Revert series of callout guard commits (#423)

* Revert "Fix callout stop deadlock"

This reverts commit 21943f41104efcd40e801d6542b110b5440b498d.

* Revert "Fix for missing timer wait wakeups"

This reverts commit faf6330b91d7e9768aa10f3f22484885a83e0f02.

* Revert "Fix for rescheduling a timer that is currently in progress."

This reverts commit d225e88dcafbbfc865c67589353c6a9ae3ce9bc8.

* Revert "Pull in missing guard for the currently executing callout (v2)"

This reverts commit 164ca603a26ebb870418fa5709f09bab9b61a3ab.

* Revert "Pull in missing guard for the currently executing callout"

This reverts commit a7c290275a0f8a164c132396b34f46e295c193f7.

5 files changed, 1 insertions, 146 deletions

diff --git a/usrsctplib/netinet/sctp_callout.c b/usrsctplib/netinet/sctp_callout.c
index a08d6408..c6cffc78 100755
--- a/usrsctplib/netinet/sctp_callout.c
+++ b/usrsctplib/netinet/sctp_callout.c
@@ -77,27 +77,8 @@ uint32_t sctp_get_tick_count(void) {
  * SCTP_TIMERQ_LOCK protects:
  * - SCTP_BASE_INFO(callqueue)
  * - sctp_os_timer_next: next timer to check
- * - sctp_os_timer_current: current callout callback in progress
- * - sctp_os_timer_current_tid: current callout thread id in progress
- * - sctp_os_timer_waiting: some thread is waiting for callout to complete
- * - sctp_os_timer_wait_ctr: incremented every time a thread wants to wait
- *                           for a callout to complete.
  */
 static sctp_os_timer_t *sctp_os_timer_next = NULL;
-static sctp_os_timer_t *sctp_os_timer_current = NULL;
-static int sctp_os_timer_waiting = 0;
-static int sctp_os_timer_wait_ctr = 0;
-static userland_thread_id_t sctp_os_timer_current_tid;
-
-/*
- * SCTP_TIMERWAIT_LOCK (sctp_os_timerwait_mtx) protects:
- * - sctp_os_timer_wait_cond: waiting for callout to complete
- * - sctp_os_timer_done_ctr: value of "wait_ctr" after triggering "waiting"
- */
-userland_mutex_t sctp_os_timerwait_mtx;
-static userland_cond_t sctp_os_timer_wait_cond;
-static int sctp_os_timer_done_ctr = 0;
-
 
 void
 sctp_os_timer_init(sctp_os_timer_t *c)
@@ -115,21 +96,6 @@ sctp_os_timer_start(sctp_os_timer_t *c, uint32_t to_ticks, void (*ftn) (void *),
 
 	SCTP_TIMERQ_LOCK();
 	/* check to see if we're rescheduling a timer */
-	if (c == sctp_os_timer_current) {
-		/*
-		 * We're being asked to reschedule a callout which is
-		 * currently in progress.
-		 */
-		if (sctp_os_timer_waiting) {
-			/*
-			 * This callout is already being stopped.
-			 * callout.  Don't reschedule.
-			 */
-			SCTP_TIMERQ_UNLOCK();
-			return;
-		}
-	}
-
 	if (c->c_flags & SCTP_CALLOUT_PENDING) {
 		if (c == sctp_os_timer_next) {
 			sctp_os_timer_next = TAILQ_NEXT(c, tqe);
@@ -161,51 +127,13 @@ sctp_os_timer_start(sctp_os_timer_t *c, uint32_t to_ticks, void (*ftn) (void *),
 int
 sctp_os_timer_stop(sctp_os_timer_t *c)
 {
-	int wakeup_cookie;
-
 	SCTP_TIMERQ_LOCK();
 	/*
 	 * Don't attempt to delete a callout that's not on the queue.
 	 */
 	if (!(c->c_flags & SCTP_CALLOUT_PENDING)) {
 		c->c_flags &= ~SCTP_CALLOUT_ACTIVE;
-		if (sctp_os_timer_current != c) {
-			SCTP_TIMERQ_UNLOCK();
-			return (0);
-		} else {
-			/*
-			 * Deleting the callout from the currently running
-			 * callout from the same thread, so just return
-			 */
-			userland_thread_id_t tid;
-			sctp_userspace_thread_id(&tid);
-			if (sctp_userspace_thread_equal(tid,
-						sctp_os_timer_current_tid)) {
-				SCTP_TIMERQ_UNLOCK();
-				return (0);
-			}
-
-			/* need to wait until the callout is finished */
-			sctp_os_timer_waiting = 1;
-			wakeup_cookie = ++sctp_os_timer_wait_ctr;
-			SCTP_TIMERQ_UNLOCK();
-			SCTP_TIMERWAIT_LOCK();
-			/*
-			 * wait only if sctp_handle_tick didn't do a wakeup
-			 * in between the lock dance
-			 */
-			if (wakeup_cookie - sctp_os_timer_done_ctr > 0) {
-#if defined (__Userspace_os_Windows)
-				SleepConditionVariableCS(&sctp_os_timer_wait_cond,
-							 &sctp_os_timerwait_mtx,
-							 INFINITE);
-#else
-				pthread_cond_wait(&sctp_os_timer_wait_cond,
-						  &sctp_os_timerwait_mtx);
-#endif
-			}
-			SCTP_TIMERWAIT_UNLOCK();
-		}
+		SCTP_TIMERQ_UNLOCK();
 		return (0);
 	}
 	c->c_flags &= ~(SCTP_CALLOUT_ACTIVE | SCTP_CALLOUT_PENDING);
@@ -223,7 +151,6 @@ sctp_handle_tick(uint32_t elapsed_ticks)
 	sctp_os_timer_t *c;
 	void (*c_func)(void *);
 	void *c_arg;
-	int wakeup_cookie;
 
 	SCTP_TIMERQ_LOCK();
 	/* update our tick count */
@@ -236,26 +163,9 @@ sctp_handle_tick(uint32_t elapsed_ticks)
 			c_func = c->c_func;
 			c_arg = c->c_arg;
 			c->c_flags &= ~SCTP_CALLOUT_PENDING;
-			sctp_os_timer_current = c;
-			sctp_userspace_thread_id(&sctp_os_timer_current_tid);
 			SCTP_TIMERQ_UNLOCK();
 			c_func(c_arg);
 			SCTP_TIMERQ_LOCK();
-			sctp_os_timer_current = NULL;
-			if (sctp_os_timer_waiting) {
-				wakeup_cookie = sctp_os_timer_wait_ctr;
-				SCTP_TIMERQ_UNLOCK();
-				SCTP_TIMERWAIT_LOCK();
-#if defined (__Userspace_os_Windows)
-				WakeAllConditionVariable(&sctp_os_timer_wait_cond);
-#else
-				pthread_cond_broadcast(&sctp_os_timer_wait_cond);
-#endif
-				sctp_os_timer_done_ctr = wakeup_cookie;
-				SCTP_TIMERWAIT_UNLOCK();
-				SCTP_TIMERQ_LOCK();
-				sctp_os_timer_waiting = 0;
-			}
 			c = sctp_os_timer_next;
 		} else {
 			c = TAILQ_NEXT(c, tqe);
@@ -310,14 +220,6 @@ sctp_start_timer(void)
 	 */
 	int rc;
 
-#if defined(__Userspace_os_Windows)
-	InitializeConditionVariable(&sctp_os_timer_wait_cond);
-#else
-	rc = pthread_cond_init(&sctp_os_timer_wait_cond, NULL);
-	if (rc)
-		SCTP_PRINTF("ERROR; return code from pthread_cond_init is %d\n", rc);
-#endif
-
 	rc = sctp_userspace_thread_create(&SCTP_BASE_VAR(timer_thread), user_sctp_timer_iterate);
 	if (rc) {
 		SCTP_PRINTF("ERROR; return code from sctp_thread_create() is %d\n", rc);
diff --git a/usrsctplib/netinet/sctp_callout.h b/usrsctplib/netinet/sctp_callout.h
index 0f4dc6b4..13279da0 100755
--- a/usrsctplib/netinet/sctp_callout.h
+++ b/usrsctplib/netinet/sctp_callout.h
@@ -52,35 +52,22 @@ __FBSDID("$FreeBSD$");
 
 #define SCTP_TICKS_PER_FASTTIMO 20	/* called about every 20ms */
 
-extern userland_mutex_t sctp_os_timerwait_mtx;
-
 #if defined(__Userspace__)
 #if defined(__Userspace_os_Windows)
 #define SCTP_TIMERQ_LOCK()          EnterCriticalSection(&SCTP_BASE_VAR(timer_mtx))
 #define SCTP_TIMERQ_UNLOCK()        LeaveCriticalSection(&SCTP_BASE_VAR(timer_mtx))
 #define SCTP_TIMERQ_LOCK_INIT()     InitializeCriticalSection(&SCTP_BASE_VAR(timer_mtx))
 #define SCTP_TIMERQ_LOCK_DESTROY()  DeleteCriticalSection(&SCTP_BASE_VAR(timer_mtx))
-
-#define SCTP_TIMERWAIT_LOCK()          EnterCriticalSection(&sctp_os_timerwait_mtx)
-#define SCTP_TIMERWAIT_UNLOCK()        LeaveCriticalSection(&sctp_os_timerwait_mtx)
-#define SCTP_TIMERWAIT_LOCK_INIT()     InitializeCriticalSection(&sctp_os_timerwait_mtx)
-#define SCTP_TIMERWAIT_LOCK_DESTROY()  DeleteCriticalSection(&sctp_os_timerwait_mtx)
 #else
 #ifdef INVARIANTS
 #define SCTP_TIMERQ_LOCK()          KASSERT(pthread_mutex_lock(&SCTP_BASE_VAR(timer_mtx)) == 0, ("%s: timer_mtx already locked", __func__))
 #define SCTP_TIMERQ_UNLOCK()        KASSERT(pthread_mutex_unlock(&SCTP_BASE_VAR(timer_mtx)) == 0, ("%s: timer_mtx not locked", __func__))
-#define SCTP_TIMERWAIT_LOCK()       KASSERT(pthread_mutex_lock(&sctp_os_timerwait_mtx) == 0, ("%s: sctp_os_timerwait_mtx already locked", __func__))
-#define SCTP_TIMERWAIT_UNLOCK()	    KASSERT(pthread_mutex_unlock(&sctp_os_timerwait_mtx) == 0, ("%s: sctp_os_timerwait_mtx not locked", __func__))
 #else
 #define SCTP_TIMERQ_LOCK()          (void)pthread_mutex_lock(&SCTP_BASE_VAR(timer_mtx))
 #define SCTP_TIMERQ_UNLOCK()        (void)pthread_mutex_unlock(&SCTP_BASE_VAR(timer_mtx))
-#define SCTP_TIMERWAIT_LOCK()       (void)pthread_mutex_lock(&sctp_os_timerwait_mtx)
-#define SCTP_TIMERWAIT_UNLOCK()     (void)pthread_mutex_unlock(&sctp_os_timerwait_mtx)
 #endif
 #define SCTP_TIMERQ_LOCK_INIT()     (void)pthread_mutex_init(&SCTP_BASE_VAR(timer_mtx), &SCTP_BASE_VAR(mtx_attr))
 #define SCTP_TIMERQ_LOCK_DESTROY()  (void)pthread_mutex_destroy(&SCTP_BASE_VAR(timer_mtx))
-#define SCTP_TIMERWAIT_LOCK_INIT()     (void)pthread_mutex_init(&sctp_os_timerwait_mtx, &SCTP_BASE_VAR(mtx_attr))
-#define SCTP_TIMERWAIT_LOCK_DESTROY()  (void)pthread_mutex_destroy(&sctp_os_timerwait_mtx)
 #endif
 #endif
 
diff --git a/usrsctplib/netinet/sctp_os_userspace.h b/usrsctplib/netinet/sctp_os_userspace.h
index 9bc190d3..f09cb8da 100755
--- a/usrsctplib/netinet/sctp_os_userspace.h
+++ b/usrsctplib/netinet/sctp_os_userspace.h
@@ -76,7 +76,6 @@ void WakeAllXPConditionVariable(userland_cond_t *);
 typedef CONDITION_VARIABLE userland_cond_t;
 #endif
 typedef HANDLE userland_thread_t;
-typedef DWORD userland_thread_id_t;
 #define ADDRESS_FAMILY	unsigned __int8
 #define IPVERSION  4
 #define MAXTTL     255
@@ -284,7 +283,6 @@ typedef char* caddr_t;
 typedef pthread_mutex_t userland_mutex_t;
 typedef pthread_cond_t userland_cond_t;
 typedef pthread_t userland_thread_t;
-typedef pthread_t userland_thread_id_t;
 #endif
 
 #if defined(__Userspace_os_Windows) || defined(__Userspace_os_NaCl)
@@ -1037,9 +1035,6 @@ sctp_userspace_thread_create(userland_thread_t *thread, start_routine_t start_ro
 void
 sctp_userspace_set_threadname(const char *name);
 
-int sctp_userspace_thread_id(userland_thread_id_t *thread);
-int sctp_userspace_thread_equal(userland_thread_id_t t1, userland_thread_id_t t2);
-
 /*
  * SCTP protocol specific mbuf flags.
  */
diff --git a/usrsctplib/netinet/sctp_pcb.c b/usrsctplib/netinet/sctp_pcb.c
index 2220862f..02779e53 100755
--- a/usrsctplib/netinet/sctp_pcb.c
+++ b/usrsctplib/netinet/sctp_pcb.c
@@ -6845,7 +6845,6 @@ sctp_pcb_init(void)
 #if defined(_SCTP_NEEDS_CALLOUT_) || defined(_USER_SCTP_NEEDS_CALLOUT_)
 	/* allocate the lock for the callout/timer queue */
 	SCTP_TIMERQ_LOCK_INIT();
-	SCTP_TIMERWAIT_LOCK_INIT();
 	TAILQ_INIT(&SCTP_BASE_INFO(callqueue));
 #endif
 #if defined(__Userspace__)
@@ -7041,7 +7040,6 @@ retry:
 	/* free the locks and mutexes */
 #if defined(__APPLE__)
 	SCTP_TIMERQ_LOCK_DESTROY();
-	SCTP_TIMERWAIT_LOCK_DESTROY();
 #endif
 #ifdef SCTP_PACKET_LOGGING
 	SCTP_IP_PKTLOG_DESTROY();
@@ -7068,7 +7066,6 @@ retry:
 #endif
 #if defined(__Userspace__)
 	SCTP_TIMERQ_LOCK_DESTROY();
-	SCTP_TIMERWAIT_LOCK_DESTROY();
 	SCTP_ZONE_DESTROY(zone_mbuf);
 	SCTP_ZONE_DESTROY(zone_clust);
 	SCTP_ZONE_DESTROY(zone_ext_refcnt);
diff --git a/usrsctplib/netinet/sctp_userspace.c b/usrsctplib/netinet/sctp_userspace.c
index 7ff8a2d4..28922b6a 100755
--- a/usrsctplib/netinet/sctp_userspace.c
+++ b/usrsctplib/netinet/sctp_userspace.c
@@ -68,19 +68,6 @@ sctp_userspace_thread_create(userland_thread_t *thread, start_routine_t start_ro
 	return 0;
 }
 
-int
-sctp_userspace_thread_id(userland_thread_id_t *thread)
-{
-	*thread = GetCurrentThreadId();
-	return 0;
-}
-
-int
-sctp_userspace_thread_equal(userland_thread_id_t t1, userland_thread_id_t t2)
-{
-	return (t1 == t2);
-}
-
 #if defined(__MINGW32__)
 #pragma GCC diagnostic pop
 #endif
@@ -91,19 +78,6 @@ sctp_userspace_thread_create(userland_thread_t *thread, start_routine_t start_ro
 {
 	return pthread_create(thread, NULL, start_routine, NULL);
 }
-
-int
-sctp_userspace_thread_id(userland_thread_id_t *thread)
-{
-	*thread = pthread_self();
-	return 0;
-}
-
-int
-sctp_userspace_thread_equal(userland_thread_id_t t1, userland_thread_id_t t2)
-{
-	return pthread_equal(t1, t2);
-}
 #endif
 
 void