include/linux/mmap_lock.h

   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 */