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#ifndef _LINUX_MMAP_LOCK_H
#define _LINUX_MMAP_LOCK_H
#include <linux/lockdep.h>
#include <linux/mm_types.h>
#include <linux/mmdebug.h>
#include <linux/rwsem.h>
#include <linux/tracepoint-defs.h>
#include <linux/types.h>
#define MMAP_LOCK_INITIALIZER(name) \
.mmap_lock = __RWSEM_INITIALIZER((name).mmap_lock),
DECLARE_TRACEPOINT(mmap_lock_start_locking);
DECLARE_TRACEPOINT(mmap_lock_acquire_returned);
DECLARE_TRACEPOINT(mmap_lock_released);
#ifdef CONFIG_TRACING
void __mmap_lock_do_trace_start_locking(struct mm_struct *mm, bool write);
void __mmap_lock_do_trace_acquire_returned(struct mm_struct *mm, bool write,
bool success);
void __mmap_lock_do_trace_released(struct mm_struct *mm, bool write);
static inline void __mmap_lock_trace_start_locking(struct mm_struct *mm,
bool write)
{
if (tracepoint_enabled(mmap_lock_start_locking))
__mmap_lock_do_trace_start_locking(mm, write);
}
static inline void __mmap_lock_trace_acquire_returned(struct mm_struct *mm,
bool write, bool success)
{
if (tracepoint_enabled(mmap_lock_acquire_returned))
__mmap_lock_do_trace_acquire_returned(mm, write, success);
}
static inline void __mmap_lock_trace_released(struct mm_struct *mm, bool write)
{
if (tracepoint_enabled(mmap_lock_released))
__mmap_lock_do_trace_released(mm, write);
}
#else /* !CONFIG_TRACING */
static inline void __mmap_lock_trace_start_locking(struct mm_struct *mm,
bool write)
{
}
static inline void __mmap_lock_trace_acquire_returned(struct mm_struct *mm,
bool write, bool success)
{
}
static inline void __mmap_lock_trace_released(struct mm_struct *mm, bool write)
{
}
#endif /* CONFIG_TRACING */
static inline void mmap_assert_locked(struct mm_struct *mm)
{
lockdep_assert_held(&mm->mmap_lock);
VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
}
static inline void mmap_assert_write_locked(struct mm_struct *mm)
{
lockdep_assert_held_write(&mm->mmap_lock);
VM_BUG_ON_MM(!rwsem_is_locked(&mm->mmap_lock), mm);
}
#ifdef CONFIG_PER_VMA_LOCK
/*
* Drop all currently-held per-VMA locks.
* This is called from the mmap_lock implementation directly before releasing
* a write-locked mmap_lock (or downgrading it to read-locked).
* This should normally NOT be called manually from other places.
* If you want to call this manually anyway, keep in mind that this will release
* *all* VMA write locks, including ones from further up the stack.
*/
static inline void vma_end_write_all(struct mm_struct *mm)
{
mmap_assert_write_locked(mm);
/*
* Nobody can concurrently modify mm->mm_lock_seq due to exclusive
* mmap_lock being held.
* We need RELEASE semantics here to ensure that preceding stores into
* the VMA take effect before we unlock it with this store.
* Pairs with ACQUIRE semantics in vma_start_read().
*/
smp_store_release(&mm->mm_lock_seq, mm->mm_lock_seq + 1);
}
#else
static inline void vma_end_write_all(struct mm_struct *mm) {}
#endif
static inline void mmap_init_lock(struct mm_struct *mm)
{
init_rwsem(&mm->mmap_lock);
}
static inline void mmap_write_lock(struct mm_struct *mm)
{
__mmap_lock_trace_start_locking(mm, true);
down_write(&mm->mmap_lock);
__mmap_lock_trace_acquire_returned(mm, true, true);
}
static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
{
__mmap_lock_trace_start_locking(mm, true);
down_write_nested(&mm->mmap_lock, subclass);
__mmap_lock_trace_acquire_returned(mm, true, true);
}
static inline int mmap_write_lock_killable(struct mm_struct *mm)
{
int ret;
__mmap_lock_trace_start_locking(mm, true);
ret = down_write_killable(&mm->mmap_lock);
__mmap_lock_trace_acquire_returned(mm, true, ret == 0);
return ret;
}
static inline void mmap_write_unlock(struct mm_struct *mm)
{
__mmap_lock_trace_released(mm, true);
vma_end_write_all(mm);
up_write(&mm->mmap_lock);
}
static inline void mmap_write_downgrade(struct mm_struct *mm)
{
__mmap_lock_trace_acquire_returned(mm, false, true);
vma_end_write_all(mm);
downgrade_write(&mm->mmap_lock);
}
static inline void mmap_read_lock(struct mm_struct *mm)
{
__mmap_lock_trace_start_locking(mm, false);
down_read(&mm->mmap_lock);
__mmap_lock_trace_acquire_returned(mm, false, true);
}
static inline int mmap_read_lock_killable(struct mm_struct *mm)
{
int ret;
__mmap_lock_trace_start_locking(mm, false);
ret = down_read_killable(&mm->mmap_lock);
__mmap_lock_trace_acquire_returned(mm, false, ret == 0);
return ret;
}
static inline bool mmap_read_trylock(struct mm_struct *mm)
{
bool ret;
__mmap_lock_trace_start_locking(mm, false);
ret = down_read_trylock(&mm->mmap_lock) != 0;
__mmap_lock_trace_acquire_returned(mm, false, ret);
return ret;
}
static inline void mmap_read_unlock(struct mm_struct *mm)
{
__mmap_lock_trace_released(mm, false);
up_read(&mm->mmap_lock);
}
static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
{
__mmap_lock_trace_released(mm, false);
up_read_non_owner(&mm->mmap_lock);
}
static inline int mmap_lock_is_contended(struct mm_struct *mm)
{
return rwsem_is_contended(&mm->mmap_lock);
}
#endif /* _LINUX_MMAP_LOCK_H */
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