Re: [PATCH v3 02/10] swiotlb: Factor out slot allocation and free

[Christoph Hellwig]

On Tue, Apr 23, 2019 at 03:32:16PM +0800, Lu Baolu wrote:
> When we add the bounce buffer between IOVA and physical buffer, the
> bounced buffer must starts from the same offset in a page, otherwise,
> IOMMU can't work here.

Why?  Even with the odd hardware descriptors typical in Intel land that
only allow offsets in the first page, not the following ones, having
a zero offset where we previously had one should be fine.