Re: [PATCH v3 2/2] locking/percpu-rwsem: Annotate rwsem ownership transfer by setting RWSEM_OWNER_UNKNOWN

[Peter Zijlstra]

On Tue, May 15, 2018 at 01:38:04PM -0400, Waiman Long wrote:
> +/*
> + * Owner value to indicate the rwsem's owner is not currently known.
> + */
> +#define RWSEM_OWNER_UNKNOWN	((struct task_struct *)-1)

It might be nice to comment that this works and relies on having that
ANON_OWNER bit set.