Messages in this thread | | | Date | Mon, 20 Aug 2018 02:40:12 -0600 | From | "Jan Beulich" <> | Subject | Re: [Xen-devel] [PATCH 2/2] x86/pae: use 64 bit atomic xchg function in native_ptep_get_and_clear |
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>>> On 20.08.18 at 07:14, <jgross@suse.com> wrote: > @@ -148,14 +150,14 @@ static inline void pud_clear(pud_t *pudp) > #ifdef CONFIG_SMP > static inline pte_t native_ptep_get_and_clear(pte_t *ptep) > { > - pte_t res; > + union { > + pte_t pte; > + long long val; > + } res;
Why the union? pte_t already is one, with the pte field being what you're after ...
> - /* xchg acts as a barrier before the setting of the high bits */ > - res.pte_low = xchg(&ptep->pte_low, 0); > - res.pte_high = ptep->pte_high; > - ptep->pte_high = 0; > + res.val = arch_atomic64_xchg((atomic64_t *)ptep, 0);
... here.
Jan
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