Re: [Xen-devel] [PATCH v5 5/7] VT-d: Refactor iommu_ops .map_page() and unmap_page()

["Xu, Quan" <quan.xu@xxxxxxxxx>]

> On February 25, 2016 8:24pm, <JBeulich@xxxxxxxx> wrote:
> >>> On 25.02.16 at 13:14, <quan.xu@xxxxxxxxx> wrote:
> > On February 25, 2016 4:59pm, <JBeulich@xxxxxxxx> wrote:
> >> I'd
> >> really suggest investigating alternatives. One that comes to mind
> >> would be to move acquiring/releasing pcidevs_lock into a helper
> >> function, and setting a per-CPU flag indicating ownership.
> >
> > To me, this might be fine.
> > Does Per-CPU flag refer to this_cpu(iommu_dont_flush_iotlb) or variant?
> 
> Yes. But I'd prefer ...
> 
> >> However, the same effect could be achieved by making the lock a
> >> recursive one, which would then seem to more conventional approach
> >> (but requiring as much code to be touched).
> >> Both approached would eliminate the need to pass down "locked"
> >> flags.
> 
> ... this one (the more that the other won't mean less changes).
> 

Agreed, I am going to make the lock a recursive one. I will summarize the 
modification and send it out.

-Quan

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