MFC r307567 (by sbruno): Assert that we're assigning a non-null taskqueue.

ref: https://github.com/NextBSD/NextBSD/commit/535865d02c162e415d7436899cd6db5000a0cc7b

Fix cpu assignment by assuring stride is non-zero, assert that all tasks
have a valid taskqueue.
ref: https://github.com/NextBSD/NextBSD/commit/db398176234fe3ce9f8e8b671f56000f8276feba

Start cpu assignment from zero.
ref: https://github.com/NextBSD/NextBSD/commit/d99d39b6b6c5dfac1eb440c41e36ebf4c897198e

1 files changed, 14 insertions, 3 deletions

diff --git a/sys/kern/subr_gtaskqueue.c b/sys/kern/subr_gtaskqueue.c
index 115d834..b54e4b8 100644
--- a/sys/kern/subr_gtaskqueue.c
+++ b/sys/kern/subr_gtaskqueue.c
@@ -666,6 +666,7 @@ taskqgroup_attach_deferred(struct taskqgroup *qgroup, struct grouptask *gtask)
 
 	LIST_INSERT_HEAD(&qgroup->tqg_queue[qid].tgc_tasks, gtask,
 			 gt_list);
+	MPASS(qgroup->tqg_queue[qid].tgc_taskq != NULL);
 	gtask->gt_taskqueue = qgroup->tqg_queue[qid].tgc_taskq;
 	mtx_unlock(&qgroup->tqg_lock);
 }
@@ -730,6 +731,7 @@ taskqgroup_attach_cpu_deferred(struct taskqgroup *qgroup, struct grouptask *gtas
 	}
 	qgroup->tqg_queue[qid].tgc_cnt++;
 	LIST_INSERT_HEAD(&qgroup->tqg_queue[qid].tgc_tasks, gtask, gt_list);
+	MPASS(qgroup->tqg_queue[qid].tgc_taskq != NULL);
 	gtask->gt_taskqueue = qgroup->tqg_queue[qid].tgc_taskq;
 	mtx_unlock(&qgroup->tqg_lock);
 
@@ -835,10 +837,10 @@ _taskqgroup_adjust(struct taskqgroup *qgroup, int cnt, int stride)
 	 */
 	cpu = old_cpu;
 	for (i = old_cnt; i < cnt; i++) {
-		for (k = 0; k < qgroup->tqg_stride; k++)
-			cpu = CPU_NEXT(cpu);
-
 		taskqgroup_cpu_create(qgroup, i, cpu);
+
+		for (k = 0; k < stride; k++)
+			cpu = CPU_NEXT(cpu);
 	}
 	mtx_lock(&qgroup->tqg_lock);
 	qgroup->tqg_cnt = cnt;
@@ -865,6 +867,15 @@ _taskqgroup_adjust(struct taskqgroup *qgroup, int cnt, int stride)
 			taskqgroup_attach_deferred(qgroup, gtask);
 	}
 
+#ifdef INVARIANTS
+	mtx_lock(&qgroup->tqg_lock);
+	for (i = 0; i < qgroup->tqg_cnt; i++) {
+		MPASS(qgroup->tqg_queue[i].tgc_taskq != NULL);
+		LIST_FOREACH(gtask, &qgroup->tqg_queue[i].tgc_tasks, gt_list)
+			MPASS(gtask->gt_taskqueue != NULL);
+	}
+	mtx_unlock(&qgroup->tqg_lock);
+#endif
 	/*
 	 * If taskq thread count has been reduced.
 	 */