Re: [PATCH 02/11] xfs: start creating infrastructure for health monitoring

["Darrick J. Wong" <djwong@kernel.org>]

On Fri, Feb 06, 2026 at 02:07:56PM +0100, Pankaj Raghav (Samsung) wrote:
> > +static DEFINE_SPINLOCK(xfs_healthmon_lock);
> > +
> > +/* Grab a reference to the healthmon object for a given mount, if any. */
> > +static struct xfs_healthmon *
> > +xfs_healthmon_get(
> > +	struct xfs_mount		*mp)
> > +{
> > +	struct xfs_healthmon		*hm;
> > +
> > +	rcu_read_lock();
> > +	hm = mp->m_healthmon;
> 
> Nit: Should we do a READ_ONCE(mp->m_healthmon) here to avoid any
> compiler tricks that can result in an undefined behaviour? I am not sure
> if I am being paranoid here.

Compiler tricks?  We've taken the rcu read lock, which adds an
optimization barrier so that the mp->m_healthmon access can't be
reordered before the rcu_read_lock.  I'm not sure if that answers your
question.

<confused>

--D

> > +	if (hm && !refcount_inc_not_zero(&hm->ref))
> > +		hm = NULL;
> > +	rcu_read_unlock();
> > +
> > +	return hm;
> > +}
> > +
> > +/*
> -- 
> Pankaj
>