On Tue, 2017-04-18 at 10:27 -0700, Dan Williams wrote: > > FWIW, RDMA probably wouldn't want to use a p2mem device either, we > > already have APIs that map BAR memory to user space, and would like to > > keep using them. A 'enable P2P for bar' helper function sounds better > > to me. > > ...and I think it's not a helper function as much as asking the bus > provider "can these two device dma to each other". The "helper" is the > dma api redirecting through a software-iommu that handles bus address > translation differently than it would handle host memory dma mapping. Do we even need tat function ? The dma_ops have a dma_supported() call... If we have those override ops built into the "dma_target" object, then these things can make that decision knowing both the source and target device. Cheers, Ben.
