Andy Shevchenko authored Jan 30, 2019 and Vinod Koul committed Feb 04, 2019

In case of mapping error the DMA addresses are invalid and continuing
will screw system memory or potentially something else.

[  222.480310] dmatest: dma0chan7-copy0: summary 1 tests, 3 failures 6 iops 349 KB/s (0)
...
[  240.912725] check: Corrupted low memory at 00000000c7c75ac9 (2940 phys) = 5656000000000000
[  240.921998] check: Corrupted low memory at 000000005715a1cd (2948 phys) = 279f2aca5595ab2b
[  240.931280] check: Corrupted low memory at 000000002f4024c0 (2950 phys) = 5e5624f349e793cf
...

Abort any test if mapping failed.

Fixes: 4076e755

 ("dmatest: convert to dmaengine_unmap_data")
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>