Replace selwakeup() with KNOTE() in kqueue event activation.

The deferred activation can now run in an MP-safe task queue.

diff --git a/sys/kern/kern_event.c b/sys/kern/kern_event.c
index 1e10295..fca006a 100644 (file)
--- a/sys/kern/kern_event.c
+++ b/sys/kern/kern_event.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_event.c,v 1.186 2022/03/31 01:41:22 millert Exp $        */
+/*     $OpenBSD: kern_event.c,v 1.187 2022/05/06 13:12:16 visa Exp $   */
 
 /*-
  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
@@ -1591,8 +1591,7 @@ kqueue_terminate(struct proc *p, struct kqueue *kq)
        mtx_leave(&kq->kq_lock);
 
        KASSERT(klist_empty(&kq->kq_sel.si_note));
-       task_del(systq, &kq->kq_task);
-
+       task_del(systqmp, &kq->kq_task);
 }
 
 int
@@ -1615,19 +1614,8 @@ kqueue_task(void *arg)
 {
        struct kqueue *kq = arg;
 
-       /* Kernel lock is needed inside selwakeup(). */
-       KERNEL_ASSERT_LOCKED();
-
        mtx_enter(&kqueue_klist_lock);
-       mtx_enter(&kq->kq_lock);
-       if (kq->kq_state & KQ_SEL) {
-               kq->kq_state &= ~KQ_SEL;
-               mtx_leave(&kq->kq_lock);
-               selwakeup(&kq->kq_sel);
-       } else {
-               mtx_leave(&kq->kq_lock);
-               KNOTE(&kq->kq_sel.si_note, 0);
-       }
+       KNOTE(&kq->kq_sel.si_note, 0);
        mtx_leave(&kqueue_klist_lock);
        KQRELE(kq);
 }
@@ -1641,10 +1629,10 @@ kqueue_wakeup(struct kqueue *kq)
                kq->kq_state &= ~KQ_SLEEP;
                wakeup(kq);
        }
-       if ((kq->kq_state & KQ_SEL) || !klist_empty(&kq->kq_sel.si_note)) {
+       if (!klist_empty(&kq->kq_sel.si_note)) {
                /* Defer activation to avoid recursion. */
                KQREF(kq);
-               if (!task_add(systq, &kq->kq_task))
+               if (!task_add(systqmp, &kq->kq_task))
                        KQRELE(kq);
        }
 }