Re: [Xenomai-core] Re: [Xenomai-help] -110 error on rt_task_send... bug?

[Ulrich Schwab <schwab@domain.hid>]

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On Wednesday 09 August 2006 13:42, Dmitry Adamushko wrote:
> So could anyone test this patch and let me know if it works?
>
> Note : I haven't compiled it even as I don't have a proper environment. But
> the changes are pretty simple so it should be ok.
I just did run the test program supplied by Vincent after applying Your patch
(against 2.2.0)
It did work !
Only one small typo was in the patch, it is fixed in the attached patch 
version.

>
> There was actually yet another problem mmm... who cares to delete a sender
> from the msendq?
>
> Now should be ok or maybe I'm completely wrong and see the things which do
> not exist at all :)
>
> p.s. I cc'ed "xenomai-core" as it may involve further discussions and it's
> the right place indeed.

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diff -urp xenomai-a/include/nucleus/synch.h xenomai-b/include/nucleus/synch.h
--- xenomai-a/include/nucleus/synch.h	2006-07-20 11:09:01.000000000 +0200
+++ xenomai-b/include/nucleus/synch.h	2006-08-09 12:53:37.044217000 +0200
@@ -28,6 +28,7 @@
 #define XNSYNCH_NOPIP   0x0
 #define XNSYNCH_PIP     0x2
 #define XNSYNCH_DREORD  0x4
+#define XNSYNCH_FOWNER	0x20	/* Fixed owner */
 
 #if defined(__KERNEL__) || defined(__XENO_SIM__)
 
diff -urp xenomai-a/ksrc/nucleus/synch.c xenomai-b/ksrc/nucleus/synch.c
--- xenomai-a/ksrc/nucleus/synch.c	2006-06-15 14:15:25.000000000 +0200
+++ xenomai-b/ksrc/nucleus/synch.c	2006-08-09 13:28:55.199081000 +0200
@@ -37,6 +37,14 @@
 #include <nucleus/module.h>
 #include <nucleus/ltt.h>
 
+/* temporarily here */
+static inline void xnsynch_set_owner_internal(xnsynch_t *synch, xnthread_t *thread)
+{
+	if (!testbits(synch->status, XNSYNCH_FOWNER))
+		synch->owner = thread;
+}
+
+
 /*! 
  * \fn void xnsynch_init(xnsynch_t *synch, xnflags_t flags);
  * \brief Initialize a synchronization object.
@@ -181,7 +189,7 @@ void xnsynch_sleep_on(xnsynch_t *synch, 
 
 				if (testbits(synch->status, XNSYNCH_PENDING)) {
 					/* Ownership is still pending, steal the resource. */
-					synch->owner = thread;
+					xnsynch_set_owner_internal(synch, thread);
 					__clrbits(thread->status,
 						  XNRMID | XNTIMEO | XNBREAK);
 					goto grab_ownership;
@@ -209,7 +217,7 @@ void xnsynch_sleep_on(xnsynch_t *synch, 
 
 			xnpod_suspend_thread(thread, XNPEND, timeout, synch);
 
-			if (unlikely(synch->owner != thread)) {
+			if (!testbits(synch->status, XNSYNCH_FOWNER) && unlikely(synch->owner != thread)) {
 				/* Somebody stole us the ownership while we were ready to
 				   run, waiting for the CPU: we need to wait again for the
 				   resource. */
@@ -362,12 +370,12 @@ xnthread_t *xnsynch_wakeup_one_sleeper(x
 	if (holder) {
 		thread = link2thread(holder, plink);
 		thread->wchan = NULL;
-		synch->owner = thread;
+		xnsynch_set_owner_internal(synch, thread);
 		__setbits(synch->status, XNSYNCH_PENDING);
 		xnltt_log_event(xeno_ev_wakeup1, thread->name, synch);
 		xnpod_resume_thread(thread, XNPEND);
 	} else {
-		synch->owner = NULL;
+		xnsynch_set_owner_internal(synch, thread);
 		__clrbits(synch->status, XNSYNCH_PENDING);
 	}
 
@@ -435,7 +443,7 @@ xnpholder_t *xnsynch_wakeup_this_sleeper
 	nholder = poppq(&synch->pendq, holder);
 	thread = link2thread(holder, plink);
 	thread->wchan = NULL;
-	synch->owner = thread;
+	xnsynch_set_owner_internal(synch, thread);
 	__setbits(synch->status, XNSYNCH_PENDING);
 	xnltt_log_event(xeno_ev_wakeupx, thread->name, synch);
 	xnpod_resume_thread(thread, XNPEND);
@@ -523,7 +531,7 @@ int xnsynch_flush(xnsynch_t *synch, xnfl
 		status = XNSYNCH_RESCHED;
 	}
 
-	synch->owner = NULL;
+	xnsynch_set_owner_internal(synch, NULL);
 	__clrbits(synch->status, XNSYNCH_PENDING);
 
 	xnlock_put_irqrestore(&nklock, s);
diff -urp xenomai-a/ksrc/skins/native/task.c xenomai-b/ksrc/skins/native/task.c
--- xenomai-a/ksrc/skins/native/task.c	2006-07-30 10:50:49.000000000 +0200
+++ xenomai-b/ksrc/skins/native/task.c	2006-08-09 13:32:21.917770000 +0200
@@ -262,7 +262,7 @@ int rt_task_create(RT_TASK *task,
 
 #ifdef CONFIG_XENO_OPT_NATIVE_MPS
 	xnsynch_init(&task->mrecv, XNSYNCH_FIFO);
-	xnsynch_init(&task->msendq, XNSYNCH_PRIO | XNSYNCH_PIP);
+	xnsynch_init(&task->msendq, XNSYNCH_PRIO | XNSYNCH_PIP | XNSYNCH_FOWNER);
 	xnsynch_set_owner(&task->msendq, &task->thread_base);
 	task->flowgen = 0;
 #endif /* CONFIG_XENO_OPT_NATIVE_MPS */
@@ -2057,10 +2057,7 @@ int rt_task_reply(int flowid, RT_TASK_MC
 		   identifier from other senders wrt to a given receiver. */
 
 		if (receiver->wait_args.mps.mcb_s.flowid == flowid) {
-			/* Note that the following will cause the receiver to be
-			   unblocked without transferring the ownership of the
-			   msendq object, since we want the sender to keep it. */
-			xnpod_resume_thread(&receiver->thread_base, XNPEND);
+			xnsynch_wakeup_this_sleeper(&sender->msendq, holder);
 			break;
 		}
 	}