186 lines · c
1#ifndef _LINUX_MMAP_LOCK_H2#define _LINUX_MMAP_LOCK_H3 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 14DECLARE_TRACEPOINT(mmap_lock_start_locking);15DECLARE_TRACEPOINT(mmap_lock_acquire_returned);16DECLARE_TRACEPOINT(mmap_lock_released);17 18#ifdef CONFIG_TRACING19 20void __mmap_lock_do_trace_start_locking(struct mm_struct *mm, bool write);21void __mmap_lock_do_trace_acquire_returned(struct mm_struct *mm, bool write,22 bool success);23void __mmap_lock_do_trace_released(struct mm_struct *mm, bool write);24 25static 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 32static 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 39static 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 47static inline void __mmap_lock_trace_start_locking(struct mm_struct *mm,48 bool write)49{50}51 52static inline void __mmap_lock_trace_acquire_returned(struct mm_struct *mm,53 bool write, bool success)54{55}56 57static inline void __mmap_lock_trace_released(struct mm_struct *mm, bool write)58{59}60 61#endif /* CONFIG_TRACING */62 63static inline void mmap_assert_locked(const struct mm_struct *mm)64{65 rwsem_assert_held(&mm->mmap_lock);66}67 68static inline void mmap_assert_write_locked(const struct mm_struct *mm)69{70 rwsem_assert_held_write(&mm->mmap_lock);71}72 73#ifdef CONFIG_PER_VMA_LOCK74/*75 * Drop all currently-held per-VMA locks.76 * This is called from the mmap_lock implementation directly before releasing77 * a write-locked mmap_lock (or downgrading it to read-locked).78 * This should normally NOT be called manually from other places.79 * If you want to call this manually anyway, keep in mind that this will release80 * *all* VMA write locks, including ones from further up the stack.81 */82static inline void vma_end_write_all(struct mm_struct *mm)83{84 mmap_assert_write_locked(mm);85 /*86 * Nobody can concurrently modify mm->mm_lock_seq due to exclusive87 * mmap_lock being held.88 * We need RELEASE semantics here to ensure that preceding stores into89 * the VMA take effect before we unlock it with this store.90 * Pairs with ACQUIRE semantics in vma_start_read().91 */92 smp_store_release(&mm->mm_lock_seq, mm->mm_lock_seq + 1);93}94#else95static inline void vma_end_write_all(struct mm_struct *mm) {}96#endif97 98static inline void mmap_init_lock(struct mm_struct *mm)99{100 init_rwsem(&mm->mmap_lock);101}102 103static inline void mmap_write_lock(struct mm_struct *mm)104{105 __mmap_lock_trace_start_locking(mm, true);106 down_write(&mm->mmap_lock);107 __mmap_lock_trace_acquire_returned(mm, true, true);108}109 110static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)111{112 __mmap_lock_trace_start_locking(mm, true);113 down_write_nested(&mm->mmap_lock, subclass);114 __mmap_lock_trace_acquire_returned(mm, true, true);115}116 117static inline int mmap_write_lock_killable(struct mm_struct *mm)118{119 int ret;120 121 __mmap_lock_trace_start_locking(mm, true);122 ret = down_write_killable(&mm->mmap_lock);123 __mmap_lock_trace_acquire_returned(mm, true, ret == 0);124 return ret;125}126 127static inline void mmap_write_unlock(struct mm_struct *mm)128{129 __mmap_lock_trace_released(mm, true);130 vma_end_write_all(mm);131 up_write(&mm->mmap_lock);132}133 134static inline void mmap_write_downgrade(struct mm_struct *mm)135{136 __mmap_lock_trace_acquire_returned(mm, false, true);137 vma_end_write_all(mm);138 downgrade_write(&mm->mmap_lock);139}140 141static inline void mmap_read_lock(struct mm_struct *mm)142{143 __mmap_lock_trace_start_locking(mm, false);144 down_read(&mm->mmap_lock);145 __mmap_lock_trace_acquire_returned(mm, false, true);146}147 148static inline int mmap_read_lock_killable(struct mm_struct *mm)149{150 int ret;151 152 __mmap_lock_trace_start_locking(mm, false);153 ret = down_read_killable(&mm->mmap_lock);154 __mmap_lock_trace_acquire_returned(mm, false, ret == 0);155 return ret;156}157 158static inline bool mmap_read_trylock(struct mm_struct *mm)159{160 bool ret;161 162 __mmap_lock_trace_start_locking(mm, false);163 ret = down_read_trylock(&mm->mmap_lock) != 0;164 __mmap_lock_trace_acquire_returned(mm, false, ret);165 return ret;166}167 168static inline void mmap_read_unlock(struct mm_struct *mm)169{170 __mmap_lock_trace_released(mm, false);171 up_read(&mm->mmap_lock);172}173 174static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)175{176 __mmap_lock_trace_released(mm, false);177 up_read_non_owner(&mm->mmap_lock);178}179 180static inline int mmap_lock_is_contended(struct mm_struct *mm)181{182 return rwsem_is_contended(&mm->mmap_lock);183}184 185#endif /* _LINUX_MMAP_LOCK_H */186