From 84a78a06789e69d3945178d05c2030e68549d72f Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Fri, 24 Apr 2020 19:11:42 +0300 Subject: [PATCH] dmaengine: dmatest: Fix iteration non-stop logic BugLink: https://bugs.launchpad.net/bugs/1878256 commit b9f960201249f20deea586b4ec814669b4c6b1c0 upstream. 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 Cc: Nicolas Ferre Signed-off-by: Andy Shevchenko Acked-by: Nicolas Ferre Link: https://lore.kernel.org/r/20200424161147.16895-1-andriy.shevchenko@linux.intel.com Signed-off-by: Vinod Koul Signed-off-by: Greg Kroah-Hartman Signed-off-by: Kamal Mostafa Signed-off-by: Stefan Bader --- 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 e39336127741..d19a602beebd 100644 --- a/drivers/dma/dmatest.c +++ b/drivers/dma/dmatest.c @@ -552,8 +552,8 @@ 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]; -- 2.39.5