Hi Ohad,

On Mon, Oct 10, 2011 at 01:02:46PM -0400, Ohad Ben-Cohen wrote:

On Mon, Oct 10, 2011 at 5:36 PM, Roedel, Joerg [off-list ref] wrote:

quoted

Yes, somthing like that. Probably the iommu_ops->unmap function should
be turned into a unmap_page function call which only takes an iova and
no size parameter. The iommu-driver unmaps the page pointing to that
iova and returns the size of the page unmapped. This still allows the
simple implementation for the unmap-call.

Yes, exactly. It will take some time to migrate all drivers (today we
have 4 drivers, each of which is implementing a slightly different
->unmap() semantics), but at least let's not accept any new driver
that doesn't adhere to this, otherwise it's going to be even harder
for the API to evolve.

Agreed. We should change the existing drivers one-by-one.

quoted

We don't need to really enforce the calls to be symetric. But we can
define that we only give the guarantee about what will be unmapped
when the calls are symetric.

Sounds good to me. I'll add this to the kernel doc patch (which I'll
submit after this patch set materializes), and when/if we move to
symmetric only, we will update it.

Great. So if no one disagrees with this direction (this means all the
other people on Cc :) ) it is the way to.

	Joerg

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