On 2021-03-16 1:58 a.m., Christoph Hellwig wrote: > On Fri, Mar 12, 2021 at 11:27:46AM -0700, Logan Gunthorpe wrote: >> So then we reject the patches that make that change. Seems like an odd >> argument to say that we can't do something that won't cause problems >> because someone might use it as an example and do something that will >> cause problems. Reject the change that causes the problem. > > No, the problem is a mess of calling conventions. A calling convention > returning 0 for error, positive values for success is fine. One returning > a negative errno for error and positive values for success is fine a well. > One returning 0 for the usual errors and negativ errnos for an unusual > corner case is just a complete mess. Fair enough. I can try implementing a dma_map_sg_p2p() roughly as Robin suggested that has a more reasonable calling convention. Most of your other feedback seems easy enough so I'll address it in a future series. Thanks, Logan