Messages in this thread | | | Date | Tue, 15 May 2018 11:02:19 -0700 | From | Matthew Wilcox <> | Subject | Re: [PATCH v3 2/2] locking/percpu-rwsem: Annotate rwsem ownership transfer by setting RWSEM_OWNER_UNKNOWN |
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On Tue, May 15, 2018 at 07:58:05PM +0200, Peter Zijlstra wrote: > 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.
I'd rather change the definition to be ((struct task_struct *)2) otherwise this is both reader-owned and anonymously-owned which doesn't make much sense.
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