33fb8a386e
turn it back on. Specifically, the actual changes are now less intrusive in that the _get_spin_lock() and _rel_spin_lock() macros now have their contents changed for UP vs SMP kernels which centralizes the changes. Also, UP kernels do not use _mtx_lock_spin() and no longer include it. The UP versions of the spin lock functions do not use any atomic operations, but simple compares and stores which allow mtx_owned() to still work for spin locks while removing the overhead of atomic operations. Tested on: i386, alpha
453 lines
15 KiB
C
453 lines
15 KiB
C
/*-
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* Copyright (c) 1997 Berkeley Software Design, Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Berkeley Software Design Inc's name may not be used to endorse or
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* promote products derived from this software without specific prior
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* written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY BERKELEY SOFTWARE DESIGN INC ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL BERKELEY SOFTWARE DESIGN INC BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from BSDI $Id: mutex.h,v 2.7.2.35 2000/04/27 03:10:26 cp Exp $
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* $FreeBSD$
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*/
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#ifndef _SYS_MUTEX_H_
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#define _SYS_MUTEX_H_
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#ifndef LOCORE
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#include <sys/queue.h>
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#include <sys/_lock.h>
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#include <sys/_mutex.h>
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#ifdef _KERNEL
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#include <sys/pcpu.h>
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#include <machine/atomic.h>
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#include <machine/cpufunc.h>
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#endif /* _KERNEL_ */
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#endif /* !LOCORE */
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#include <machine/mutex.h>
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#ifdef _KERNEL
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/*
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* Mutex types and options passed to mtx_init(). MTX_QUIET can also be
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* passed in.
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*/
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#define MTX_DEF 0x00000000 /* DEFAULT (sleep) lock */
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#define MTX_SPIN 0x00000001 /* Spin lock (disables interrupts) */
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#define MTX_RECURSE 0x00000004 /* Option: lock allowed to recurse */
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#define MTX_NOWITNESS 0x00000008 /* Don't do any witness checking. */
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#define MTX_DUPOK 0x00000020 /* Don't log a duplicate acquire */
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/*
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* Option flags passed to certain lock/unlock routines, through the use
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* of corresponding mtx_{lock,unlock}_flags() interface macros.
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*/
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#define MTX_QUIET LOP_QUIET /* Don't log a mutex event */
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/*
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* State bits kept in mutex->mtx_lock, for the DEFAULT lock type. None of this,
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* with the exception of MTX_UNOWNED, applies to spin locks.
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*/
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#define MTX_RECURSED 0x00000001 /* lock recursed (for MTX_DEF only) */
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#define MTX_CONTESTED 0x00000002 /* lock contested (for MTX_DEF only) */
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#define MTX_UNOWNED 0x00000004 /* Cookie for free mutex */
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#define MTX_FLAGMASK ~(MTX_RECURSED | MTX_CONTESTED)
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#endif /* _KERNEL */
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#ifndef LOCORE
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/*
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* XXX: Friendly reminder to fix things in MP code that is presently being
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* XXX: worked on.
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*/
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#define mp_fixme(string)
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#ifdef _KERNEL
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/*
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* Prototypes
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*
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* NOTE: Functions prepended with `_' (underscore) are exported to other parts
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* of the kernel via macros, thus allowing us to use the cpp LOCK_FILE
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* and LOCK_LINE. These functions should not be called directly by any
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* code using the API. Their macros cover their functionality.
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*
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* [See below for descriptions]
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*
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*/
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void mtx_init(struct mtx *m, const char *name, const char *type, int opts);
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void mtx_destroy(struct mtx *m);
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void mtx_sysinit(void *arg);
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void mutex_init(void);
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void _mtx_lock_sleep(struct mtx *m, struct thread *td, int opts,
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const char *file, int line);
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void _mtx_unlock_sleep(struct mtx *m, int opts, const char *file, int line);
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#ifdef SMP
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void _mtx_lock_spin(struct mtx *m, struct thread *td, int opts,
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const char *file, int line);
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#endif
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void _mtx_unlock_spin(struct mtx *m, int opts, const char *file, int line);
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int _mtx_trylock(struct mtx *m, int opts, const char *file, int line);
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void _mtx_lock_flags(struct mtx *m, int opts, const char *file, int line);
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void _mtx_unlock_flags(struct mtx *m, int opts, const char *file, int line);
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void _mtx_lock_spin_flags(struct mtx *m, int opts, const char *file,
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int line);
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void _mtx_unlock_spin_flags(struct mtx *m, int opts, const char *file,
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int line);
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#ifdef INVARIANT_SUPPORT
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void _mtx_assert(struct mtx *m, int what, const char *file, int line);
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#endif
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/*
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* We define our machine-independent (unoptimized) mutex micro-operations
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* here, if they are not already defined in the machine-dependent mutex.h
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*/
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/* Actually obtain mtx_lock */
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#ifndef _obtain_lock
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#define _obtain_lock(mp, tid) \
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atomic_cmpset_acq_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED, (tid))
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#endif
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/* Actually release mtx_lock */
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#ifndef _release_lock
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#define _release_lock(mp, tid) \
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atomic_cmpset_rel_ptr(&(mp)->mtx_lock, (tid), (void *)MTX_UNOWNED)
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#endif
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/* Actually release mtx_lock quickly, assuming we own it. */
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#ifndef _release_lock_quick
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#define _release_lock_quick(mp) \
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atomic_store_rel_ptr(&(mp)->mtx_lock, (void *)MTX_UNOWNED)
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#endif
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/*
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* Obtain a sleep lock inline, or call the "hard" function if we can't get it
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* easy.
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*/
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#ifndef _get_sleep_lock
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#define _get_sleep_lock(mp, tid, opts, file, line) do { \
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struct thread *_tid = (tid); \
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\
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if (!_obtain_lock((mp), _tid)) \
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_mtx_lock_sleep((mp), _tid, (opts), (file), (line)); \
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} while (0)
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#endif
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/*
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* Obtain a spin lock inline, or call the "hard" function if we can't get it
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* easy. For spinlocks, we handle recursion inline (it turns out that function
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* calls can be significantly expensive on some architectures).
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* Since spin locks are not _too_ common, inlining this code is not too big
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* a deal.
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*/
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#ifndef _get_spin_lock
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#ifdef SMP
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#define _get_spin_lock(mp, tid, opts, file, line) do { \
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struct thread *_tid = (tid); \
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\
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critical_enter(); \
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if (!_obtain_lock((mp), _tid)) { \
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if ((mp)->mtx_lock == (uintptr_t)_tid) \
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(mp)->mtx_recurse++; \
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else \
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_mtx_lock_spin((mp), _tid, (opts), (file), (line)); \
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} \
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} while (0)
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#else /* SMP */
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#define _get_spin_lock(mp, tid, opts, file, line) do { \
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struct thread *_tid = (tid); \
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\
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critical_enter(); \
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if ((mp)->mtx_lock == (uintptr_t)_tid) \
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(mp)->mtx_recurse++; \
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else { \
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KASSERT((mp)->mtx_lock == MTX_UNOWNED, ("corrupt spinlock")); \
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(mp)->mtx_lock = (uintptr_t)_tid; \
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} \
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} while (0)
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#endif /* SMP */
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#endif
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/*
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* Release a sleep lock inline, or call the "hard" function if we can't do it
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* easy.
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*/
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#ifndef _rel_sleep_lock
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#define _rel_sleep_lock(mp, tid, opts, file, line) do { \
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if (!_release_lock((mp), (tid))) \
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_mtx_unlock_sleep((mp), (opts), (file), (line)); \
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} while (0)
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#endif
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/*
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* For spinlocks, we can handle everything inline, as it's pretty simple and
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* a function call would be too expensive (at least on some architectures).
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* Since spin locks are not _too_ common, inlining this code is not too big
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* a deal.
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*
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* Since we always perform a critical_enter() when attempting to acquire a
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* spin lock, we need to always perform a matching critical_exit() when
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* releasing a spin lock. This includes the recursion cases.
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*/
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#ifndef _rel_spin_lock
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#ifdef SMP
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#define _rel_spin_lock(mp) do { \
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if (mtx_recursed((mp))) \
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(mp)->mtx_recurse--; \
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else \
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_release_lock_quick((mp)); \
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critical_exit(); \
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} while (0)
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#else /* SMP */
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#define _rel_spin_lock(mp) do { \
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if (mtx_recursed((mp))) \
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(mp)->mtx_recurse--; \
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else \
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(mp)->mtx_lock = MTX_UNOWNED; \
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critical_exit(); \
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} while (0)
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#endif /* SMP */
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#endif
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/*
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* Exported lock manipulation interface.
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*
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* mtx_lock(m) locks MTX_DEF mutex `m'
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*
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* mtx_lock_spin(m) locks MTX_SPIN mutex `m'
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*
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* mtx_unlock(m) unlocks MTX_DEF mutex `m'
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*
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* mtx_unlock_spin(m) unlocks MTX_SPIN mutex `m'
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*
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* mtx_lock_spin_flags(m, opts) and mtx_lock_flags(m, opts) locks mutex `m'
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* and passes option flags `opts' to the "hard" function, if required.
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* With these routines, it is possible to pass flags such as MTX_QUIET
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* to the appropriate lock manipulation routines.
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*
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* mtx_trylock(m) attempts to acquire MTX_DEF mutex `m' but doesn't sleep if
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* it cannot. Rather, it returns 0 on failure and non-zero on success.
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* It does NOT handle recursion as we assume that if a caller is properly
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* using this part of the interface, he will know that the lock in question
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* is _not_ recursed.
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*
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* mtx_trylock_flags(m, opts) is used the same way as mtx_trylock() but accepts
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* relevant option flags `opts.'
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*
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* mtx_initialized(m) returns non-zero if the lock `m' has been initialized.
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*
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* mtx_owned(m) returns non-zero if the current thread owns the lock `m'
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*
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* mtx_recursed(m) returns non-zero if the lock `m' is presently recursed.
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*/
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#define mtx_lock(m) mtx_lock_flags((m), 0)
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#define mtx_lock_spin(m) mtx_lock_spin_flags((m), 0)
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#define mtx_trylock(m) mtx_trylock_flags((m), 0)
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#define mtx_unlock(m) mtx_unlock_flags((m), 0)
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#define mtx_unlock_spin(m) mtx_unlock_spin_flags((m), 0)
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struct mtx_pool;
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struct mtx_pool *mtx_pool_create(const char *mtx_name, int pool_size, int opts);
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void mtx_pool_destroy(struct mtx_pool **poolp);
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struct mtx *mtx_pool_find(struct mtx_pool *pool, void *ptr);
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struct mtx *mtx_pool_alloc(struct mtx_pool *pool);
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#define mtx_pool_lock(pool, ptr) \
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mtx_lock(mtx_pool_find((pool), (ptr)))
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#define mtx_pool_lock_spin(pool, ptr) \
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mtx_lock_spin(mtx_pool_find((pool), (ptr)))
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#define mtx_pool_unlock(pool, ptr) \
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mtx_unlock(mtx_pool_find((pool), (ptr)))
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#define mtx_pool_unlock_spin(pool, ptr) \
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mtx_unlock_spin(mtx_pool_find((pool), (ptr)))
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/*
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* mtxpool_lockbuilder is a pool of sleep locks that is not witness
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* checked and should only be used for building higher level locks.
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*
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* mtxpool_sleep is a general purpose pool of sleep mutexes.
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*/
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extern struct mtx_pool *mtxpool_lockbuilder;
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extern struct mtx_pool *mtxpool_sleep;
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#ifndef LOCK_DEBUG
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#error LOCK_DEBUG not defined, include <sys/lock.h> before <sys/mutex.h>
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#endif
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#if LOCK_DEBUG > 0 || defined(MUTEX_NOINLINE)
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#define mtx_lock_flags(m, opts) \
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_mtx_lock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_flags(m, opts) \
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_mtx_unlock_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_lock_spin_flags(m, opts) \
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_mtx_lock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_spin_flags(m, opts) \
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_mtx_unlock_spin_flags((m), (opts), LOCK_FILE, LOCK_LINE)
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#else /* LOCK_DEBUG == 0 && !MUTEX_NOINLINE */
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#define mtx_lock_flags(m, opts) \
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_get_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_flags(m, opts) \
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_rel_sleep_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_lock_spin_flags(m, opts) \
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_get_spin_lock((m), curthread, (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_unlock_spin_flags(m, opts) \
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_rel_spin_lock((m))
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#endif /* LOCK_DEBUG > 0 || MUTEX_NOINLINE */
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#define mtx_trylock_flags(m, opts) \
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_mtx_trylock((m), (opts), LOCK_FILE, LOCK_LINE)
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#define mtx_initialized(m) ((m)->mtx_object.lo_flags & LO_INITIALIZED)
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#define mtx_owned(m) (((m)->mtx_lock & MTX_FLAGMASK) == (uintptr_t)curthread)
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#define mtx_recursed(m) ((m)->mtx_recurse != 0)
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#define mtx_name(m) ((m)->mtx_object.lo_name)
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/*
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* Global locks.
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*/
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extern struct mtx sched_lock;
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extern struct mtx Giant;
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/*
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* Giant lock manipulation and clean exit macros.
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* Used to replace return with an exit Giant and return.
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*
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* Note that DROP_GIANT*() needs to be paired with PICKUP_GIANT()
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* The #ifndef is to allow lint-like tools to redefine DROP_GIANT.
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*/
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#ifndef DROP_GIANT
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#define DROP_GIANT() \
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do { \
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int _giantcnt; \
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WITNESS_SAVE_DECL(Giant); \
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\
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if (mtx_owned(&Giant)) \
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WITNESS_SAVE(&Giant.mtx_object, Giant); \
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for (_giantcnt = 0; mtx_owned(&Giant); _giantcnt++) \
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mtx_unlock(&Giant)
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#define PICKUP_GIANT() \
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mtx_assert(&Giant, MA_NOTOWNED); \
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while (_giantcnt--) \
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mtx_lock(&Giant); \
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if (mtx_owned(&Giant)) \
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WITNESS_RESTORE(&Giant.mtx_object, Giant); \
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} while (0)
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#define PARTIAL_PICKUP_GIANT() \
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mtx_assert(&Giant, MA_NOTOWNED); \
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while (_giantcnt--) \
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mtx_lock(&Giant); \
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if (mtx_owned(&Giant)) \
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WITNESS_RESTORE(&Giant.mtx_object, Giant)
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#endif
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/*
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* Network MPSAFE temporary workarounds. When debug_mpsafenet
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* is 1 the network is assumed to operate without Giant on the
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* input path and protocols that require Giant must collect it
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* on entry. When 0 Giant is grabbed in the network interface
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* ISR's and in the netisr path and there is no need to grab
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* the Giant lock. Note that, unlike GIANT_PICKUP() and
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* GIANT_DROP(), these macros directly wrap mutex operations
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* without special recursion handling.
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*
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* This mechanism is intended as temporary until everything of
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* importance is properly locked. Note: the semantics for
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* NET_{LOCK,UNLOCK}_GIANT() are not the same as DROP_GIANT()
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* and PICKUP_GIANT(), as they are plain mutex operations
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* without a recursion counter.
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*/
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extern int debug_mpsafenet; /* defined in net/netisr.c */
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#define NET_LOCK_GIANT() do { \
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if (!debug_mpsafenet) \
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mtx_lock(&Giant); \
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} while (0)
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#define NET_UNLOCK_GIANT() do { \
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if (!debug_mpsafenet) \
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mtx_unlock(&Giant); \
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} while (0)
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#define NET_ASSERT_GIANT() do { \
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if (!debug_mpsafenet) \
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mtx_assert(&Giant, MA_OWNED); \
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} while (0)
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#define UGAR(rval) do { \
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int _val = (rval); \
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mtx_unlock(&Giant); \
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return (_val); \
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} while (0)
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struct mtx_args {
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struct mtx *ma_mtx;
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const char *ma_desc;
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int ma_opts;
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};
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#define MTX_SYSINIT(name, mtx, desc, opts) \
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static struct mtx_args name##_args = { \
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(mtx), \
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(desc), \
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(opts) \
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}; \
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SYSINIT(name##_mtx_sysinit, SI_SUB_LOCK, SI_ORDER_MIDDLE, \
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mtx_sysinit, &name##_args)
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/*
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* The INVARIANTS-enabled mtx_assert() functionality.
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*
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* The constants need to be defined for INVARIANT_SUPPORT infrastructure
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* support as _mtx_assert() itself uses them and the latter implies that
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* _mtx_assert() must build.
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*/
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#ifdef INVARIANT_SUPPORT
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#define MA_OWNED 0x01
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#define MA_NOTOWNED 0x02
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#define MA_RECURSED 0x04
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#define MA_NOTRECURSED 0x08
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#endif /* INVARIANT_SUPPORT */
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#ifdef INVARIANTS
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#define mtx_assert(m, what) \
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_mtx_assert((m), (what), __FILE__, __LINE__)
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#define GIANT_REQUIRED mtx_assert(&Giant, MA_OWNED)
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#else /* INVARIANTS */
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#define mtx_assert(m, what)
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#define GIANT_REQUIRED
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#endif /* INVARIANTS */
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/*
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* Common lock type names.
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*/
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#define MTX_NETWORK_LOCK "network driver"
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#endif /* _KERNEL */
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#endif /* !LOCORE */
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#endif /* _SYS_MUTEX_H_ */
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