From: Andy Shevchenko andriy.shevchenko@linux.intel.com
[ Upstream commit b9f960201249f20deea586b4ec814669b4c6b1c0 ]
Under some circumstances, i.e. when test is still running and about to time out and user runs, for example,
grep -H . /sys/module/dmatest/parameters/*
the iterations parameter is not respected and test is going on and on until user gives
echo 0 > /sys/module/dmatest/parameters/run
This is not what expected.
The history of this bug is interesting. I though that the commit 2d88ce76eb98 ("dmatest: add a 'wait' parameter") is a culprit, but looking closer to the code I think it simple revealed the broken logic from the day one, i.e. in the commit 0a2ff57d6fba ("dmaengine: dmatest: add a maximum number of test iterations") which adds iterations parameter.
So, to the point, the conditional of checking the thread to be stopped being first part of conjunction logic prevents to check iterations. Thus, we have to always check both conditions to be able to stop after given iterations.
Since it wasn't visible before second commit appeared, I add a respective Fixes tag.
Fixes: 2d88ce76eb98 ("dmatest: add a 'wait' parameter") Cc: Dan Williams dan.j.williams@intel.com Cc: Nicolas Ferre nicolas.ferre@microchip.com Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Acked-by: Nicolas Ferre nicolas.ferre@microchip.com Link: https://lore.kernel.org/r/20200424161147.16895-1-andriy.shevchenko@linux.int... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/dma/dmatest.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/dmatest.c b/drivers/dma/dmatest.c index 7dd46cf5ed845..7a028b57a7efb 100644 --- a/drivers/dma/dmatest.c +++ b/drivers/dma/dmatest.c @@ -505,8 +505,8 @@ static int dmatest_func(void *data) flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;
ktime = ktime_get(); - while (!kthread_should_stop() - && !(params->iterations && total_tests >= params->iterations)) { + while (!(kthread_should_stop() || + (params->iterations && total_tests >= params->iterations))) { struct dma_async_tx_descriptor *tx = NULL; struct dmaengine_unmap_data *um; dma_addr_t srcs[src_cnt];