Hi, This is the latest P2PDMA userspace patch set. This version includes some cleanup from feedback from 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 v6.1-rc1. A git branch is available here: https://github.com/sbates130272/linux-p2pmem/ p2pdma_user_cmb_v11 Thanks, Logan [1] https://lkml.kernel.org/r/20220922163926.7077-1-logang@xxxxxxxxxxxx -- Changes in v11: - Rebased onto v6.1-rc1, fixed minor conflict in bio_map_user_iov - The GUP test was moved to try_grab_page() and try_grab_folio(). This ought to be a bit more future proof. It required adding a new cleanup patch to return a proper error code from try_grab_page(). (Per Jason) Changes in v10: - 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 in v9: - 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) (v8 only included the first half of the series and was merged for v6.0) Changes in v8: - Rebase onto v5.19-rc1 - Rework how the pages are stored in the VMA per Jason's suggestion Changes in v7: - 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 (9): mm: allow multiple error returns in try_grab_page() 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 | 12 ++- drivers/pci/p2pdma.c | 124 ++++++++++++++++++++++++ include/linux/mm.h | 3 +- include/linux/mmzone.h | 24 +++++ include/linux/uio.h | 6 ++ lib/iov_iter.c | 32 ++++-- lib/scatterlist.c | 25 +++-- mm/gup.c | 45 ++++++--- mm/huge_memory.c | 19 ++-- mm/hugetlb.c | 23 +++-- 12 files changed, 280 insertions(+), 54 deletions(-) base-commit: 9abf2313adc1ca1b6180c508c25f22f9395cc780 -- 2.30.2
