From: Andy Shevchenko andriy.shevchenko@linux.intel.com
commit aa72f1d20ee973d68f26d46fce5e1cf6f9b7e1ca upstream.
If we do
% echo 1 > /sys/module/dmatest/parameters/run [ 115.851124] dmatest: Could not start test, no channels configured
% echo dma8chan7 > /sys/module/dmatest/parameters/channel [ 127.563872] dmatest: Added 1 threads using dma8chan7
% cat /sys/module/dmatest/parameters/wait ... !!! HANG !!! ...
The culprit is the commit 6138f967bccc
("dmaengine: dmatest: Use fixed point div to calculate iops")
which makes threads not to run, but pending and being kicked off by writing to the 'run' node. However, it forgot to consider 'wait' routine to avoid above mentioned case.
In order to fix this, check for really running threads, i.e. with pending and done flags unset.
It's pity the culprit commit hadn't updated documentation and tested all possible scenarios.
Fixes: 6138f967bccc ("dmaengine: dmatest: Use fixed point div to calculate iops") Cc: Seraj Alijan seraj.alijan@sondrel.com Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Link: https://lore.kernel.org/r/20200428113518.70620-1-andriy.shevchenko@linux.int... Signed-off-by: Vinod Koul vkoul@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/dma/dmatest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/dma/dmatest.c +++ b/drivers/dma/dmatest.c @@ -240,7 +240,7 @@ static bool is_threaded_test_run(struct struct dmatest_thread *thread;
list_for_each_entry(thread, &dtc->threads, node) { - if (!thread->done) + if (!thread->done && !thread->pending) return true; } }