++;
 
-                len = dmatest_random() % test_buf_size + 1;
-                src_off = dmatest_random() % (test_buf_size - len + 1);
-                dst_off = dmatest_random() % (test_buf_size - len + 1);
-
                 /* honor alignment restrictions */
                 if (thread->type == DMA_MEMCPY)
                         align = dev->copy_align;
@@ -310,7 +306,19 @@ static int dmatest_func(void *data)
                 else if (thread->type == DMA_PQ)
                         align = dev->pq_align;
 
+                if (1 << align > test_buf_size) {
+                        pr_err("%u-byte buffer too small for %d-byte alignment\n",
+                               test_buf_size, 1 << align);
+                        break;
+                }
+
+                len = dmatest_random() % test_buf_size + 1;
                 len = (len >> align) << align;
+                if (!len)
+                        len = 1 << align;
+                src_off = dmatest_random() % (test_buf_size - len + 1);
+                dst_off = dmatest_random() % (test_buf_size - len + 1);
+
                 src_off = (src_off >> align) << align;
                 dst_off = (dst_off >> align) << align;