Re: [PATCH 2/5] Make RTDM tasks behave, part I

[Philippe Gerum <rpm@xenomai.org>]

Richard Weinberger <richard@nod.at> writes:

> RTDM tasks must now utilize rtdm_task_should_stop() to ensure proper
> cleanup and SIGSHADOW detection.
> Also, handle -EINTR gracefully, rather than exiting immediately on
> interruption, the task should loop and re-check rtdm_task_should_stop()
> to decide if termination is actually required.
>
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
>  kernel/drivers/autotune/autotune.c              | 17 ++++++++++-------
>  kernel/drivers/net/addons/proxy.c               |  6 +++++-
>  kernel/drivers/net/stack/ipv4/tcp/timerwheel.c  |  6 ++++--
>  kernel/drivers/net/stack/rtcfg/rtcfg_frame.c    |  6 +++++-
>  .../drivers/net/stack/rtmac/nomac/nomac_proto.c |  6 +++++-
>  .../drivers/net/stack/rtmac/tdma/tdma_worker.c  |  4 +++-
>  kernel/drivers/net/stack/rtnet_rtpc.c           |  5 ++++-
>  kernel/drivers/net/stack/stack_mgr.c            |  6 +++++-
>  kernel/drivers/testing/rtdmtest.c               |  9 ++++-----
>  kernel/drivers/testing/timerbench.c             |  2 +-
>  10 files changed, 46 insertions(+), 21 deletions(-)
>
> diff --git a/kernel/drivers/autotune/autotune.c b/kernel/drivers/autotune/autotune.c
> index 03fd688de..c11d18057 100644
> --- a/kernel/drivers/autotune/autotune.c
> +++ b/kernel/drivers/autotune/autotune.c
> @@ -248,22 +248,25 @@ static void task_handler(void *arg)
>  	xnticks_t now;
>  	int ret = 0;
>  
> -	for (;;) {
> -		if (rtdm_task_should_stop())
> -			break;
> -
> +	while (!rtdm_task_should_stop()) {
>  		ret = rtdm_event_wait(&k_tuner->barrier);
> -		if (ret)
> +		if (ret == -EINTR)
> +			continue;

Using -EINTR is going to be a problem if xnthread_unblock() is called to
forcibly wake up a kernel task from a sleep. In this case, you would not
be able to distinguish a signal receipt from a forcible
unblock. -ERESTARTSYS may be better for that specific purpose in the
RTDM API.

-- 
Philippe.