Messages in this thread | | | Date | Wed, 1 Apr 2020 15:46:33 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 07/10] mmap locking API: add mmap_read_release() and mmap_read_unlock_non_owner() |
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On Fri, Mar 27, 2020 at 03:50:59PM -0700, Michel Lespinasse wrote: > Add a couple APIs to allow splitting mmap_read_unlock() into two calls: > - mmap_read_release(), called by the task that had taken the mmap lock; > - mmap_read_unlock_non_owner(), called from a work queue. > > These apis are used by kernel/bpf/stackmap.c only.
That code is an absolute abomination and should never have gotten merged.
That said; I would prefer a mmap_read_trylock_nonowner() over mmap_read_release() existing.
> Signed-off-by: Michel Lespinasse <walken@google.com> > --- > include/linux/mmap_lock.h | 10 ++++++++++ > kernel/bpf/stackmap.c | 9 ++++----- > 2 files changed, 14 insertions(+), 5 deletions(-) > > diff --git a/include/linux/mmap_lock.h b/include/linux/mmap_lock.h > index 36fb758401d6..a80cf9695514 100644 > --- a/include/linux/mmap_lock.h > +++ b/include/linux/mmap_lock.h > @@ -62,4 +62,14 @@ static inline void mmap_read_unlock(struct mm_struct *mm) > up_read(&mm->mmap_sem); > } > > +static inline void mmap_read_release(struct mm_struct *mm, unsigned long ip) > +{ > + rwsem_release(&mm->mmap_sem.dep_map, ip); > +} > + > +static inline void mmap_read_unlock_non_owner(struct mm_struct *mm) > +{ > + up_read_non_owner(&mm->mmap_sem); > +} > + > #endif /* _LINUX_MMAP_LOCK_H */
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