freebsd_network: Rewrite ConditionVariable-using code.

The old code was not at all correct with respect to interlocking.
The new code should be, and is also much simpler.

src/libs/compat/freebsd_network/Condvar.cpp

@@ -1,93 +0,0 @@
-/*
- * Copyright 2009 Colin Günther, coling@gmx.de
- * All Rights Reserved. Distributed under the terms of the MIT License.
- */
-
-
-extern "C" {
-#include <compat/sys/condvar.h>
-#include <compat/sys/kernel.h>
-}
-
-#include "Condvar.h"
-
-
-void
-conditionInit(struct cv* variable, const char* description)
-{
-	variable->condition.Init(variable, description);
-}
-
-
-void
-conditionPublish(struct cv* variable, const void* waitChannel,
-	const char* description)
-{
-	variable->condition.Publish(waitChannel, description);
-}
-
-
-void
-conditionUnpublish(struct cv* variable)
-{
-	variable->condition.Unpublish();
-}
-
-
-int
-conditionTimedWait(struct cv* variable, const int timeout)
-{
-	status_t status = variable->condition.Wait(B_RELATIVE_TIMEOUT,
-		TICKS_2_USEC(timeout));
-
-	if (status != B_OK)
-		status = EWOULDBLOCK;
-	return status;
-}
-
-
-void
-conditionWait(struct cv* variable)
-{
-	variable->condition.Wait();
-}
-
-
-void
-conditionNotifyOne(struct cv* variable)
-{
-	variable->condition.NotifyOne();
-}
-
-
-int
-publishedConditionTimedWait(const void* waitChannel, const int timeout)
-{
-	ConditionVariableEntry variableEntry;
-	bigtime_t usecs = TICKS_2_USEC(timeout);
-
-	// FreeBSD has a condition-variable scheduling system with different
-	// scheduling semantics than ours does. As a result, it seems there are
-	// some scenarios which work fine under FreeBSD but race into a deadlock
-	// on Haiku. To avoid this, turn unlimited timeouts into 1sec ones.
-	status_t status = variableEntry.Wait(waitChannel, B_RELATIVE_TIMEOUT,
-		usecs > 0 ? usecs : 1000 * 1000);
-
-	if (status != B_OK)
-		status = EWOULDBLOCK;
-	return status;
-}
-
-
-void
-publishedConditionNotifyAll(const void* waitChannel)
-{
-	ConditionVariable::NotifyAll(waitChannel, B_OK);
-}
-
-
-void
-publishedConditionNotifyOne(const void* waitChannel)
-{
-	ConditionVariable::NotifyOne(waitChannel, B_OK);
-}

src/libs/compat/freebsd_network/Condvar.h

@@ -1,27 +0,0 @@
-/*
- * Copyright 2009 Colin Günther, coling@gmx.de
- * All Rights Reserved. Distributed under the terms of the MIT License.
- */
-#ifndef CONDVAR_H_
-#define CONDVAR_H_
-
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-void conditionInit(struct cv*, const char*);
-void conditionPublish(struct cv*, const void*, const char*);
-void conditionUnpublish(struct cv*);
-int conditionTimedWait(struct cv*, const int);
-void conditionWait(struct cv*);
-void conditionNotifyOne(struct cv*);
-int publishedConditionTimedWait(const void*, const int);
-void publishedConditionNotifyAll(const void*);
-void publishedConditionNotifyOne(const void*);
-
-#ifdef __cplusplus
-}
-#endif
-
-#endif /* CONDVAR_H_ */

src/libs/compat/freebsd_network/Jamfile

@@ -18,8 +18,7 @@ KernelStaticLibrary libfreebsd_network.a :
 	bus_dma.cpp
 	callout.cpp
 	clock.c
-	condvar.c
-	Condvar.cpp
+	condvar.cpp
 	device.c
 	device_hooks.c
 	driver.c
@@ -45,7 +44,7 @@ KernelStaticLibrary libfreebsd_network.a :
 	priv.cpp
 	smp.c
 	subr_autoconf.cpp
-	synch.c
+	synch.cpp
 	systm.cpp
 	sysinit.c
 	taskqueue.c

src/libs/compat/freebsd_network/compat/sys/systm.h

@@ -99,8 +99,6 @@ extern int vsnprintf(char *, size_t, const char *, __va_list)
 int msleep(void *, struct mtx *, int, const char *, int);
 int _pause(const char *, int);
 #define pause(waitMessage, timeout) _pause((waitMessage), (timeout))
-#define tsleep(channel, priority, waitMessage, timeout) \
-	msleep((channel), NULL, (priority), (waitMessage), (timeout))
 #define msleep_spin(chan, mtx, wmesg, timo) \
 	msleep(chan, mtx, PZERO, wmesg, timo)
 #define mtx_sleep msleep

src/libs/compat/freebsd_network/condvar.c

@@ -1,42 +0,0 @@
-/*
- * Copyright 2009 Colin Günther, coling@gmx.de.
- * All rights reserved. Distributed under the terms of the MIT License.
- */
-
-
-#include <compat/sys/mutex.h>
-#include <compat/sys/condvar.h>
-
-#include "Condvar.h"
-
-
-void cv_init(struct cv* variable, const char* description)
-{
-	conditionInit(variable, description);
-}
-
-
-void cv_signal(struct cv* variable)
-{
-	conditionNotifyOne(variable);
-}
-
-
-int cv_timedwait(struct cv* variable, struct mtx* mutex, int timeout)
-{
-	int status;
-
-	mtx_unlock(mutex);
-	status = conditionTimedWait(variable, timeout);
-	mtx_lock(mutex);
-
-	return status;
-}
-
-
-void cv_wait(struct cv* variable, struct mtx* mutex)
-{
-	mtx_unlock(mutex);
-	conditionWait(variable);
-	mtx_lock(mutex);
-}

src/libs/compat/freebsd_network/condvar.cpp

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2022, Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT license.
+ */
+
+#include <compat/sys/mutex.h>
+#include <compat/sys/condvar.h>
+#include <compat/sys/kernel.h>
+
+
+void
+cv_init(struct cv* variable, const char* description)
+{
+	variable->condition.Init(NULL, description);
+}
+
+
+void
+cv_signal(struct cv* variable)
+{
+	variable->condition.NotifyOne();
+}
+
+
+int
+cv_timedwait(struct cv* variable, struct mtx* mutex, int timeout)
+{
+	int status;
+
+	const uint32 flags = timeout ? B_RELATIVE_TIMEOUT : 0;
+	const bigtime_t bigtimeout = TICKS_2_USEC(timeout);
+
+	if (mutex->type == MTX_RECURSE) {
+		// Special case: let the ConditionVariable handle switching recursive locks.
+		status = variable->condition.Wait(&mutex->u.recursive,
+			flags, bigtimeout);
+		return status;
+	}
+
+	ConditionVariableEntry entry;
+	variable->condition.Add(&entry);
+
+	mtx_unlock(mutex);
+
+	status = entry.Wait(flags, bigtimeout);
+
+	mtx_lock(mutex);
+	return status;
+}
+
+
+void
+cv_wait(struct cv* variable, struct mtx* mutex)
+{
+	cv_timedwait(variable, mutex, 0);
+}

src/libs/compat/freebsd_network/synch.c

@@ -1,51 +0,0 @@
-/*
- * Copyright 2009 Colin Günther, coling@gmx.de
- * All rights reserved. Distributed under the terms of the MIT License.
- */
-
-
-#include <compat/sys/systm.h>
-#include <compat/sys/kernel.h>
-#include <compat/sys/mutex.h>
-#include <compat/sys/condvar.h>
-
-#include "Condvar.h"
-
-
-int
-msleep(void* identifier, struct mtx* mutex, int priority,
-	const char* description, int timeout)
-{
-	int status;
-	struct cv sleep;
-
-	conditionPublish(&sleep, identifier, description);
-
-	// FreeBSD's msleep() does not allow the mutex to be NULL, but we
-	// do, as we implement some other functions like tsleep() with it.
-	if (mutex != NULL)
-		mtx_unlock(mutex);
-
-	status = publishedConditionTimedWait(identifier, timeout);
-
-	if (mutex != NULL)
-		mtx_lock(mutex);
-
-	conditionUnpublish(&sleep);
-
-	return status;
-}
-
-
-void
-wakeup(void* identifier)
-{
-	publishedConditionNotifyAll(identifier);
-}
-
-
-void
-wakeup_one(void* identifier)
-{
-	publishedConditionNotifyOne(identifier);
-}

src/libs/compat/freebsd_network/synch.cpp

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2022, Haiku, Inc. All rights reserved.
+ * Distributed under the terms of the MIT license.
+ */
+
+#include <compat/sys/systm.h>
+#include <compat/sys/kernel.h>
+#include <compat/sys/mutex.h>
+#include <compat/sys/condvar.h>
+
+
+int
+msleep(void* identifier, struct mtx* mutex, int priority,
+	const char* description, int timeout)
+{
+	struct cv channel;
+	channel.condition.Publish(identifier, description);
+
+	int status = cv_timedwait(&channel, mutex, timeout);
+
+	channel.condition.Unpublish();
+	return status;
+}
+
+
+void
+wakeup(void* identifier)
+{
+	ConditionVariable::NotifyAll(identifier, B_OK);
+}
+
+
+void
+wakeup_one(void* identifier)
+{
+	ConditionVariable::NotifyOne(identifier, B_OK);
+}