On 27/04/17 12:53 AM, Christoph Hellwig wrote: > I think you'll need to follow the existing kmap semantics and never > fail the iomem version either. Otherwise you'll have a special case > that's almost never used that has a different error path. > > Again, wrong way. Suddenly making things fail for your special case > that normally don't fail is a receipe for bugs. I don't disagree but these restrictions make the problem impossible to solve? If there is iomem behind a page in an SGL and someone tries to map it, we either have to fail or we break iomem safety which was your original concern. Logan
