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ww_mutex.h revision 1.14 
      1 /*	$NetBSD: ww_mutex.h,v 1.14 2021/12/19 10:38:14 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2014 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 #ifndef _ASM_WW_MUTEX_H_
     33 #define _ASM_WW_MUTEX_H_
     34 
     35 #include <sys/types.h>
     36 #include <sys/condvar.h>
     37 #include <sys/mutex.h>
     38 #include <sys/rbtree.h>
     39 
     40 #include <linux/atomic.h>
     41 #include <linux/mutex.h>
     42 
     43 struct ww_class {
     44 	atomic64_t	wwc_ticket;
     45 };
     46 
     47 #define	DEFINE_WW_CLASS(CLASS)						      \
     48 	struct ww_class CLASS = {					      \
     49 		.wwc_ticket = ATOMIC64_INIT(0),				      \
     50 	}
     51 
     52 struct ww_acquire_ctx {
     53 	struct ww_class	*wwx_class __diagused;
     54 	struct lwp	*wwx_owner __diagused;
     55 	uint64_t	wwx_ticket;
     56 	unsigned	wwx_acquired;
     57 	bool		wwx_acquire_done;
     58 	struct rb_node	wwx_rb_node;
     59 };
     60 
     61 struct ww_mutex {
     62 	enum ww_mutex_state {
     63 		WW_UNLOCKED,	/* nobody owns it */
     64 		WW_OWNED,	/* owned by a lwp without a context */
     65 		WW_CTX,		/* owned by a context */
     66 		WW_WANTOWN,	/* owned by ctx, waiters w/o ctx waiting */
     67 	}			wwm_state;
     68 	union {
     69 		struct lwp		*owner;
     70 		struct ww_acquire_ctx	*ctx;
     71 	}			wwm_u;
     72 	/*
     73 	 * XXX wwm_lock must *not* be first, so that the ww_mutex has a
     74 	 * different address from the kmutex for LOCKDEBUG purposes.
     75 	 */
     76 	kmutex_t		wwm_lock;
     77 	struct ww_class		*wwm_class;
     78 	struct rb_tree		wwm_waiters;
     79 	kcondvar_t		wwm_cv;
     80 #ifdef LOCKDEBUG
     81 	bool			wwm_debug;
     82 #endif
     83 };
     84 
     85 /* XXX Make the nm output a little more greppable...  */
     86 #define	ww_acquire_done		linux_ww_acquire_done
     87 #define	ww_acquire_fini		linux_ww_acquire_fini
     88 #define	ww_acquire_init		linux_ww_acquire_init
     89 #define	ww_mutex_destroy	linux_ww_mutex_destroy
     90 #define	ww_mutex_init		linux_ww_mutex_init
     91 #define	ww_mutex_is_locked	linux_ww_mutex_is_locked
     92 #define	ww_mutex_lock		linux_ww_mutex_lock
     93 #define	ww_mutex_lock_interruptible linux_ww_mutex_lock_interruptible
     94 #define	ww_mutex_lock_slow	linux_ww_mutex_lock_slow
     95 #define	ww_mutex_lock_slow_interruptible linux_ww_mutex_lock_slow_interruptible
     96 #define	ww_mutex_locking_ctx	linux_ww_mutex_locking_ctx
     97 #define	ww_mutex_trylock	linux_ww_mutex_trylock
     98 #define	ww_mutex_unlock		linux_ww_mutex_unlock
     99 
    100 void	ww_acquire_init(struct ww_acquire_ctx *, struct ww_class *);
    101 void	ww_acquire_done(struct ww_acquire_ctx *);
    102 void	ww_acquire_fini(struct ww_acquire_ctx *);
    103 
    104 void	ww_mutex_init(struct ww_mutex *, struct ww_class *);
    105 void	ww_mutex_destroy(struct ww_mutex *);
    106 
    107 /*
    108  * WARNING: ww_mutex_is_locked returns true if it is locked by ANYONE.
    109  * Does NOT mean `Do I hold this lock?' (answering which really
    110  * requires an acquire context).
    111  */
    112 bool	ww_mutex_is_locked(struct ww_mutex *);
    113 
    114 int	ww_mutex_lock(struct ww_mutex *, struct ww_acquire_ctx *);
    115 int	ww_mutex_lock_interruptible(struct ww_mutex *,
    116 	    struct ww_acquire_ctx *);
    117 void	ww_mutex_lock_slow(struct ww_mutex *, struct ww_acquire_ctx *);
    118 int	ww_mutex_lock_slow_interruptible(struct ww_mutex *,
    119 	    struct ww_acquire_ctx *);
    120 int	ww_mutex_trylock(struct ww_mutex *);
    121 void	ww_mutex_unlock(struct ww_mutex *);
    122 
    123 struct ww_acquire_ctx *
    124 	ww_mutex_locking_ctx(struct ww_mutex *);
    125 
    126 #endif  /* _ASM_WW_MUTEX_H_ */
    127