On Wed, Sep 06, 2023 at 10:07:24AM -0700, Darrick J. Wong wrote:
> On Wed, Sep 06, 2023 at 05:00:14PM +0100, Matthew Wilcox wrote:
> > +++ b/fs/xfs/xfs_inode.c
> > @@ -361,7 +361,7 @@ xfs_isilocked(
> > {
> > if (lock_flags & (XFS_ILOCK_EXCL|XFS_ILOCK_SHARED)) {
> > if (!(lock_flags & XFS_ILOCK_SHARED))
> > - return !!ip->i_lock.mr_writer;
> > + return rwsem_is_write_locked(&ip->i_lock.mr_lock);
>
> You'd be better off converting this to:
>
> return __xfs_rwsem_islocked(&ip->i_lock.mr_lock,
> (lock_flags & XFS_ILOCK_SHARED));
>
> And then fixing __xfs_rwsem_islocked to do:
>
> static inline bool
> __xfs_rwsem_islocked(
> struct rw_semaphore *rwsem,
> bool shared)
> {
> if (!debug_locks) {
> if (!shared)
> return rwsem_is_write_locked(rwsem);
> return rwsem_is_locked(rwsem);
> }
>
> ...
> }
Thanks.
> > +++ b/include/linux/rwsem.h
> > @@ -72,6 +72,11 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
> > return atomic_long_read(&sem->count) != 0;
> > }
> >
> > +static inline int rwsem_is_write_locked(struct rw_semaphore *sem)
> > +{
> > + return atomic_long_read(&sem->count) & 1;
>
>
> atomic_long_read(&sem->count) & RWSEM_WRITER_LOCKED ?
Then this would either have to be in rwsem.c or we'd have to move the
definition of RWSEM_WRITER_LOCKED to rwsem.h. All three options are
kind of bad. I think I hate the bare '1' least.
