Re: [Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
On 03/26/2012 11:38 AM, Wolfgang Grandegger wrote: > Hi Gilles, > > On 03/23/2012 02:14 PM, Gilles Chanteperdrix wrote: >> On 03/23/2012 10:59 AM, Gilles Chanteperdrix wrote: >>> On 03/23/2012 09:35 AM, Wolfgang Grandegger wrote: Hello, while playing with rt_pipe, I realized that a select()/poll() function does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the other end. I think this is because the poll callback does not support POLLHUP: http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 Is this by purpose? At least a blocking read() works as expected. It does unblock and return 0 in that case. >>> >>> rt_pipes are deprecated, we are not going to add new features to them >>> now. Please do not use them for new developments. We now have socket >>> based RTIPCs. See examples/rtdm/profiles/ipc. > > Ah, I was not aware of that. This solution does also work for any skin > (and does not require to misuse the native skin any more). > >> On the other hand, if you have a small patch to fix this, I will not >> hurt anyone to merge it. > > OK. See patch below. Merged, thanks. -- Gilles. ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
Re: [Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
On 03/26/2012 11:53 AM, Gilles Chanteperdrix wrote: > On 03/26/2012 11:48 AM, Wolfgang Grandegger wrote: >> On 03/26/2012 11:38 AM, Wolfgang Grandegger wrote: >>> Hi Gilles, >>> >>> On 03/23/2012 02:14 PM, Gilles Chanteperdrix wrote: On 03/23/2012 10:59 AM, Gilles Chanteperdrix wrote: > On 03/23/2012 09:35 AM, Wolfgang Grandegger wrote: >> Hello, >> >> while playing with rt_pipe, I realized that a select()/poll() function >> does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the >> other end. I think this is because the poll callback does not support >> POLLHUP: >> >> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 >> >> Is this by purpose? At least a blocking read() works as expected. It >> does unblock and return 0 in that case. > > rt_pipes are deprecated, we are not going to add new features to them > now. Please do not use them for new developments. We now have socket > based RTIPCs. See examples/rtdm/profiles/ipc. >>> >>> Ah, I was not aware of that. This solution does also work for any skin >>> (and does not require to misuse the native skin any more). At a closer look to the RTIPC interfaces I realized, that they are also based on "xnpipe", like "rt_pipe". Therefore a patch for the "EOF issue" is also here required. >> BTW, is there another interface (whith less overhead) to signal Linux >> thread from RT threads to trigger some work, e.g. for reading from shmem? > > The simplest thing to do in such a case is to make the "Linux" thread a > Xenomai thread but running with the SCHED_OTHER policy, you can then use > simpler IPCs such as semaphores. Starting with Xenomai 2.6.0, such a > thread is guaranteed to return to secondary mode as soon as possible. OK. Wolfgang. ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
Re: [Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
On 03/26/2012 11:48 AM, Wolfgang Grandegger wrote: > On 03/26/2012 11:38 AM, Wolfgang Grandegger wrote: >> Hi Gilles, >> >> On 03/23/2012 02:14 PM, Gilles Chanteperdrix wrote: >>> On 03/23/2012 10:59 AM, Gilles Chanteperdrix wrote: On 03/23/2012 09:35 AM, Wolfgang Grandegger wrote: > Hello, > > while playing with rt_pipe, I realized that a select()/poll() function > does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the > other end. I think this is because the poll callback does not support > POLLHUP: > > http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 > > Is this by purpose? At least a blocking read() works as expected. It > does unblock and return 0 in that case. rt_pipes are deprecated, we are not going to add new features to them now. Please do not use them for new developments. We now have socket based RTIPCs. See examples/rtdm/profiles/ipc. >> >> Ah, I was not aware of that. This solution does also work for any skin >> (and does not require to misuse the native skin any more). > > BTW, is there another interface (whith less overhead) to signal Linux > thread from RT threads to trigger some work, e.g. for reading from shmem? The simplest thing to do in such a case is to make the "Linux" thread a Xenomai thread but running with the SCHED_OTHER policy, you can then use simpler IPCs such as semaphores. Starting with Xenomai 2.6.0, such a thread is guaranteed to return to secondary mode as soon as possible. -- Gilles. ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
Re: [Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
On 03/26/2012 11:38 AM, Wolfgang Grandegger wrote: > Hi Gilles, > > On 03/23/2012 02:14 PM, Gilles Chanteperdrix wrote: >> On 03/23/2012 10:59 AM, Gilles Chanteperdrix wrote: >>> On 03/23/2012 09:35 AM, Wolfgang Grandegger wrote: Hello, while playing with rt_pipe, I realized that a select()/poll() function does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the other end. I think this is because the poll callback does not support POLLHUP: http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 Is this by purpose? At least a blocking read() works as expected. It does unblock and return 0 in that case. >>> >>> rt_pipes are deprecated, we are not going to add new features to them >>> now. Please do not use them for new developments. We now have socket >>> based RTIPCs. See examples/rtdm/profiles/ipc. > > Ah, I was not aware of that. This solution does also work for any skin > (and does not require to misuse the native skin any more). BTW, is there another interface (whith less overhead) to signal Linux thread from RT threads to trigger some work, e.g. for reading from shmem? Wolfgang. ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
Re: [Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
Hi Gilles, On 03/23/2012 02:14 PM, Gilles Chanteperdrix wrote: > On 03/23/2012 10:59 AM, Gilles Chanteperdrix wrote: >> On 03/23/2012 09:35 AM, Wolfgang Grandegger wrote: >>> Hello, >>> >>> while playing with rt_pipe, I realized that a select()/poll() function >>> does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the >>> other end. I think this is because the poll callback does not support >>> POLLHUP: >>> >>> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 >>> >>> Is this by purpose? At least a blocking read() works as expected. It >>> does unblock and return 0 in that case. >> >> rt_pipes are deprecated, we are not going to add new features to them >> now. Please do not use them for new developments. We now have socket >> based RTIPCs. See examples/rtdm/profiles/ipc. Ah, I was not aware of that. This solution does also work for any skin (and does not require to misuse the native skin any more). > On the other hand, if you have a small patch to fix this, I will not > hurt anyone to merge it. OK. See patch below. Wolfgang. >From 49eeb2b8451a68d10a7f1768e2bf74dcdaf3e35e Mon Sep 17 00:00:00 2001 From: Wolfgang Grandegger Date: Mon, 26 Mar 2012 09:21:51 +0200 Subject: [PATCH] nucleus: fix poll EOF issue with xnpipe/rt_pipe So far, the EOF event is not handled in the Linux poll function of the xnpipe/rt_pipe service when the pipe is closed (via rt_pipde_delete). This patch fixes the issue by setting POLLUP in the Linux poll function when the pipe is broken. The subsequent reads will then fail with errno EPIPE. Signed-off-by: Wolfgang Grandegger --- ksrc/nucleus/pipe.c |2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/ksrc/nucleus/pipe.c b/ksrc/nucleus/pipe.c index 1e6bcf2..1d5e39a 100644 --- a/ksrc/nucleus/pipe.c +++ b/ksrc/nucleus/pipe.c @@ -1033,6 +1033,8 @@ static unsigned xnpipe_poll(struct file *file, poll_table *pt) if (testbits(state->status, XNPIPE_KERN_CONN)) w_mask |= (POLLOUT | POLLWRNORM); + else + r_mask |= POLLHUP; if (!emptyq_p(&state->outq)) r_mask |= (POLLIN | POLLRDNORM); -- 1.7.7.6 ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
Re: [Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
On 03/23/2012 10:59 AM, Gilles Chanteperdrix wrote: > On 03/23/2012 09:35 AM, Wolfgang Grandegger wrote: >> Hello, >> >> while playing with rt_pipe, I realized that a select()/poll() function >> does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the >> other end. I think this is because the poll callback does not support >> POLLHUP: >> >> http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 >> >> Is this by purpose? At least a blocking read() works as expected. It >> does unblock and return 0 in that case. > > rt_pipes are deprecated, we are not going to add new features to them > now. Please do not use them for new developments. We now have socket > based RTIPCs. See examples/rtdm/profiles/ipc. > On the other hand, if you have a small patch to fix this, I will not hurt anyone to merge it. -- Gilles. ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
Re: [Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
On 03/23/2012 09:35 AM, Wolfgang Grandegger wrote: > Hello, > > while playing with rt_pipe, I realized that a select()/poll() function > does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the > other end. I think this is because the poll callback does not support > POLLHUP: > > http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 > > Is this by purpose? At least a blocking read() works as expected. It > does unblock and return 0 in that case. rt_pipes are deprecated, we are not going to add new features to them now. Please do not use them for new developments. We now have socket based RTIPCs. See examples/rtdm/profiles/ipc. -- Gilles. ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
[Xenomai-help] rt_pipe does not support POLLHUP on the Linux side
Hello, while playing with rt_pipe, I realized that a select()/poll() function does not unblock when the rt_pipe is deleted (via rt_pipe_delete) on the other end. I think this is because the poll callback does not support POLLHUP: http://www.rts.uni-hannover.de/xenomai/lxr/source/ksrc/nucleus/pipe.c#1024 Is this by purpose? At least a blocking read() works as expected. It does unblock and return 0 in that case. Wolfgang. ___ Xenomai-help mailing list Xenomai-help@gna.org https://mail.gna.org/listinfo/xenomai-help
