Messages in this thread | | | From | Ian Rogers <> | Date | Wed, 20 Jul 2022 08:36:18 -0700 | Subject | Re: [PATCH v3 10/14] locking/percpu-rwsem: Add percpu_is_write_locked() and percpu_is_read_locked() |
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On Mon, Jul 4, 2022 at 8:07 AM Marco Elver <elver@google.com> wrote: > > Implement simple accessors to probe percpu-rwsem's locked state: > percpu_is_write_locked(), percpu_is_read_locked(). > > Signed-off-by: Marco Elver <elver@google.com> > Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Ian Rogers <irogers@google.com>
Thanks, Ian
> --- > v2: > * New patch. > --- > include/linux/percpu-rwsem.h | 6 ++++++ > kernel/locking/percpu-rwsem.c | 6 ++++++ > 2 files changed, 12 insertions(+) > > diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h > index 5fda40f97fe9..36b942b67b7d 100644 > --- a/include/linux/percpu-rwsem.h > +++ b/include/linux/percpu-rwsem.h > @@ -121,9 +121,15 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem) > preempt_enable(); > } > > +extern bool percpu_is_read_locked(struct percpu_rw_semaphore *); > extern void percpu_down_write(struct percpu_rw_semaphore *); > extern void percpu_up_write(struct percpu_rw_semaphore *); > > +static inline bool percpu_is_write_locked(struct percpu_rw_semaphore *sem) > +{ > + return atomic_read(&sem->block); > +} > + > extern int __percpu_init_rwsem(struct percpu_rw_semaphore *, > const char *, struct lock_class_key *); > > diff --git a/kernel/locking/percpu-rwsem.c b/kernel/locking/percpu-rwsem.c > index 5fe4c5495ba3..213d114fb025 100644 > --- a/kernel/locking/percpu-rwsem.c > +++ b/kernel/locking/percpu-rwsem.c > @@ -192,6 +192,12 @@ EXPORT_SYMBOL_GPL(__percpu_down_read); > __sum; \ > }) > > +bool percpu_is_read_locked(struct percpu_rw_semaphore *sem) > +{ > + return per_cpu_sum(*sem->read_count) != 0; > +} > +EXPORT_SYMBOL_GPL(percpu_is_read_locked); > + > /* > * Return true if the modular sum of the sem->read_count per-CPU variable is > * zero. If this sum is zero, then it is stable due to the fact that if any > -- > 2.37.0.rc0.161.g10f37bed90-goog >
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