4f688d19fb
Add support for using mutexes during KDB and shutdown. This is also required for doing mode-switching during panic for drm-next. Add new mutex functions mutex_init_witness() and mutex_destroy() allowing LinuxKPI mutexes to be tracked by witness. Declare mutex_is_locked() and mutex_is_owned() like inline functions to get cleaner warnings. These functions are used inside WARN_ON() statements which might look a bit odd if these functions get fully expanded. Give mutexes better debug names through the mutex_name() macro when WITNESS_ALL is defined. The mutex_name() macro can prefix parts of the filename and line number before the mutex name. MFC after: 1 week Sponsored by: Mellanox Technologies
132 lines
3.6 KiB
C
132 lines
3.6 KiB
C
/*-
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* Copyright (c) 2010 Isilon Systems, Inc.
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* Copyright (c) 2010 iX Systems, Inc.
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* Copyright (c) 2010 Panasas, Inc.
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* Copyright (c) 2013-2017 Mellanox Technologies, Ltd.
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* 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 unmodified, this list of conditions, and the following
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* 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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _LINUX_MUTEX_H_
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#define _LINUX_MUTEX_H_
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#include <sys/param.h>
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#include <sys/proc.h>
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#include <sys/lock.h>
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#include <sys/sx.h>
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#include <linux/spinlock.h>
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typedef struct mutex {
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struct sx sx;
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} mutex_t;
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/*
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* By defining CONFIG_NO_MUTEX_SKIP LinuxKPI mutexes and asserts will
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* not be skipped during panic().
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*/
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#ifdef CONFIG_NO_MUTEX_SKIP
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#define MUTEX_SKIP(void) 0
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#else
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#define MUTEX_SKIP(void) unlikely(SCHEDULER_STOPPED() || kdb_active)
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#endif
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#define mutex_lock(_m) do { \
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if (MUTEX_SKIP()) \
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break; \
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sx_xlock(&(_m)->sx); \
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} while (0)
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#define mutex_lock_nested(_m, _s) mutex_lock(_m)
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#define mutex_lock_nest_lock(_m, _s) mutex_lock(_m)
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#define mutex_lock_interruptible(_m) ({ \
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MUTEX_SKIP() ? 0 : \
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(sx_xlock_sig(&(_m)->sx) ? -EINTR : 0); \
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})
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#define mutex_unlock(_m) do { \
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if (MUTEX_SKIP()) \
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break; \
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sx_xunlock(&(_m)->sx); \
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} while (0)
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#define mutex_trylock(_m) ({ \
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MUTEX_SKIP() ? 1 : \
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!!sx_try_xlock(&(_m)->sx); \
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})
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#define mutex_init(_m) \
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linux_mutex_init(_m, mutex_name(#_m), SX_NOWITNESS)
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#define mutex_init_witness(_m) \
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linux_mutex_init(_m, mutex_name(#_m), SX_DUPOK)
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#define mutex_destroy(_m) \
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linux_mutex_destroy(_m)
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static inline bool
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mutex_is_locked(mutex_t *m)
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{
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return ((struct thread *)SX_OWNER(m->sx.sx_lock) != NULL);
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}
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static inline bool
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mutex_is_owned(mutex_t *m)
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{
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return (sx_xlocked(&m->sx));
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}
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#ifdef WITNESS_ALL
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/* NOTE: the maximum WITNESS name is 64 chars */
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#define __mutex_name(name, file, line) \
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(((const char *){file ":" #line "-" name}) + \
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(sizeof(file) > 16 ? sizeof(file) - 16 : 0))
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#else
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#define __mutex_name(name, file, line) name
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#endif
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#define _mutex_name(...) __mutex_name(__VA_ARGS__)
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#define mutex_name(name) _mutex_name(name, __FILE__, __LINE__)
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#define DEFINE_MUTEX(lock) \
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mutex_t lock; \
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SX_SYSINIT_FLAGS(lock, &(lock).sx, mutex_name(#lock), SX_DUPOK)
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static inline void
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linux_mutex_init(mutex_t *m, const char *name, int flags)
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{
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memset(m, 0, sizeof(*m));
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sx_init_flags(&m->sx, name, flags);
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}
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static inline void
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linux_mutex_destroy(mutex_t *m)
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{
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if (mutex_is_owned(m))
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mutex_unlock(m);
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sx_destroy(&m->sx);
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}
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#endif /* _LINUX_MUTEX_H_ */
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