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dmaengine: dmatest: Fix process hang when reading 'wait' parameter

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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 6138f967bc

  ("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: 6138f967bc ("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.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Andy Shevchenko 2020-04-28 14:35:18 +03:00 committed by Vinod Koul
parent b9f9602012
commit aa72f1d20e
1 changed files with 1 additions and 1 deletions
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2
drivers/dma/dmatest.c
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@ -240,7 +240,7 @@ static bool is_threaded_test_run(struct dmatest_info *info)
struct dmatest_thread *thread;
list_for_each_entry(thread, &dtc->threads, node) {
if (!thread->done)
if (!thread->done && !thread->pending)
return true;
}
}