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      1 /*	$NetBSD: linux_notifier.c,v 1.2 2021/12/19 11:47:08 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2021 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Taylor R. Campbell.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: linux_notifier.c,v 1.2 2021/12/19 11:47:08 riastradh Exp $");
     34 
     35 #include <sys/types.h>
     36 
     37 #include <sys/pserialize.h>
     38 #include <sys/xcall.h>
     39 
     40 #include <linux/notifier.h>
     41 #include <linux/spinlock.h>
     42 
     43 void
     44 ATOMIC_INIT_NOTIFIER_HEAD(struct atomic_notifier_head *H)
     45 {
     46 
     47 	spin_lock_init(&H->anh_lock);
     48 	PSLIST_INIT(&H->anh_list);
     49 }
     50 
     51 void
     52 ATOMIC_CLEANUP_NOTIFIER_HEAD(struct atomic_notifier_head *H)
     53 {
     54 
     55 	PSLIST_DESTROY(&H->anh_list);
     56 	spin_lock_destroy(&H->anh_lock);
     57 }
     58 
     59 void
     60 atomic_notifier_chain_register(struct atomic_notifier_head *H,
     61     struct notifier_block *B)
     62 {
     63 
     64 	spin_lock(&H->anh_lock);
     65 	PSLIST_WRITER_INSERT_HEAD(&H->anh_list, B, nb_entry);
     66 	spin_unlock(&H->anh_lock);
     67 }
     68 
     69 void
     70 atomic_notifier_chain_unregister(struct atomic_notifier_head *H,
     71     struct notifier_block *B)
     72 {
     73 
     74 	spin_lock(&H->anh_lock);
     75 	PSLIST_WRITER_REMOVE(B, nb_entry);
     76 	spin_unlock(&H->anh_lock);
     77 
     78 	xc_barrier(0);
     79 }
     80 
     81 void
     82 atomic_notifier_call_chain(struct atomic_notifier_head *H,
     83     unsigned long arg0, void *arg1)
     84 {
     85 	struct notifier_block *B;
     86 	int s;
     87 
     88 	s = pserialize_read_enter();
     89 	PSLIST_READER_FOREACH(B, &H->anh_list, struct notifier_block, nb_entry)
     90 	{
     91 		if ((*B->notifier_call)(B, arg0, arg1) == NOTIFY_DONE)
     92 			break;
     93 	}
     94 	pserialize_read_exit(s);
     95 }
     96