[PATCH 00/16] Add new DMA mapping operation for P2PDMA

Logan Gunthorpe
2021-04-08T17:01:47Z

Hi,

This patchset continues my work to to add P2PDMA support to the common
dma map operations. This allows for creating SGLs that have both P2PDMA
and regular pages which is a necessary step to allowing P2PDMA pages in
userspace.

The earlier RFC[1] generated a lot of great feedback and I heard no show
stopping objections. Thus, I've incorporated all the feedback and have
decided to post this as a proper patch series with hopes of eventually
getting it in mainline.

I'm happy to do a few more passes if anyone has any further feedback
or better ideas.

This series is based on v5.12-rc6 and a git branch can be found here:

https://github.com/sbates130272/linux-p2pmem/ p2pdma_map_ops_v1

Thanks,

Logan

[1] https://lore.kernel.org/linux-block/20210311233142.7900-1-logang@deltatee.com/

Changes since the RFC:
* Added comment and fixed up the pci_get_slot patch. (per Bjorn)
* Fixed glaring sg_phys() double offset bug. (per Robin)
* Created a new map operation (dma_map_sg_p2pdma()) with a new calling
convention instead of modifying the calling convention of
dma_map_sg(). (per Robin)
* Integrated the two similar pci_p2pdma_dma_map_type() and
pci_p2pdma_map_type() functions into one (per Ira)
* Reworked some of the logic in the map_sg() implementations into
helpers in the p2pdma code. (per Christoph)
* Dropped a bunch of unnecessary symbol exports (per Christoph)
* Expanded the code in dma_pci_p2pdma_supported() for clarity. (per
Ira and Christoph)
* Finished off using the new dma_map_sg_p2pdma() call in rdma_rw
and removed the old pci_p2pdma_[un]map_sg(). (per Jason)

--

Logan Gunthorpe (16):
PCI/P2PDMA: Pass gfp_mask flags to upstream_bridge_distance_warn()
PCI/P2PDMA: Avoid pci_get_slot() which sleeps
PCI/P2PDMA: Attempt to set map_type if it has not been set
PCI/P2PDMA: Refactor pci_p2pdma_map_type() to take pagmap and device
dma-mapping: Introduce dma_map_sg_p2pdma()
lib/scatterlist: Add flag for indicating P2PDMA segments in an SGL
PCI/P2PDMA: Make pci_p2pdma_map_type() non-static
PCI/P2PDMA: Introduce helpers for dma_map_sg implementations
dma-direct: Support PCI P2PDMA pages in dma-direct map_sg
dma-mapping: Add flags to dma_map_ops to indicate PCI P2PDMA support
iommu/dma: Support PCI P2PDMA pages in dma-iommu map_sg
nvme-pci: Check DMA ops when indicating support for PCI P2PDMA
nvme-pci: Convert to using dma_map_sg_p2pdma for p2pdma pages
nvme-rdma: Ensure dma support when using p2pdma
RDMA/rw: use dma_map_sg_p2pdma()
PCI/P2PDMA: Remove pci_p2pdma_[un]map_sg()

drivers/infiniband/core/rw.c | 50 +++-------
drivers/iommu/dma-iommu.c | 66 ++++++++++--
drivers/nvme/host/core.c | 3 +-
drivers/nvme/host/nvme.h | 2 +-
drivers/nvme/host/pci.c | 39 ++++----
drivers/nvme/target/rdma.c | 3 +-
drivers/pci/Kconfig | 2 +-
drivers/pci/p2pdma.c | 188 +++++++++++++++++++----------------
include/linux/dma-map-ops.h | 3 +
include/linux/dma-mapping.h | 20 ++++
include/linux/pci-p2pdma.h | 53 ++++++----
include/linux/scatterlist.h | 49 ++++++++-
include/rdma/ib_verbs.h | 32 ++++++
kernel/dma/direct.c | 25 ++++-
kernel/dma/mapping.c | 70 +++++++++++--
15 files changed, 416 insertions(+), 189 deletions(-)

base-commit: e49d033bddf5b565044e2abe4241353959bc9120
--
2.20.1