]> git.itanic.dy.fi Git - linux-stable/commit
dmaengine: dmatest: Fix iteration non-stop logic
authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Fri, 24 Apr 2020 16:11:42 +0000 (19:11 +0300)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Tue, 5 May 2020 17:14:40 +0000 (19:14 +0200)
commite66e9687af44de166fa9b7c079cc34b41a742577
treeedd76c8c20b680498ab7fbe96e775b9398da7c0c
parentf92f2904141cc2055ee01d2a979a1737f31d3284
dmaengine: dmatest: Fix iteration non-stop logic

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 <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>
drivers/dma/dmatest.c