xref: /openbmc/linux/include/linux/mmap_lock.h (revision a0936e9e) 
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_assert_locked(struct mm_struct *mm)
64 {
65 	lockdep_assert_held(&mm->mmap_lock);
66 	VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
67 }
68 
69 static inline void mmap_assert_write_locked(struct mm_struct *mm)
70 {
71 	lockdep_assert_held_write(&mm->mmap_lock);
72 	VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
73 }
74 
75 #ifdef CONFIG_PER_VMA_LOCK
76 static inline void vma_end_write_all(struct mm_struct *mm)
77 {
78 	mmap_assert_write_locked(mm);
79 	/* No races during update due to exclusive mmap_lock being held */
80 	WRITE_ONCE(mm->mm_lock_seq, mm->mm_lock_seq + 1);
81 }
82 #else
83 static inline void vma_end_write_all(struct mm_struct *mm) {}
84 #endif
85 
86 static inline void mmap_init_lock(struct mm_struct *mm)
87 {
88 	init_rwsem(&mm->mmap_lock);
89 }
90 
91 static inline void mmap_write_lock(struct mm_struct *mm)
92 {
93 	__mmap_lock_trace_start_locking(mm, true);
94 	down_write(&mm->mmap_lock);
95 	__mmap_lock_trace_acquire_returned(mm, true, true);
96 }
97 
98 static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
99 {
100 	__mmap_lock_trace_start_locking(mm, true);
101 	down_write_nested(&mm->mmap_lock, subclass);
102 	__mmap_lock_trace_acquire_returned(mm, true, true);
103 }
104 
105 static inline int mmap_write_lock_killable(struct mm_struct *mm)
106 {
107 	int ret;
108 
109 	__mmap_lock_trace_start_locking(mm, true);
110 	ret = down_write_killable(&mm->mmap_lock);
111 	__mmap_lock_trace_acquire_returned(mm, true, ret == 0);
112 	return ret;
113 }
114 
115 static inline bool mmap_write_trylock(struct mm_struct *mm)
116 {
117 	bool ret;
118 
119 	__mmap_lock_trace_start_locking(mm, true);
120 	ret = down_write_trylock(&mm->mmap_lock) != 0;
121 	__mmap_lock_trace_acquire_returned(mm, true, ret);
122 	return ret;
123 }
124 
125 static inline void mmap_write_unlock(struct mm_struct *mm)
126 {
127 	__mmap_lock_trace_released(mm, true);
128 	vma_end_write_all(mm);
129 	up_write(&mm->mmap_lock);
130 }
131 
132 static inline void mmap_write_downgrade(struct mm_struct *mm)
133 {
134 	__mmap_lock_trace_acquire_returned(mm, false, true);
135 	vma_end_write_all(mm);
136 	downgrade_write(&mm->mmap_lock);
137 }
138 
139 static inline void mmap_read_lock(struct mm_struct *mm)
140 {
141 	__mmap_lock_trace_start_locking(mm, false);
142 	down_read(&mm->mmap_lock);
143 	__mmap_lock_trace_acquire_returned(mm, false, true);
144 }
145 
146 static inline int mmap_read_lock_killable(struct mm_struct *mm)
147 {
148 	int ret;
149 
150 	__mmap_lock_trace_start_locking(mm, false);
151 	ret = down_read_killable(&mm->mmap_lock);
152 	__mmap_lock_trace_acquire_returned(mm, false, ret == 0);
153 	return ret;
154 }
155 
156 static inline bool mmap_read_trylock(struct mm_struct *mm)
157 {
158 	bool ret;
159 
160 	__mmap_lock_trace_start_locking(mm, false);
161 	ret = down_read_trylock(&mm->mmap_lock) != 0;
162 	__mmap_lock_trace_acquire_returned(mm, false, ret);
163 	return ret;
164 }
165 
166 static inline void mmap_read_unlock(struct mm_struct *mm)
167 {
168 	__mmap_lock_trace_released(mm, false);
169 	up_read(&mm->mmap_lock);
170 }
171 
172 static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
173 {
174 	__mmap_lock_trace_released(mm, false);
175 	up_read_non_owner(&mm->mmap_lock);
176 }
177 
178 static inline int mmap_lock_is_contended(struct mm_struct *mm)
179 {
180 	return rwsem_is_contended(&mm->mmap_lock);
181 }
182 
183 #endif /* _LINUX_MMAP_LOCK_H */
184