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diff --git a/kern/bulletin.h b/kern/bulletin.h
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+/*
+ * Copyright (c) 2017-2018 Richard Braun.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Minimalist publish-subscribe mechanism.
+ */
+
+#ifndef KERN_BULLETIN_H
+#define KERN_BULLETIN_H
+
+#include <stdint.h>
+
+#include <kern/macros.h>
+#include <kern/work.h>
+
+/*
+ * Type for bulletin notification functions.
+ *
+ * The value is passed from the publisher unmodified, and can safely be
+ * cast into a pointer. Notification functions run in the context of the
+ * publisher.
+ */
+typedef void (*bulletin_notif_fn_t)(uintptr_t value, void *arg);
+
+#include <kern/bulletin_i.h>
+
+struct bulletin;
+
+/*
+ * Bulletin subscriber.
+ */
+struct bulletin_sub;
+
+void bulletin_init(struct bulletin *bulletin);
+
+/*
+ * Subscribe to a bulletin.
+ *
+ * Once subscribed, the notification function is called with its argument
+ * each time the bulletin is published.
+ */
+void bulletin_subscribe(struct bulletin *bulletin, struct bulletin_sub *sub,
+                        bulletin_notif_fn_t notif_fn, void *arg);
+
+/*
+ * Unsubscribe from a bulletin.
+ *
+ * On return, the subscriber notification function may not be called any more.
+ *
+ * This function synchronizes with RCU.
+ */
+void bulletin_unsubscribe(struct bulletin *bulletin, struct bulletin_sub *sub);
+
+/*
+ * Publish a bulletin.
+ *
+ * All subscribers are notified by calling their notification function, with
+ * the given value passed unmodified.
+ */
+void bulletin_publish(struct bulletin *bulletin, uintptr_t value);
+
+#endif /* KERN_BULLETIN_H */