Messages in this thread | | | From | Amir Goldstein <> | Date | Tue, 15 May 2018 21:05:34 +0300 | 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 9:02 PM, Waiman Long <longman@redhat.com> wrote: > On 05/15/2018 01:58 PM, 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 am just trying not to expose internal working of rwsem, but I can > document that one of the bits is the real deal without specifying which one. >
BUILD_BUG_ON(!rwsem_has_anonymous_owner(RWSEM_OWNER_UNKNOWN)) inside rwsem.c and comment above to explain it.
Thanks, Amir.
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