0cc55a0213
Add a couple APIs used by kernel/bpf/stackmap.c only: - mmap_read_trylock_non_owner() - mmap_read_unlock_non_owner() (may be called from a work queue). It's still not ideal that bpf/stackmap subverts the lock ownership in this way. Thanks to Peter Zijlstra for suggesting this API as the least-ugly way of addressing this in the short term. Signed-off-by: Michel Lespinasse <walken@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Davidlohr Bueso <dbueso@suse.de> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hughd@google.com> Cc: Jason Gunthorpe <jgg@ziepe.ca> Cc: Jerome Glisse <jglisse@redhat.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Laurent Dufour <ldufour@linux.ibm.com> Cc: Liam Howlett <Liam.Howlett@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ying Han <yinghan@google.com> Link: http://lkml.kernel.org/r/20200520052908.204642-8-walken@google.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
74 lines
1.5 KiB
C
74 lines
1.5 KiB
C
#ifndef _LINUX_MMAP_LOCK_H
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#define _LINUX_MMAP_LOCK_H
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static inline void mmap_init_lock(struct mm_struct *mm)
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{
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init_rwsem(&mm->mmap_sem);
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}
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static inline void mmap_write_lock(struct mm_struct *mm)
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{
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down_write(&mm->mmap_sem);
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}
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static inline void mmap_write_lock_nested(struct mm_struct *mm, int subclass)
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{
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down_write_nested(&mm->mmap_sem, subclass);
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}
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static inline int mmap_write_lock_killable(struct mm_struct *mm)
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{
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return down_write_killable(&mm->mmap_sem);
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}
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static inline bool mmap_write_trylock(struct mm_struct *mm)
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{
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return down_write_trylock(&mm->mmap_sem) != 0;
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}
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static inline void mmap_write_unlock(struct mm_struct *mm)
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{
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up_write(&mm->mmap_sem);
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}
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static inline void mmap_write_downgrade(struct mm_struct *mm)
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{
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downgrade_write(&mm->mmap_sem);
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}
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static inline void mmap_read_lock(struct mm_struct *mm)
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{
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down_read(&mm->mmap_sem);
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}
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static inline int mmap_read_lock_killable(struct mm_struct *mm)
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{
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return down_read_killable(&mm->mmap_sem);
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}
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static inline bool mmap_read_trylock(struct mm_struct *mm)
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{
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return down_read_trylock(&mm->mmap_sem) != 0;
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}
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static inline void mmap_read_unlock(struct mm_struct *mm)
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{
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up_read(&mm->mmap_sem);
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}
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static inline bool mmap_read_trylock_non_owner(struct mm_struct *mm)
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{
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if (down_read_trylock(&mm->mmap_sem)) {
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rwsem_release(&mm->mmap_sem.dep_map, _RET_IP_);
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return true;
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}
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return false;
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}
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static inline void mmap_read_unlock_non_owner(struct mm_struct *mm)
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{
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up_read_non_owner(&mm->mmap_sem);
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}
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#endif /* _LINUX_MMAP_LOCK_H */
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