On 24-04-20, 19:11, Andy Shevchenko wrote:
> 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@xxxxxxxxxxx>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> 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 4993e3e5c5b01..307622e765996 100644
> --- a/drivers/dma/dmatest.c
> +++ b/drivers/dma/dmatest.c
> @@ -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;
> }
> }
> @@ -1192,7 +1192,7 @@ static int dmatest_chan_set(const char *val, const struct kernel_param *kp)
> mutex_unlock(&info->lock);
> return ret;
> }
> - /*Clear any previously run threads */
> + /* Clear any previously run threads */
This does not belong to this patch, can you please split it out...
--
~Vinod
