On 06/02/14 12:56, Zoltan Kiss wrote:
> The grant mapping API does m2p_override unnecessarily: only gntdev needs it,
> for blkback and future netback patches it just cause a lock contention, as
> those pages never go to userspace. Therefore this series does the following:
> - the original functions were renamed to __gnttab_[un]map_refs, with a new
> parameter m2p_override
> - based on m2p_override either they follow the original behaviour, or just set
> the private flag and call set_phys_to_machine
> - gnttab_[un]map_refs are now a wrapper to call __gnttab_[un]map_refs with
> m2p_override false
> - a new function gnttab_[un]map_refs_userspace provides the old behaviour
> - it cuts out common parts from m2p_*_override functions to
> *_foreign_p2m_mapping functions
>
> It also removes a stray space from page.h and change ret to 0 if
> XENFEAT_auto_translated_physmap, as that is the only possible return value
> there.
>
> v2:
Please put this version information after the '---' marker. It doesn't
need to end up in the commit message.
> @@ -955,10 +957,12 @@ int gnttab_map_refs(struct gnttab_map_grant_ref
> *map_ops,
> set_phys_to_machine(map_ops[i].host_addr >> PAGE_SHIFT,
> map_ops[i].dev_bus_addr >> PAGE_SHIFT);
> }
> - return ret;
> + return 0;
> }
>
> - if (!in_interrupt() && paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> + if (m2p_override &&
> + !in_interrupt() &&
> + paravirt_get_lazy_mode() == PARAVIRT_LAZY_NONE) {
> arch_enter_lazy_mmu_mode();
> lazy = true;
> }
I think this block and the loop should be in an arch-specific function
(e.g., set_foreign_p2m_mappings(), but I would like to hear Stefano's
opinion.
Similarly for clear_foreign_p2m_mappings().
David
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