Hi, This is the latest P2PDMA userspace patch set. This version includes some cleanup from feedback of the last posting[1]. This patch set enables userspace P2PDMA by allowing userspace to mmap() allocated chunks of the CMB. The resulting VMA can be passed only to O_DIRECT IO on NVMe backed files or block devices. A flag is added to GUP() in Patch 1, then Patches 2 through 6 wire this flag up based on whether the block queue indicates P2PDMA support. Patches 7 creates the sysfs resource that can hand out the VMAs and Patch 8 adds brief documentation for the new interface. Feedback welcome. This series is based on v6.0-rc6. A git branch is available here: https://github.com/sbates130272/linux-p2pmem/ p2pdma_user_cmb_v10 Thanks, Logan [1] https://lkml.kernel.org/r/20220825152425.6296-1-logang@xxxxxxxxxxxx -- Changes since v8: - Rebased onto v6.0-rc6 - Reworked iov iter changes to reuse the code better and name them without the _flags() prefix (per Christoph) - Renamed a number of flags variables to gup_flags (per John) - Minor fixups to the last documentation patch (from Greg and John) Changes since v7: - Rebased onto v6.0-rc2, included reworking the iov_iter patch due to changes there - Drop the char device mmap implementation in favour of a sysfs based interface. (per Christoph) Changes since v6: - Rebase onto v5.19-rc1 - Rework how the pages are stored in the VMA per Jason's suggestion Changes since v5: - Rebased onto v5.18-rc1 which includes Christophs cleanup to free_zone_device_page() (similar to Ralph's patch). - Fix bug with concurrent first calls to pci_p2pdma_vma_fault() that caused a double allocation and lost p2p memory. Noticed by Andrew Maier. - Collected a Reviewed-by tag from Chaitanya. - Numerous minor fixes to commit messages -- Logan Gunthorpe (8): mm: introduce FOLL_PCI_P2PDMA to gate getting PCI P2PDMA pages iov_iter: introduce iov_iter_get_pages_[alloc_]flags() block: add check when merging zone device pages lib/scatterlist: add check when merging zone device pages block: set FOLL_PCI_P2PDMA in __bio_iov_iter_get_pages() block: set FOLL_PCI_P2PDMA in bio_map_user_iov() PCI/P2PDMA: Allow userspace VMA allocations through sysfs ABI: sysfs-bus-pci: add documentation for p2pmem allocate Documentation/ABI/testing/sysfs-bus-pci | 10 ++ block/bio.c | 11 ++- block/blk-map.c | 7 +- drivers/pci/p2pdma.c | 124 ++++++++++++++++++++++++ include/linux/mm.h | 1 + include/linux/mmzone.h | 24 +++++ include/linux/uio.h | 6 ++ lib/iov_iter.c | 32 ++++-- lib/scatterlist.c | 25 +++-- mm/gup.c | 22 ++++- 10 files changed, 240 insertions(+), 22 deletions(-) base-commit: 521a547ced6477c54b4b0cc206000406c221b4d6 -- 2.30.2
