Messages in this thread | | | Date | Thu, 07 Apr 2005 02:48:59 +1000 | From | Nick Piggin <> | Subject | Re: return value of ptep_get_and_clear |
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Kumar Gala wrote: > ptep_get_and_clear has a signature that looks something like: > > static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned > long addr, > pte_t *ptep) > > It appears that its suppose to return the pte_t pointed to by ptep > before its modified. Why do we bother doing this? The caller seems > perfectly able to dereference ptep and hold on to it. Am I missing > something here? >
You need to be able to *atomically* clear the pte and retrieve the old value.
Nick
-- SUSE Labs, Novell Inc.
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