From 3b01ae665985d315e329f5277bceefdc5b989064 Mon Sep 17 00:00:00 2001
From: visa <visa@openbsd.org>
Date: Sun, 13 Feb 2022 13:03:02 +0000
Subject: [PATCH] Add helper functions for f_modify and f_process to condense
 code

These new functions, knote_modify() and knote_process(), implement
the logic that is common to most f_modify and f_process instances.

The code is inlined so as to not add yet another call frame on the
already towering stack of kqueue functions. Also, the _fn versions
allow direct calling of an event function when there is only one
filter type to handle.
---
 sys/sys/event.h | 41 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/sys/sys/event.h b/sys/sys/event.h
index 2ec51183892..6aa346183cb 100644
--- a/sys/sys/event.h
+++ b/sys/sys/event.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: event.h,v 1.65 2022/02/13 12:58:46 visa Exp $	*/
+/*	$OpenBSD: event.h,v 1.66 2022/02/13 13:03:02 visa Exp $	*/
 
 /*-
  * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
@@ -316,6 +316,45 @@ extern void	klist_remove(struct klist *, struct knote *);
 extern void	klist_remove_locked(struct klist *, struct knote *);
 extern void	klist_invalidate(struct klist *);
 
+static inline int
+knote_modify_fn(const struct kevent *kev, struct knote *kn,
+    int (*f_event)(struct knote *, long))
+{
+	knote_assign(kev, kn);
+	return ((*f_event)(kn, 0));
+}
+
+static inline int
+knote_modify(const struct kevent *kev, struct knote *kn)
+{
+	return (knote_modify_fn(kev, kn, kn->kn_fop->f_event));
+}
+
+static inline int
+knote_process_fn(struct knote *kn, struct kevent *kev,
+    int (*f_event)(struct knote *, long))
+{
+	int active;
+
+	/*
+	 * If called from kqueue_scan(), skip f_event
+	 * when EV_ONESHOT is set, to preserve old behaviour.
+	 */
+	if (kev != NULL && (kn->kn_flags & EV_ONESHOT))
+		active = 1;
+	else
+		active = (*f_event)(kn, 0);
+	if (active)
+		knote_submit(kn, kev);
+	return (active);
+}
+
+static inline int
+knote_process(struct knote *kn, struct kevent *kev)
+{
+	return (knote_process_fn(kn, kev, kn->kn_fop->f_event));
+}
+
 static inline int
 klist_empty(struct klist *klist)
 {
-- 
2.20.1