Support TQ_FRONT flag used by taskq_dispatch()

Allow taskq_dispatch() to insert work items at the head of the
queue instead of just the tail by passing the TQ_FRONT flag.

1 files changed, 7 insertions, 1 deletions

diff --git a/module/spl/spl-taskq.c b/module/spl/spl-taskq.c
index 805749a14..fba38021f 100644
--- a/module/spl/spl-taskq.c
+++ b/module/spl/spl-taskq.c
@@ -274,7 +274,13 @@ __taskq_dispatch(taskq_t *tq, task_func_t func, void *arg, uint_t flags)
 		GOTO(out, rc = 0);
 
 	spin_lock(&t->t_lock);
-	list_add_tail(&t->t_list, &tq->tq_pend_list);
+
+	/* Queue to the head instead of the tail */
+	if (flags & TQ_FRONT)
+		list_add(&t->t_list, &tq->tq_pend_list);
+	else
+		list_add_tail(&t->t_list, &tq->tq_pend_list);
+
 	t->t_id = rc = tq->tq_next_id;
 	tq->tq_next_id++;
         t->t_func = func;