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dmaengine: dmatest: Fix iteration non-stop logic

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commit b9f9602012 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
  2d88ce76eb ("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
  0a2ff57d6f ("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: 2d88ce76eb ("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.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andy Shevchenko
2020-04-24 19:11:42 +03:00
committed by Chris
parent 9a62af2a6b
commit 6daa34b9f7
1 changed files with 2 additions and 2 deletions
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4
drivers/dma/dmatest.c
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@@ -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];