linux/kernel/dma, branch v6.18

Merge tag 'dma-mapping-6.18-2025-11-27' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux

2025-11-28T01:29:15Z

Pull dma-mapping fixes from Marek Szyprowski: "Two last minute fixes for the recently modified DMA API infrastructure: - proper handling of DMA_ATTR_MMIO in dma_iova_unlink() function (me) - regression fix for the code refactoring related to P2PDMA (Pranjal Shrivastava)" * tag 'dma-mapping-6.18-2025-11-27' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: dma-direct: Fix missing sg_dma_len assignment in P2PDMA bus mappings iommu/dma: add missing support for DMA_ATTR_MMIO for dma_iova_unlink()

dma-direct: Fix missing sg_dma_len assignment in P2PDMA bus mappings

2025-11-26T20:47:13Z

Prior to commit a25e7962db0d7 ("PCI/P2PDMA: Refactor the p2pdma mapping helpers"), P2P segments were mapped using the pci_p2pdma_map_segment() helper. This helper was responsible for populating sg->dma_address, marking the bus address, and also setting sg_dma_len(sg). The refactor[1] removed this helper and moved the mapping logic directly into the callers. While iommu_dma_map_sg() was correctly updated to set the length in the new flow, it was missed in dma_direct_map_sg(). Thus, in dma_direct_map_sg(), the PCI_P2PDMA_MAP_BUS_ADDR case sets the dma_address and marks the segment, but immediately executes 'continue', which causes the loop to skip the standard assignment logic at the end: sg_dma_len(sg) = sg->length; As a result, when CONFIG_NEED_SG_DMA_LENGTH is enabled, the dma_length field remains uninitialized (zero) for P2P bus address mappings. This breaks upper-layer drivers (for e.g. RDMA/IB) that rely on sg_dma_len() to determine the transfer size. Fix this by explicitly setting the DMA length in the PCI_P2PDMA_MAP_BUS_ADDR case before continuing to the next scatterlist entry. Fixes: a25e7962db0d7 ("PCI/P2PDMA: Refactor the p2pdma mapping helpers") Reported-by: Jacob Moroni Signed-off-by: Pranjal Shrivastava [1] https://lore.kernel.org/all/ac14a0e94355bf898de65d023ccf8a2ad22a3ece.1746424934.git.leon@kernel.org/ Reviewed-by: Logan Gunthorpe Reviewed-by: Leon Romanovsky Reviewed-by: Shivaji Kant Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/20251126114112.3694469-1-praan@google.com

dma-debug: don't report false positives with DMA_BOUNCE_UNALIGNED_KMALLOC

2025-10-15T20:24:33Z

Commit 370645f41e6e ("dma-mapping: force bouncing if the kmalloc() size is not cache-line-aligned") introduced DMA_BOUNCE_UNALIGNED_KMALLOC feature and permitted architecture specific code configure kmalloc slabs with sizes smaller than the value of dma_get_cache_alignment(). When that feature is enabled, the physical address of some small kmalloc()-ed buffers might be not aligned to the CPU cachelines, thus not really suitable for typical DMA. To properly handle that case a SWIOTLB buffer bouncing is used, so no CPU cache corruption occurs. When that happens, there is no point reporting a false-positive DMA-API warning that the buffer is not properly aligned, as this is not a client driver fault. [m.szyprowski@samsung.com: replace is_swiotlb_allocated() with is_swiotlb_active(), per Catalin] Link: https://lkml.kernel.org/r/20251010173009.3916215-1-m.szyprowski@samsung.com Link: https://lkml.kernel.org/r/20251009141508.2342138-1-m.szyprowski@samsung.com Fixes: 370645f41e6e ("dma-mapping: force bouncing if the kmalloc() size is not cache-line-aligned") Signed-off-by: Marek Szyprowski Reviewed-by: Catalin Marinas Cc: Christoph Hellwig Cc: Inki Dae Cc: Robin Murohy Cc: "Isaac J. Manjarres" Cc: Signed-off-by: Andrew Morton

Merge tag 'dma-mapping-6.18-2025-09-30' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux

2025-10-04T00:41:12Z

Pull dma-mapping updates from Marek Szyprowski: - Refactoring of DMA mapping API to physical addresses as the primary interface instead of page+offset parameters This gets much closer to Matthew Wilcox's long term wish for struct-pageless IO to cacheable DRAM and is supporting memdesc project which seeks to substantially transform how struct page works. An advantage of this approach is the possibility of introducing DMA_ATTR_MMIO, which covers existing 'dma_map_resource' flow in the common paths, what in turn lets to use recently introduced dma_iova_link() API to map PCI P2P MMIO without creating struct page Developped by Leon Romanovsky and Jason Gunthorpe - Minor clean-up by Petr Tesarik and Qianfeng Rong * tag 'dma-mapping-6.18-2025-09-30' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: kmsan: fix missed kmsan_handle_dma() signature conversion mm/hmm: properly take MMIO path mm/hmm: migrate to physical address-based DMA mapping API dma-mapping: export new dma_*map_phys() interface xen: swiotlb: Open code map_resource callback dma-mapping: implement DMA_ATTR_MMIO for dma_(un)map_page_attrs() kmsan: convert kmsan_handle_dma to use physical addresses dma-mapping: convert dma_direct_*map_page to be phys_addr_t based iommu/dma: implement DMA_ATTR_MMIO for iommu_dma_(un)map_phys() iommu/dma: rename iommu_dma_*map_page to iommu_dma_*map_phys dma-mapping: rename trace_dma_*map_page to trace_dma_*map_phys dma-debug: refactor to use physical addresses for page mapping iommu/dma: implement DMA_ATTR_MMIO for dma_iova_link(). dma-mapping: introduce new DMA attribute to indicate MMIO memory swiotlb: Remove redundant __GFP_NOWARN dma-direct: clean up the logic in __dma_direct_alloc_pages()

Merge tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-10-03T01:18:33Z

Pull MM updates from Andrew Morton: - "mm, swap: improve cluster scan strategy" from Kairui Song improves performance and reduces the failure rate of swap cluster allocation - "support large align and nid in Rust allocators" from Vitaly Wool permits Rust allocators to set NUMA node and large alignment when perforning slub and vmalloc reallocs - "mm/damon/vaddr: support stat-purpose DAMOS" from Yueyang Pan extend DAMOS_STAT's handling of the DAMON operations sets for virtual address spaces for ops-level DAMOS filters - "execute PROCMAP_QUERY ioctl under per-vma lock" from Suren Baghdasaryan reduces mmap_lock contention during reads of /proc/pid/maps - "mm/mincore: minor clean up for swap cache checking" from Kairui Song performs some cleanup in the swap code - "mm: vm_normal_page*() improvements" from David Hildenbrand provides code cleanup in the pagemap code - "add persistent huge zero folio support" from Pankaj Raghav provides a block layer speedup by optionalls making the huge_zero_pagepersistent, instead of releasing it when its refcount falls to zero - "kho: fixes and cleanups" from Mike Rapoport adds a few touchups to the recently added Kexec Handover feature - "mm: make mm->flags a bitmap and 64-bit on all arches" from Lorenzo Stoakes turns mm_struct.flags into a bitmap. To end the constant struggle with space shortage on 32-bit conflicting with 64-bit's needs - "mm/swapfile.c and swap.h cleanup" from Chris Li cleans up some swap code - "selftests/mm: Fix false positives and skip unsupported tests" from Donet Tom fixes a few things in our selftests code - "prctl: extend PR_SET_THP_DISABLE to only provide THPs when advised" from David Hildenbrand "allows individual processes to opt-out of THP=always into THP=madvise, without affecting other workloads on the system". It's a long story - the [1/N] changelog spells out the considerations - "Add and use memdesc_flags_t" from Matthew Wilcox gets us started on the memdesc project. Please see https://kernelnewbies.org/MatthewWilcox/Memdescs and https://blogs.oracle.com/linux/post/introducing-memdesc - "Tiny optimization for large read operations" from Chi Zhiling improves the efficiency of the pagecache read path - "Better split_huge_page_test result check" from Zi Yan improves our folio splitting selftest code - "test that rmap behaves as expected" from Wei Yang adds some rmap selftests - "remove write_cache_pages()" from Christoph Hellwig removes that function and converts its two remaining callers - "selftests/mm: uffd-stress fixes" from Dev Jain fixes some UFFD selftests issues - "introduce kernel file mapped folios" from Boris Burkov introduces the concept of "kernel file pages". Using these permits btrfs to account its metadata pages to the root cgroup, rather than to the cgroups of random inappropriate tasks - "mm/pageblock: improve readability of some pageblock handling" from Wei Yang provides some readability improvements to the page allocator code - "mm/damon: support ARM32 with LPAE" from SeongJae Park teaches DAMON to understand arm32 highmem - "tools: testing: Use existing atomic.h for vma/maple tests" from Brendan Jackman performs some code cleanups and deduplication under tools/testing/ - "maple_tree: Fix testing for 32bit compiles" from Liam Howlett fixes a couple of 32-bit issues in tools/testing/radix-tree.c - "kasan: unify kasan_enabled() and remove arch-specific implementations" from Sabyrzhan Tasbolatov moves KASAN arch-specific initialization code into a common arch-neutral implementation - "mm: remove zpool" from Johannes Weiner removes zspool - an indirection layer which now only redirects to a single thing (zsmalloc) - "mm: task_stack: Stack handling cleanups" from Pasha Tatashin makes a couple of cleanups in the fork code - "mm: remove nth_page()" from David Hildenbrand makes rather a lot of adjustments at various nth_page() callsites, eventually permitting the removal of that undesirable helper function - "introduce kasan.write_only option in hw-tags" from Yeoreum Yun creates a KASAN read-only mode for ARM, using that architecture's memory tagging feature. It is felt that a read-only mode KASAN is suitable for use in production systems rather than debug-only - "mm: hugetlb: cleanup hugetlb folio allocation" from Kefeng Wang does some tidying in the hugetlb folio allocation code - "mm: establish const-correctness for pointer parameters" from Max Kellermann makes quite a number of the MM API functions more accurate about the constness of their arguments. This was getting in the way of subsystems (in this case CEPH) when they attempt to improving their own const/non-const accuracy - "Cleanup free_pages() misuse" from Vishal Moola fixes a number of code sites which were confused over when to use free_pages() vs __free_pages() - "Add Rust abstraction for Maple Trees" from Alice Ryhl makes the mapletree code accessible to Rust. Required by nouveau and by its forthcoming successor: the new Rust Nova driver - "selftests/mm: split_huge_page_test: split_pte_mapped_thp improvements" from David Hildenbrand adds a fix and some cleanups to the thp selftesting code - "mm, swap: introduce swap table as swap cache (phase I)" from Chris Li and Kairui Song is the first step along the path to implementing "swap tables" - a new approach to swap allocation and state tracking which is expected to yield speed and space improvements. This patchset itself yields a 5-20% performance benefit in some situations - "Some ptdesc cleanups" from Matthew Wilcox utilizes the new memdesc layer to clean up the ptdesc code a little - "Fix va_high_addr_switch.sh test failure" from Chunyu Hu fixes some issues in our 5-level pagetable selftesting code - "Minor fixes for memory allocation profiling" from Suren Baghdasaryan addresses a couple of minor issues in relatively new memory allocation profiling feature - "Small cleanups" from Matthew Wilcox has a few cleanups in preparation for more memdesc work - "mm/damon: add addr_unit for DAMON_LRU_SORT and DAMON_RECLAIM" from Quanmin Yan makes some changes to DAMON in furtherance of supporting arm highmem - "selftests/mm: Add -Wunreachable-code and fix warnings" from Muhammad Anjum adds that compiler check to selftests code and fixes the fallout, by removing dead code - "Improvements to Victim Process Thawing and OOM Reaper Traversal Order" from zhongjinji makes a number of improvements in the OOM killer: mainly thawing a more appropriate group of victim threads so they can release resources - "mm/damon: misc fixups and improvements for 6.18" from SeongJae Park is a bunch of small and unrelated fixups for DAMON - "mm/damon: define and use DAMON initialization check function" from SeongJae Park implement reliability and maintainability improvements to a recently-added bug fix - "mm/damon/stat: expose auto-tuned intervals and non-idle ages" from SeongJae Park provides additional transparency to userspace clients of the DAMON_STAT information - "Expand scope of khugepaged anonymous collapse" from Dev Jain removes some constraints on khubepaged's collapsing of anon VMAs. It also increases the success rate of MADV_COLLAPSE against an anon vma - "mm: do not assume file == vma->vm_file in compat_vma_mmap_prepare()" from Lorenzo Stoakes moves us further towards removal of file_operations.mmap(). This patchset concentrates upon clearing up the treatment of stacked filesystems - "mm: Improve mlock tracking for large folios" from Kiryl Shutsemau provides some fixes and improvements to mlock's tracking of large folios. /proc/meminfo's "Mlocked" field became more accurate - "mm/ksm: Fix incorrect accounting of KSM counters during fork" from Donet Tom fixes several user-visible KSM stats inaccuracies across forks and adds selftest code to verify these counters - "mm_slot: fix the usage of mm_slot_entry" from Wei Yang addresses some potential but presently benign issues in KSM's mm_slot handling * tag 'mm-stable-2025-10-01-19-00' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (372 commits) mm: swap: check for stable address space before operating on the VMA mm: convert folio_page() back to a macro mm/khugepaged: use start_addr/addr for improved readability hugetlbfs: skip VMAs without shareable locks in hugetlb_vmdelete_list alloc_tag: fix boot failure due to NULL pointer dereference mm: silence data-race in update_hiwater_rss mm/memory-failure: don't select MEMORY_ISOLATION mm/khugepaged: remove definition of struct khugepaged_mm_slot mm/ksm: get mm_slot by mm_slot_entry() when slot is !NULL hugetlb: increase number of reserving hugepages via cmdline selftests/mm: add fork inheritance test for ksm_merging_pages counter mm/ksm: fix incorrect KSM counter handling in mm_struct during fork drivers/base/node: fix double free in register_one_node() mm: remove PMD alignment constraint in execmem_vmalloc() mm/memory_hotplug: fix typo 'esecially' -> 'especially' mm/rmap: improve mlock tracking for large folios mm/filemap: map entire large folio faultaround mm/fault: try to map the entire file folio in finish_fault() mm/rmap: mlock large folios in try_to_unmap_one() mm/rmap: fix a mlock race condition in folio_referenced_one() ...

dma-remap: drop nth_page() in dma_common_contiguous_remap()

2025-09-21T21:22:06Z

dma_common_contiguous_remap() is used to remap an "allocated contiguous region". Within a single allocation, there is no need to use nth_page() anymore. Neither the buddy, nor hugetlb, nor CMA will hand out problematic page ranges. Link: https://lkml.kernel.org/r/20250901150359.867252-24-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Marek Szyprowski Reviewed-by: Lorenzo Stoakes Cc: Robin Murphy Signed-off-by: Andrew Morton

dma-mapping: export new dma_*map_phys() interface

2025-09-11T22:18:21Z

Introduce new DMA mapping functions dma_map_phys() and dma_unmap_phys() that operate directly on physical addresses instead of page+offset parameters. This provides a more efficient interface for drivers that already have physical addresses available. The new functions are implemented as the primary mapping layer, with the existing dma_map_page_attrs()/dma_map_resource() and dma_unmap_page_attrs()/dma_unmap_resource() functions converted to simple wrappers around the phys-based implementations. In case dma_map_page_attrs(), the struct page is converted to physical address with help of page_to_phys() function and dma_map_resource() provides physical address as is together with addition of DMA_ATTR_MMIO attribute. The old page-based API is preserved in mapping.c to ensure that existing code won't be affected by changing EXPORT_SYMBOL to EXPORT_SYMBOL_GPL variant for dma_*map_phys(). Reviewed-by: Jason Gunthorpe Reviewed-by: Keith Busch Signed-off-by: Leon Romanovsky Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/54cc52af91777906bbe4a386113437ba0bcfba9c.1757423202.git.leonro@nvidia.com

dma-mapping: implement DMA_ATTR_MMIO for dma_(un)map_page_attrs()

2025-09-11T22:18:20Z

Make dma_map_page_attrs() and dma_map_page_attrs() respect DMA_ATTR_MMIO. DMA_ATR_MMIO makes the functions behave the same as dma_(un)map_resource(): - No swiotlb is possible - Legacy dma_ops arches use ops->map_resource() - No kmsan - No arch_dma_map_phys_direct() The prior patches have made the internal functions called here support DMA_ATTR_MMIO. This is also preparation for turning dma_map_resource() into an inline calling dma_map_phys(DMA_ATTR_MMIO) to consolidate the flows. Reviewed-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/3660e2c78ea409d6c483a215858fb3af52cd0ed3.1757423202.git.leonro@nvidia.com

kmsan: convert kmsan_handle_dma to use physical addresses

2025-09-11T22:18:20Z

Convert the KMSAN DMA handling function from page-based to physical address-based interface. The refactoring renames kmsan_handle_dma() parameters from accepting (struct page *page, size_t offset, size_t size) to (phys_addr_t phys, size_t size). The existing semantics where callers are expected to provide only kmap memory is continued here. Reviewed-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/3557cbaf66e935bc794f37d2b891ef75cbf2c80c.1757423202.git.leonro@nvidia.com

dma-mapping: convert dma_direct_*map_page to be phys_addr_t based

2025-09-11T22:18:20Z

Convert the DMA direct mapping functions to accept physical addresses directly instead of page+offset parameters. The functions were already operating on physical addresses internally, so this change eliminates the redundant page-to-physical conversion at the API boundary. The functions dma_direct_map_page() and dma_direct_unmap_page() are renamed to dma_direct_map_phys() and dma_direct_unmap_phys() respectively, with their calling convention changed from (struct page *page, unsigned long offset) to (phys_addr_t phys). Architecture-specific functions arch_dma_map_page_direct() and arch_dma_unmap_page_direct() are similarly renamed to arch_dma_map_phys_direct() and arch_dma_unmap_phys_direct(). The is_pci_p2pdma_page() checks are replaced with DMA_ATTR_MMIO checks to allow integration with dma_direct_map_resource and dma_direct_map_phys() is extended to support MMIO path either. Reviewed-by: Jason Gunthorpe Signed-off-by: Leon Romanovsky Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/bb15a22f76dc2e26683333ff54e789606cfbfcf0.1757423202.git.leonro@nvidia.com