Home | History | Annotate | Line # | Download | only in linux
ww_mutex.h revision 1.8.2.1 
      1 /*	$NetBSD: ww_mutex.h,v 1.8.2.1 2015/04/06 15:18:17 skrll 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 struct ww_class {
     41 	volatile uint64_t	wwc_ticket;
     42 };
     43 
     44 #define	DEFINE_WW_CLASS(CLASS)						      \
     45 	struct ww_class CLASS = {					      \
     46 		.wwc_ticket = 0,					      \
     47 	}
     48 
     49 struct ww_acquire_ctx {
     50 	struct ww_class	*wwx_class __diagused;
     51 	struct lwp	*wwx_owner __diagused;
     52 	uint64_t	wwx_ticket;
     53 	unsigned	wwx_acquired;
     54 	bool		wwx_acquire_done;
     55 	struct rb_node	wwx_rb_node;
     56 };
     57 
     58 struct ww_mutex {
     59 	kmutex_t		wwm_lock;
     60 	enum ww_mutex_state {
     61 		WW_UNLOCKED,	/* nobody owns it */
     62 		WW_OWNED,	/* owned by a lwp without a context */
     63 		WW_CTX,		/* owned by a context */
     64 		WW_WANTOWN,	/* owned by ctx, waiters w/o ctx waiting */
     65 	}			wwm_state;
     66 	union {
     67 		struct lwp		*owner;
     68 		struct ww_acquire_ctx	*ctx;
     69 	}			wwm_u;
     70 	struct ww_class		*wwm_class;
     71 	struct rb_tree		wwm_waiters;
     72 	kcondvar_t		wwm_cv;
     73 };
     74 
     75 /* XXX Make the nm output a little more greppable...  */
     76 #define	ww_acquire_done		linux_ww_acquire_done
     77 #define	ww_acquire_fini		linux_ww_acquire_fini
     78 #define	ww_acquire_init		linux_ww_acquire_init
     79 #define	ww_mutex_destroy	linux_ww_mutex_destroy
     80 #define	ww_mutex_init		linux_ww_mutex_init
     81 #define	ww_mutex_is_locked	linux_ww_mutex_is_locked
     82 #define	ww_mutex_lock		linux_ww_mutex_lock
     83 #define	ww_mutex_lock_interruptible linux_ww_mutex_lock_interruptible
     84 #define	ww_mutex_lock_slow	linux_ww_mutex_lock_slow
     85 #define	ww_mutex_lock_slow_interruptible linux_ww_mutex_lock_slow_interruptible
     86 #define	ww_mutex_trylock	linux_ww_mutex_trylock
     87 #define	ww_mutex_unlock		linux_ww_mutex_unlock
     88 
     89 void	ww_acquire_init(struct ww_acquire_ctx *, struct ww_class *);
     90 void	ww_acquire_done(struct ww_acquire_ctx *);
     91 void	ww_acquire_fini(struct ww_acquire_ctx *);
     92 
     93 void	ww_mutex_init(struct ww_mutex *, struct ww_class *);
     94 void	ww_mutex_destroy(struct ww_mutex *);
     95 
     96 /*
     97  * WARNING: ww_mutex_is_locked returns true if it is locked by ANYONE.
     98  * Does NOT mean `Do I hold this lock?' (answering which really
     99  * requires an acquire context).
    100  */
    101 bool	ww_mutex_is_locked(struct ww_mutex *);
    102 
    103 int	ww_mutex_lock(struct ww_mutex *, struct ww_acquire_ctx *);
    104 int	ww_mutex_lock_interruptible(struct ww_mutex *,
    105 	    struct ww_acquire_ctx *);
    106 void	ww_mutex_lock_slow(struct ww_mutex *, struct ww_acquire_ctx *);
    107 int	ww_mutex_lock_slow_interruptible(struct ww_mutex *,
    108 	    struct ww_acquire_ctx *);
    109 int	ww_mutex_trylock(struct ww_mutex *);
    110 void	ww_mutex_unlock(struct ww_mutex *);
    111 
    112 #endif  /* _ASM_WW_MUTEX_H_ */
    113