Here's v2 of the patchset. It doesn't sound like there's anything terribly controversial here so this version is mostly just some cleanup changes for clarity. Changes in v2: * Rebase on v5.3-rc2 (No changes) * Re-introduce the private pagemap structure and move the p2p-specific elements out of the commond dev_pagemap (per Christoph) * Use flags instead of bool in the whitelist (per Jason) * Only store the mapping type in the xarray (instead of the distance with flags) such that a function can return the mapping method with a switch statement to decide how to map. (per Christoph) * Drop find_parent_pci_dev() on the fast path and rely on the fact that the struct device passed to the mapping functions *must* be a PCI device and convert it directly. (per suggestions from Christoph and Jason) * Collected Christian's Reviewed-by's -- As discussed on the list previously, in order to fully support the whitelist Christian added with the IOMMU, we must ensure that we map any buffer going through the IOMMU with an aprropriate dma_map call. This patchset accomplishes this by cleaning up the output of upstream_bridge_distance() to better indicate the mapping requirements, caching these requirements in an xarray, then looking them up at map time and applying the appropriate mapping method. After this patchset, it's possible to use the NVMe-of P2P support to transfer between devices without a switch on the whitelisted root complexes. A couple Intel device I have tested this on have also been added to the white list. Most of the changes are contained within the p2pdma.c, but there are a few minor touches to other subsystems, mostly to add support to call an unmap function. The final patch in this series demonstrates a possible pci_p2pdma_map_resource() function that I expect Christian will need but does not have any users at this time so I don't intend for it to be considered for merging. This patchset is based on 5.3-rc2 and a git branch is available here: https://github.com/sbates130272/linux-p2pmem/ p2pdma_rc_map_v2 -- Logan Gunthorpe (14): PCI/P2PDMA: Introduce private pagemap structure PCI/P2PDMA: Add the provider's pci_dev to the pci_p2pdma_pagemap struct PCI/P2PDMA: Add constants for not-supported result upstream_bridge_distance() PCI/P2PDMA: Factor out __upstream_bridge_distance() PCI/P2PDMA: Apply host bridge white list for ACS PCI/P2PDMA: Factor out host_bridge_whitelist() PCI/P2PDMA: Add whitelist support for Intel Host Bridges PCI/P2PDMA: Add attrs argument to pci_p2pdma_map_sg() PCI/P2PDMA: Introduce pci_p2pdma_unmap_sg() PCI/P2PDMA: Factor out __pci_p2pdma_map_sg() PCI/P2PDMA: Store mapping method in an xarray PCI/P2PDMA: dma_map P2PDMA map requests that traverse the host bridge PCI/P2PDMA: No longer require no-mmu for host bridge whitelist PCI/P2PDMA: Update documentation for pci_p2pdma_distance_many() drivers/infiniband/core/rw.c | 6 +- drivers/nvme/host/pci.c | 10 +- drivers/pci/p2pdma.c | 361 +++++++++++++++++++++++++---------- include/linux/memremap.h | 1 - include/linux/pci-p2pdma.h | 28 ++- 5 files changed, 296 insertions(+), 110 deletions(-) -- 2.20.1
