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Date:      Fri, 2 Feb 2018 18:38:29 +0000 (UTC)
From:      Alexander Motin <mav@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org
Subject:   svn commit: r328805 - in stable/11/sys: kern sys
Message-ID:  <201802021838.w12IcT5P027095@repo.freebsd.org>
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Author: mav
Date: Fri Feb  2 18:38:29 2018
New Revision: 328805
URL: https://svnweb.freebsd.org/changeset/base/328805

Log:
  MFC r312293,312305,312434,312698,312759,312760,312814,312815,322672:
  Synchronize gtaskqueue vs SMP initialization order with head.
  
  This should fix panics on boot, caused by recent Linux KPI merges.

Modified:
  stable/11/sys/kern/subr_gtaskqueue.c
  stable/11/sys/sys/gtaskqueue.h
Directory Properties:
  stable/11/   (props changed)

Modified: stable/11/sys/kern/subr_gtaskqueue.c
==============================================================================
--- stable/11/sys/kern/subr_gtaskqueue.c	Fri Feb  2 18:12:09 2018	(r328804)
+++ stable/11/sys/kern/subr_gtaskqueue.c	Fri Feb  2 18:38:29 2018	(r328805)
@@ -633,6 +633,31 @@ taskqgroup_find(struct taskqgroup *qgroup, void *uniq)
 	return (idx);
 }
 
+/*
+ * smp_started is unusable since it is not set for UP kernels or even for
+ * SMP kernels when there is 1 CPU.  This is usually handled by adding a
+ * (mp_ncpus == 1) test, but that would be broken here since we need to
+ * to synchronize with the SI_SUB_SMP ordering.  Even in the pure SMP case
+ * smp_started only gives a fuzzy ordering relative to SI_SUB_SMP.
+ *
+ * So maintain our own flag.  It must be set after all CPUs are started
+ * and before SI_SUB_SMP:SI_ORDER_ANY so that the SYSINIT for delayed
+ * adjustment is properly delayed.  SI_ORDER_FOURTH is clearly before
+ * SI_ORDER_ANY and unclearly after the CPUs are started.  It would be
+ * simpler for adjustment to pass a flag indicating if it is delayed.
+ */ 
+
+static int tqg_smp_started;
+
+static void
+tqg_record_smp_started(void *arg)
+{
+	tqg_smp_started = 1;
+}
+
+SYSINIT(tqg_record_smp_started, SI_SUB_SMP, SI_ORDER_FOURTH,
+	tqg_record_smp_started, NULL);
+
 void
 taskqgroup_attach(struct taskqgroup *qgroup, struct grouptask *gtask,
     void *uniq, int irq, char *name)
@@ -649,7 +674,7 @@ taskqgroup_attach(struct taskqgroup *qgroup, struct gr
 	qgroup->tqg_queue[qid].tgc_cnt++;
 	LIST_INSERT_HEAD(&qgroup->tqg_queue[qid].tgc_tasks, gtask, gt_list);
 	gtask->gt_taskqueue = qgroup->tqg_queue[qid].tgc_taskq;
-	if (irq != -1 && (smp_started || mp_ncpus == 1)) {
+	if (irq != -1 && tqg_smp_started) {
 		gtask->gt_cpu = qgroup->tqg_queue[qid].tgc_cpu;
 		CPU_ZERO(&mask);
 		CPU_SET(qgroup->tqg_queue[qid].tgc_cpu, &mask);
@@ -699,7 +724,7 @@ taskqgroup_attach_cpu(struct taskqgroup *qgroup, struc
 	gtask->gt_irq = irq;
 	gtask->gt_cpu = cpu;
 	mtx_lock(&qgroup->tqg_lock);
-	if (smp_started || mp_ncpus == 1) {
+	if (tqg_smp_started) {
 		for (i = 0; i < qgroup->tqg_cnt; i++)
 			if (qgroup->tqg_queue[i].tgc_cpu == cpu) {
 				qid = i;
@@ -719,7 +744,7 @@ taskqgroup_attach_cpu(struct taskqgroup *qgroup, struc
 
 	CPU_ZERO(&mask);
 	CPU_SET(cpu, &mask);
-	if (irq != -1 && (smp_started || mp_ncpus == 1))
+	if (irq != -1 && tqg_smp_started)
 		intr_setaffinity(irq, &mask);
 	return (0);
 }
@@ -733,7 +758,7 @@ taskqgroup_attach_cpu_deferred(struct taskqgroup *qgro
 	qid = -1;
 	irq = gtask->gt_irq;
 	cpu = gtask->gt_cpu;
-	MPASS(smp_started || mp_ncpus == 1);
+	MPASS(tqg_smp_started);
 	mtx_lock(&qgroup->tqg_lock);
 	for (i = 0; i < qgroup->tqg_cnt; i++)
 		if (qgroup->tqg_queue[i].tgc_cpu == cpu) {
@@ -826,9 +851,10 @@ _taskqgroup_adjust(struct taskqgroup *qgroup, int cnt,
 
 	mtx_assert(&qgroup->tqg_lock, MA_OWNED);
 
-	if (cnt < 1 || cnt * stride > mp_ncpus || (!smp_started && (mp_ncpus != 1))) {
-		printf("taskqgroup_adjust failed cnt: %d stride: %d mp_ncpus: %d smp_started: %d\n",
-			   cnt, stride, mp_ncpus, smp_started);
+	if (cnt < 1 || cnt * stride > mp_ncpus || !tqg_smp_started) {
+		printf("%s: failed cnt: %d stride: %d "
+		    "mp_ncpus: %d tqg_smp_started: %d\n",
+		    __func__, cnt, stride, mp_ncpus, tqg_smp_started);
 		return (EINVAL);
 	}
 	if (qgroup->tqg_adjusting) {

Modified: stable/11/sys/sys/gtaskqueue.h
==============================================================================
--- stable/11/sys/sys/gtaskqueue.h	Fri Feb  2 18:12:09 2018	(r328804)
+++ stable/11/sys/sys/gtaskqueue.h	Fri Feb  2 18:38:29 2018	(r328805)
@@ -80,8 +80,6 @@ int	taskqgroup_adjust(struct taskqgroup *qgroup, int c
 #define TASKQGROUP_DECLARE(name)			\
 extern struct taskqgroup *qgroup_##name
 
-
-#ifdef EARLY_AP_STARTUP
 #define TASKQGROUP_DEFINE(name, cnt, stride)				\
 									\
 struct taskqgroup *qgroup_##name;					\
@@ -90,23 +88,9 @@ static void								\
 taskqgroup_define_##name(void *arg)					\
 {									\
 	qgroup_##name = taskqgroup_create(#name);			\
-	taskqgroup_adjust(qgroup_##name, (cnt), (stride));		\
 }									\
 									\
-SYSINIT(taskqgroup_##name, SI_SUB_INIT_IF, SI_ORDER_FIRST,		\
-	taskqgroup_define_##name, NULL)
-#else
-#define TASKQGROUP_DEFINE(name, cnt, stride)				\
-									\
-struct taskqgroup *qgroup_##name;					\
-									\
-static void								\
-taskqgroup_define_##name(void *arg)					\
-{									\
-	qgroup_##name = taskqgroup_create(#name);			\
-}									\
-									\
-SYSINIT(taskqgroup_##name, SI_SUB_INIT_IF, SI_ORDER_FIRST,		\
+SYSINIT(taskqgroup_##name, SI_SUB_TASKQ, SI_ORDER_FIRST,		\
 	taskqgroup_define_##name, NULL);				\
 									\
 static void								\
@@ -116,10 +100,8 @@ taskqgroup_adjust_##name(void *arg)					\
 }									\
 									\
 SYSINIT(taskqgroup_adj_##name, SI_SUB_SMP, SI_ORDER_ANY,		\
-	taskqgroup_adjust_##name, NULL);				\
-									\
-struct __hack
-#endif
+	taskqgroup_adjust_##name, NULL)
+
 TASKQGROUP_DECLARE(net);
 TASKQGROUP_DECLARE(softirq);

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