On Mon, May 14, 2018 at 10:31 PM, Waiman Long <longman@xxxxxxxxxx> wrote: > The percpu_rwsem_release() is called when the ownership of the embedded > rwsem is to be transferred to another task. The new owner, however, may > take a while to get the ownership of the lock via percpu_rwsem_acquire(). > During that period, the rwsem is now marked as writer-owned with no > optimistic spinning. > Waiman, Thanks for the fix. I will test it soon. For this commit message I suggest that you add parts of the reproducer found here: https://marc.info/?l=linux-fsdevel&m=152622016219975&w=2 Thanks, Amir. > Signed-off-by: Waiman Long <longman@xxxxxxxxxx> > --- > include/linux/percpu-rwsem.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h > index b1f37a8..dd37102 100644 > --- a/include/linux/percpu-rwsem.h > +++ b/include/linux/percpu-rwsem.h > @@ -131,16 +131,16 @@ static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem, > bool read, unsigned long ip) > { > lock_release(&sem->rw_sem.dep_map, 1, ip); > -#ifdef CONFIG_RWSEM_SPIN_ON_OWNER > if (!read) > - sem->rw_sem.owner = NULL; > -#endif > + rwsem_set_writer_owned_nospin(&sem->rw_sem); > } > > static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem, > bool read, unsigned long ip) > { > lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip); > + if (!read) > + rwsem_set_writer_owned(&sem->rw_sem, current); > } > > #endif > -- > 1.8.3.1 >
