| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
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| 2 | #ifndef __LINUX_MUTEX_TYPES_H |
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| 3 | #define __LINUX_MUTEX_TYPES_H |
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| 4 | |
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| 5 | #include <linux/atomic.h> |
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| 6 | #include <linux/lockdep_types.h> |
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| 7 | #include <linux/osq_lock.h> |
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| 8 | #include <linux/spinlock_types.h> |
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| 9 | #include <linux/types.h> |
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| 10 | |
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| 11 | #ifndef CONFIG_PREEMPT_RT |
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| 12 | |
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| 13 | /* |
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| 14 | * Simple, straightforward mutexes with strict semantics: |
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| 15 | * |
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| 16 | * - only one task can hold the mutex at a time |
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| 17 | * - only the owner can unlock the mutex |
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| 18 | * - multiple unlocks are not permitted |
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| 19 | * - recursive locking is not permitted |
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| 20 | * - a mutex object must be initialized via the API |
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| 21 | * - a mutex object must not be initialized via memset or copying |
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| 22 | * - task may not exit with mutex held |
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| 23 | * - memory areas where held locks reside must not be freed |
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| 24 | * - held mutexes must not be reinitialized |
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| 25 | * - mutexes may not be used in hardware or software interrupt |
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| 26 | * contexts such as tasklets and timers |
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| 27 | * |
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| 28 | * These semantics are fully enforced when DEBUG_MUTEXES is |
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| 29 | * enabled. Furthermore, besides enforcing the above rules, the mutex |
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| 30 | * debugging code also implements a number of additional features |
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| 31 | * that make lock debugging easier and faster: |
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| 32 | * |
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| 33 | * - uses symbolic names of mutexes, whenever they are printed in debug output |
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| 34 | * - point-of-acquire tracking, symbolic lookup of function names |
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| 35 | * - list of all locks held in the system, printout of them |
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| 36 | * - owner tracking |
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| 37 | * - detects self-recursing locks and prints out all relevant info |
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| 38 | * - detects multi-task circular deadlocks and prints out all affected |
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| 39 | * locks and tasks (and only those tasks) |
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| 40 | */ |
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| 41 | struct mutex { |
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| 42 | atomic_long_t owner; |
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| 43 | raw_spinlock_t wait_lock; |
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| 44 | #ifdef CONFIG_MUTEX_SPIN_ON_OWNER |
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| 45 | struct optimistic_spin_queue osq; /* Spinner MCS lock */ |
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| 46 | #endif |
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| 47 | struct list_head wait_list; |
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| 48 | #ifdef CONFIG_DEBUG_MUTEXES |
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| 49 | void *magic; |
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| 50 | #endif |
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| 51 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
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| 52 | struct lockdep_map dep_map; |
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| 53 | #endif |
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| 54 | }; |
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| 55 | |
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| 56 | #else /* !CONFIG_PREEMPT_RT */ |
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| 57 | /* |
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| 58 | * Preempt-RT variant based on rtmutexes. |
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| 59 | */ |
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| 60 | #include <linux/rtmutex.h> |
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| 61 | |
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| 62 | struct mutex { |
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| 63 | struct rt_mutex_base rtmutex; |
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| 64 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
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| 65 | struct lockdep_map dep_map; |
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| 66 | #endif |
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| 67 | }; |
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| 68 | |
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| 69 | #endif /* CONFIG_PREEMPT_RT */ |
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| 70 | |
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| 71 | #endif /* __LINUX_MUTEX_TYPES_H */ |
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| 72 | |
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