xref: /openbmc/linux/include/linux/mmap_lock.h (revision 76a4f7cc) 
1 #ifndef _LINUX_MMAP_LOCK_H
2 #define _LINUX_MMAP_LOCK_H
3 
4 #include <linux/lockdep.h>
5 #include <linux/mm_types.h>
6 #include <linux/mmdebug.h>
7 #include <linux/rwsem.h>
8 #include <linux/tracepoint-defs.h>
9 #include <linux/types.h>
10 
11 #define MMAP_LOCK_INITIALIZER(name) \
12 	.mmap_lock = __RWSEM_INITIALIZER((name).mmap_lock),
13 
14 DECLARE_TRACEPOINT(mmap_lock_start_locking);
15 DECLARE_TRACEPOINT(mmap_lock_acquire_returned);
16 DECLARE_TRACEPOINT(mmap_lock_released);
17 
18 #ifdef CONFIG_TRACING
19 
20 void __mmap_lock_do_trace_start_locking(struct mm_struct *mm, bool write);
21 void __mmap_lock_do_trace_acquire_returned(struct mm_struct *mm, bool write,
22 					   bool success);
23 void __mmap_lock_do_trace_released(struct mm_struct *mm, bool write);
24 
25 static inline void __mmap_lock_trace_start_locking(struct mm_struct *mm,
26 						   bool write)
27 {
28 	if (tracepoint_enabled(mmap_lock_start_locking))
29 		__mmap_lock_do_trace_start_locking(mm, write);
30 }
31 
32 static inline void __mmap_lock_trace_acquire_returned(struct mm_struct *mm,
33 						      bool write, bool success)
34 {
35 	if (tracepoint_enabled(mmap_lock_acquire_returned))
36 		__mmap_lock_do_trace_acquire_returned(mm, write, success);
37 }
38 
39 static inline void __mmap_lock_trace_released(struct mm_struct *mm, bool write)
40 {
41 	if (tracepoint_enabled(mmap_lock_released))
42 		__mmap_lock_do_trace_released(mm, write);
43 }
44 
45 #else /* !CONFIG_TRACING */
46 
47 static inline void __mmap_lock_trace_start_locking(struct mm_struct *mm,
48 						   bool write)
49 {
50 }
51 
52 static inline void __mmap_lock_trace_acquire_returned(struct mm_struct *mm,
53 						      bool write, bool success)
54 {
55 }
56 
57 static inline void __mmap_lock_trace_released(struct mm_struct *mm, bool write)
58 {
59 }
60 
61 #endif /* CONFIG_TRACING */
62 
63 static inline void mmap_init_lock(struct mm_struct *mm)
64 {
65 	init_rwsem(&mm->mmap_lock);
66 }
67 
68 static inline void mmap_write_lock(struct mm_struct *mm)
69 {
70 	__mmap_lock_trace_start_locking(mm, true);
71 	down_write(&mm->mmap_lock);
72 	__mmap_lock_trace_acquire_returned(mm, true, true);
73 }
74 
75 static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
76 {
77 	__mmap_lock_trace_start_locking(mm, true);
78 	down_write_nested(&mm->mmap_lock, subclass);
79 	__mmap_lock_trace_acquire_returned(mm, true, true);
80 }
81 
82 static inline int mmap_write_lock_killable(struct mm_struct *mm)
83 {
84 	int ret;
85 
86 	__mmap_lock_trace_start_locking(mm, true);
87 	ret = down_write_killable(&mm->mmap_lock);
88 	__mmap_lock_trace_acquire_returned(mm, true, ret == 0);
89 	return ret;
90 }
91 
92 static inline bool mmap_write_trylock(struct mm_struct *mm)
93 {
94 	bool ret;
95 
96 	__mmap_lock_trace_start_locking(mm, true);
97 	ret = down_write_trylock(&mm->mmap_lock) != 0;
98 	__mmap_lock_trace_acquire_returned(mm, true, ret);
99 	return ret;
100 }
101 
102 static inline void mmap_write_unlock(struct mm_struct *mm)
103 {
104 	__mmap_lock_trace_released(mm, true);
105 	up_write(&mm->mmap_lock);
106 }
107 
108 static inline void mmap_write_downgrade(struct mm_struct *mm)
109 {
110 	__mmap_lock_trace_acquire_returned(mm, false, true);
111 	downgrade_write(&mm->mmap_lock);
112 }
113 
114 static inline void mmap_read_lock(struct mm_struct *mm)
115 {
116 	__mmap_lock_trace_start_locking(mm, false);
117 	down_read(&mm->mmap_lock);
118 	__mmap_lock_trace_acquire_returned(mm, false, true);
119 }
120 
121 static inline int mmap_read_lock_killable(struct mm_struct *mm)
122 {
123 	int ret;
124 
125 	__mmap_lock_trace_start_locking(mm, false);
126 	ret = down_read_killable(&mm->mmap_lock);
127 	__mmap_lock_trace_acquire_returned(mm, false, ret == 0);
128 	return ret;
129 }
130 
131 static inline bool mmap_read_trylock(struct mm_struct *mm)
132 {
133 	bool ret;
134 
135 	__mmap_lock_trace_start_locking(mm, false);
136 	ret = down_read_trylock(&mm->mmap_lock) != 0;
137 	__mmap_lock_trace_acquire_returned(mm, false, ret);
138 	return ret;
139 }
140 
141 static inline void mmap_read_unlock(struct mm_struct *mm)
142 {
143 	__mmap_lock_trace_released(mm, false);
144 	up_read(&mm->mmap_lock);
145 }
146 
147 static inline bool mmap_read_trylock_non_owner(struct mm_struct *mm)
148 {
149 	if (mmap_read_trylock(mm)) {
150 		rwsem_release(&mm->mmap_lock.dep_map, _RET_IP_);
151 		return true;
152 	}
153 	return false;
154 }
155 
156 static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
157 {
158 	__mmap_lock_trace_released(mm, false);
159 	up_read_non_owner(&mm->mmap_lock);
160 }
161 
162 static inline void mmap_assert_locked(struct mm_struct *mm)
163 {
164 	lockdep_assert_held(&mm->mmap_lock);
165 	VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
166 }
167 
168 static inline void mmap_assert_write_locked(struct mm_struct *mm)
169 {
170 	lockdep_assert_held_write(&mm->mmap_lock);
171 	VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
172 }
173 
174 static inline int mmap_lock_is_contended(struct mm_struct *mm)
175 {
176 	return rwsem_is_contended(&mm->mmap_lock);
177 }
178 
179 #endif /* _LINUX_MMAP_LOCK_H */
180