Introduce wakeup_proc() a function to un-SSTOP/SSLEEP a thread.

This moves most of the SCHED_LOCK() related to protecting the sleepqueue
and its states to kern/kern_sync.c

Name suggestion from jsg@, ok kettenis@, visa@

6 files changed, 36 insertions, 49 deletions

diff --git a/sys/dev/pci/drm/drm_linux.c b/sys/dev/pci/drm/drm_linux.c
index ddb8be808e9..851d90d5af6 100644
--- a/sys/dev/pci/drm/drm_linux.c
+++ b/sys/dev/pci/drm/drm_linux.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: drm_linux.c,v 1.55 2020/01/05 13:46:02 visa Exp $	*/
+/*	$OpenBSD: drm_linux.c,v 1.56 2020/01/16 16:35:03 mpi Exp $	*/
 /*
  * Copyright (c) 2013 Jonathan Gray <jsg@openbsd.org>
  * Copyright (c) 2015, 2016 Mark Kettenis <kettenis@openbsd.org>
@@ -115,20 +115,8 @@ schedule_timeout(long timeout)
 int
 wake_up_process(struct proc *p)
 {
-	int s, r = 0;
-
-	SCHED_LOCK(s);
 	atomic_cas_ptr(&sch_proc, p, NULL);
-	if (p->p_wchan) {
-		if (p->p_stat == SSLEEP) {
-			setrunnable(p);
-			r = 1;
-		} else
-			unsleep(p);
-	}
-	SCHED_UNLOCK(s);
-
-	return r;
+	return wakeup_proc(p, NULL);
 }
 
 void
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index cabca171b50..172848428b7 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_sig.c,v 1.241 2020/01/14 08:52:18 mpi Exp $	*/
+/*	$OpenBSD: kern_sig.c,v 1.242 2020/01/16 16:35:03 mpi Exp $	*/
 /*	$NetBSD: kern_sig.c,v 1.54 1996/04/22 01:38:32 christos Exp $	*/
 
 /*
@@ -1109,7 +1109,7 @@ ptsignal(struct proc *p, int signum, enum signal_type type)
 		 * runnable and can look at the signal.  But don't make
 		 * the process runnable, leave it stopped.
 		 */
-		if (p->p_wchan && p->p_flag & P_SINTR)
+		if (p->p_flag & P_SINTR)
 			unsleep(p);
 		goto out;
 
diff --git a/sys/kern/kern_synch.c b/sys/kern/kern_synch.c
index 7d3c86481f3..da5b4e9b34e 100644
--- a/sys/kern/kern_synch.c
+++ b/sys/kern/kern_synch.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_synch.c,v 1.157 2020/01/14 08:52:18 mpi Exp $	*/
+/*	$OpenBSD: kern_synch.c,v 1.158 2020/01/16 16:35:04 mpi Exp $	*/
 /*	$NetBSD: kern_synch.c,v 1.37 1996/04/22 01:38:37 christos Exp $	*/
 
 /*
@@ -469,8 +469,7 @@ sleep_setup_signal(struct sleep_state *sls)
 	 */
 	atomic_setbits_int(&p->p_flag, P_SINTR);
 	if (p->p_p->ps_single != NULL || (sls->sls_sig = CURSIG(p)) != 0) {
-		if (p->p_wchan)
-			unsleep(p);
+		unsleep(p);
 		p->p_stat = SONPROC;
 		sls->sls_do_sleep = 0;
 	} else if (p->p_wchan == 0) {
@@ -505,6 +504,25 @@ sleep_finish_signal(struct sleep_state *sls)
 	return (error);
 }
 
+int
+wakeup_proc(struct proc *p, const volatile void *chan)
+{
+	int s, awakened = 0;
+
+	SCHED_LOCK(s);
+	if (p->p_wchan != NULL &&
+	   ((chan == NULL) || (p->p_wchan == chan))) {
+		awakened = 1;
+		if (p->p_stat == SSLEEP)
+			setrunnable(p);
+		else
+			unsleep(p);
+	}
+	SCHED_UNLOCK(s);
+
+	return awakened;
+}
+
 /*
  * Implement timeout for tsleep.
  * If process hasn't been awakened (wchan non-zero),
@@ -518,13 +536,8 @@ endtsleep(void *arg)
 	int s;
 
 	SCHED_LOCK(s);
-	if (p->p_wchan) {
-		if (p->p_stat == SSLEEP)
-			setrunnable(p);
-		else
-			unsleep(p);
+	if (wakeup_proc(p, NULL))
 		atomic_setbits_int(&p->p_flag, P_TIMEOUT);
-	}
 	SCHED_UNLOCK(s);
 }
 
@@ -536,7 +549,7 @@ unsleep(struct proc *p)
 {
 	SCHED_ASSERT_LOCKED();
 
-	if (p->p_wchan) {
+	if (p->p_wchan != NULL) {
 		TAILQ_REMOVE(&slpque[LOOKUP(p->p_wchan)], p, p_runq);
 		p->p_wchan = NULL;
 	}
@@ -570,13 +583,8 @@ wakeup_n(const volatile void *ident, int n)
 		if (p->p_stat != SSLEEP && p->p_stat != SSTOP)
 			panic("wakeup: p_stat is %d", (int)p->p_stat);
 #endif
-		if (p->p_wchan == ident) {
+		if (wakeup_proc(p, ident))
 			--n;
-			p->p_wchan = 0;
-			TAILQ_REMOVE(qp, p, p_runq);
-			if (p->p_stat == SSLEEP)
-				setrunnable(p);
-		}
 	}
 	SCHED_UNLOCK(s);
 }
diff --git a/sys/kern/sys_generic.c b/sys/kern/sys_generic.c
index b2870249c99..dc050095a33 100644
--- a/sys/kern/sys_generic.c
+++ b/sys/kern/sys_generic.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: sys_generic.c,v 1.127 2020/01/08 16:27:41 visa Exp $	*/
+/*	$OpenBSD: sys_generic.c,v 1.128 2020/01/16 16:35:04 mpi Exp $	*/
 /*	$NetBSD: sys_generic.c,v 1.24 1996/03/29 00:25:32 cgd Exp $	*/
 
 /*
@@ -767,7 +767,6 @@ void
 selwakeup(struct selinfo *sip)
 {
 	struct proc *p;
-	int s;
 
 	KNOTE(&sip->si_note, NOTE_SUBMIT);
 	if (sip->si_seltid == 0)
@@ -780,15 +779,10 @@ selwakeup(struct selinfo *sip)
 	p = tfind(sip->si_seltid);
 	sip->si_seltid = 0;
 	if (p != NULL) {
-		SCHED_LOCK(s);
-		if (p->p_wchan == (caddr_t)&selwait) {
-			if (p->p_stat == SSLEEP)
-				setrunnable(p);
-			else
-				unsleep(p);
+		if (wakeup_proc(p, &selwait)) {
+			/* nothing else to do */
 		} else if (p->p_flag & P_SELECT)
 			atomic_clearbits_int(&p->p_flag, P_SELECT);
-		SCHED_UNLOCK(s);
 	}
 }
 
diff --git a/sys/kern/vfs_sync.c b/sys/kern/vfs_sync.c
index 14fc49787dc..d871f111836 100644
--- a/sys/kern/vfs_sync.c
+++ b/sys/kern/vfs_sync.c
@@ -1,4 +1,4 @@
-/*       $OpenBSD: vfs_sync.c,v 1.61 2019/12/08 12:29:42 mpi Exp $  */
+/*       $OpenBSD: vfs_sync.c,v 1.62 2020/01/16 16:35:04 mpi Exp $  */
 
 /*
  *  Portions of this code are:
@@ -241,12 +241,8 @@ syncer_thread(void *arg)
 int
 speedup_syncer(void)
 {
-	int s;
-
-	SCHED_LOCK(s);
-	if (syncerproc && syncerproc->p_wchan == &lbolt)
-		setrunnable(syncerproc);
-	SCHED_UNLOCK(s);
+	if (syncerproc)
+		wakeup_proc(syncerproc, &lbolt);
 	if (rushjob < syncdelay / 2) {
 		rushjob += 1;
 		stat_rush_requests += 1;
diff --git a/sys/sys/proc.h b/sys/sys/proc.h
index bb39ab71bae..c463e736f8a 100644
--- a/sys/sys/proc.h
+++ b/sys/sys/proc.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: proc.h,v 1.284 2020/01/06 10:25:10 visa Exp $	*/
+/*	$OpenBSD: proc.h,v 1.285 2020/01/16 16:35:04 mpi Exp $	*/
 /*	$NetBSD: proc.h,v 1.44 1996/04/22 01:23:21 christos Exp $	*/
 
 /*-
@@ -564,6 +564,7 @@ void	procinit(void);
 void	setpriority(struct proc *, uint32_t, uint8_t);
 void	setrunnable(struct proc *);
 void	endtsleep(void *);
+int	wakeup_proc(struct proc *, const volatile void *);
 void	unsleep(struct proc *);
 void	reaper(void *);
 void	exit1(struct proc *, int, int, int);