kernel/git/stable/linux.git/mm/cma.c, branch master

mm/cma: remove stray newline from auto-generated CMA area name

2026-08-25T01:43:16+00:00

When no name is supplied, cma_new_area() generates names with format "cma%d\n", introducing an unintended newline character ('\n') in the CMA name. Most CMA regions are created with explicit names, so this path is seldom hit. The newline only creates cosmetic noise in debug logs, traces and debugfs with no functional impact. Link: https://lore.kernel.org/20260810093215.91419-1-hongfu.li@linux.dev Signed-off-by: Hongfu Li Acked-by: David Hildenbrand (Arm) Reviewed-by: Lorenzo Stoakes (ARM) Reviewed-by: SJ Park Reviewed-by: Anshuman Khandual Cc: Liam R. Howlett Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: split out mm_init and memblock declarations from internal.h

2026-08-05T02:18:45+00:00

Patch series "mm: split a couple of headers from internal.h", v2. mm/internal.h becomes more and more bloated. Split declarations related to mm_init, memblock, vmalloc and sparse into new headers. This patch (of 3): mm/internal.h becomes more and more bloated. Move declarations for related to mm/mm_init.c and mm/memblock.c to a new mm/mm_init.h header. No functional changes. [rppt@kernel.org: split stubfs from internal.h to mm_init.h] Link: https://lore.kernel.org/alJd1BLypyK9Mpaw@kernel.org Link: https://lore.kernel.org/20260709-internal-h-v2-0-695631425968@kernel.org Link: https://lore.kernel.org/20260709-internal-h-v2-1-695631425968@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Muchun Song Acked-by: Vlastimil Babka (SUSE) Acked-by: David Hildenbrand (Arm) Acked-by: Lorenzo Stoakes Acked-by: Pratyush Yadav Acked-by: SJ Park Cc: Alexander Graf Cc: Alexander Potapenko Cc: Brendan Jackman Cc: Brendan Jackman Cc: Dennis Zhou Cc: Dmitry Vyukov Cc: Johannes Weiner Cc: Liam R. Howlett Cc: Marco Elver Cc: Michal Hocko Cc: Oscar Salvador Cc: Pasha Tatashin Cc: Suren Baghdasaryan Cc: Tejun Heo Cc: "Uladzislau Rezki (Sony)" Cc: Zi Yan Signed-off-by: Andrew Morton

mm/hugetlb_cma: validate hugetlb CMA range by zone at reserve time

2026-07-29T04:11:59+00:00

Hugetlb CMA allocation currently has to cope with CMA areas that span multiple zones. Validate the reserved CMA range up front in hugetlb_cma_reserve() so later hugetlb CMA allocations can assume a zone-consistent area. Also drop the pfn_valid() check from cma_validate_zones(). mem_section is not fully initialized at this point, so the check can trigger false warnings. Keep the sanity check in cma_activate_area() instead. Link: https://lore.kernel.org/20260612035903.2468601-13-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Mike Rapoport (Microsoft) Reviewed-by: Oscar Salvador (SUSE) Cc: "Aneesh Kumar K.V" Cc: David Hildenbrand Cc: Frank van der Linden Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Oscar Salvador (SUSE) Cc: "Ritesh Harjani (IBM)" Cc: Usama Arif Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/cma: fix reserved page leak on activation failure

2026-05-29T03:50:34+00:00

If cma_activate_area() fails after allocating only part of the range bitmaps, the cleanup path still has to release the reserved pages when CMA_RESERVE_PAGES_ON_ERROR is clear. That is still worth doing even in this __init path. A bitmap_zalloc() failure does not necessarily mean the system cannot make further progress: freeing the reserved CMA pages can return a substantial amount of memory to the buddy allocator and may relieve the temporary memory shortage that caused the allocation failure in the first place. However, the cleanup path currently uses the bitmap-freeing bound for page release as well. That is only correct for ranges whose bitmap allocation already succeeded. The failed range and all later ranges still keep their reserved pages, so a partial bitmap allocation failure can permanently leak them. Fix this by releasing reserved pages for all ranges. Use the saved early_pfn[] value for ranges whose bitmap allocation already succeeded and for the failed range, and use cmr->early_pfn for later ranges whose bitmap allocation was never attempted. Link: https://lore.kernel.org/20260523060123.2207992-1-songmuchun@bytedance.com Fixes: c009da4258f9 ("mm, cma: support multiple contiguous ranges, if requested") Signed-off-by: Muchun Song Reviewed-by: Oscar Salvador (SUSE) Acked-by: Usama Arif Cc: David Hildenbrand Cc: Frank van der Linden Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Signed-off-by: Andrew Morton

Merge tag 'dma-mapping-7.1-2026-04-16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux

2026-04-17T18:12:42+00:00

Pull dma-mapping updates from Marek Szyprowski: - added support for batched cache sync, what improves performance of dma_map/unmap_sg() operations on ARM64 architecture (Barry Song) - introduced DMA_ATTR_CC_SHARED attribute for explicitly shared memory used in confidential computing (Jiri Pirko) - refactored spaghetti-like code in drivers/of/of_reserved_mem.c and its clients (Marek Szyprowski, shared branch with device-tree updates to avoid merge conflicts) - prepared Contiguous Memory Allocator related code for making dma-buf drivers modularized (Maxime Ripard) - added support for benchmarking dma_map_sg() calls to tools/dma utility (Qinxin Xia) * tag 'dma-mapping-7.1-2026-04-16' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux: (24 commits) dma-buf: heaps: system: document system_cc_shared heap dma-buf: heaps: system: add system_cc_shared heap for explicitly shared memory dma-mapping: introduce DMA_ATTR_CC_SHARED for shared memory mm: cma: Export cma_alloc(), cma_release() and cma_get_name() dma: contiguous: Export dev_get_cma_area() dma: contiguous: Make dma_contiguous_default_area static dma: contiguous: Make dev_get_cma_area() a proper function dma: contiguous: Turn heap registration logic around of: reserved_mem: rework fdt_init_reserved_mem_node() of: reserved_mem: clarify fdt_scan_reserved_mem*() functions of: reserved_mem: rearrange code a bit of: reserved_mem: replace CMA quirks by generic methods of: reserved_mem: switch to ops based OF_DECLARE() of: reserved_mem: use -ENODEV instead of -ENOENT of: reserved_mem: remove fdt node from the structure dma-mapping: fix false kernel-doc comment marker dma-mapping: Support batch mode for dma_direct_{map,unmap}_sg dma-mapping: Separate DMA sync issuing and completion waiting arm64: Provide dcache_inval_poc_nosync helper arm64: Provide dcache_clean_poc_nosync helper ...

mm: cma: Export cma_alloc(), cma_release() and cma_get_name()

2026-03-31T11:27:21+00:00

The CMA dma-buf heap uses cma_alloc() and cma_release() to allocate and free, respectively, its CMA buffers, and cma_get_name() to get the name of the heap instance it's going to create. However, these functions are not exported. Since we want to turn the CMA heap into a module, let's export them both. Reviewed-by: T.J. Mercier Acked-by: David Hildenbrand (Arm) Signed-off-by: Maxime Ripard Signed-off-by: Marek Szyprowski Link: https://lore.kernel.org/r/20260331-dma-buf-heaps-as-modules-v4-5-e18fda504419@kernel.org

mm/cma: move put_page_testzero() out of VM_WARN_ON in cma_release()

2026-03-04T17:44:22+00:00

When CONFIG_DEBUG_VM is not set, VM_WARN_ON is a NOP. Putting any statement with side effect inside it is incorrect. Collect all !put_page_testzero() results and check the sum using WARN instead after the loop. It restores the same check in free_contig_range() before commit e0c1326779cc ("mm: page_alloc: add alloc_contig_frozen_{range,pages}()"), the commit prior to the Fixes one. Link: https://lkml.kernel.org/r/20260225031231.2352011-1-ziy@nvidia.com Fixes: 9bda131c6093 ("mm: cma: add cma_alloc_frozen{_compound}()") Signed-off-by: Zi Yan Reported-by: Ron Economos Closes: https://lore.kernel.org/all/1b17c38f-30d3-4bb4-a7e1-e74b19ada885@w6rz.net/ Suggested-by: Kefeng Wang Reviewed-by: Vishal Moola (Oracle) Debugged-by: David Hildenbrand (Arm) Acked-by: David Hildenbrand (Arm) Tested-by: Ron Economos Reviewed-by: Kefeng Wang Reviewed-by: Anshuman Khandual Reviewed-by: SeongJae Park Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm/cma: replace snprintf with strscpy in cma_new_area

2026-02-06T23:47:15+00:00

Replace snprintf("%s", ...) with the faster and more direct strscpy(). Link: https://lkml.kernel.org/r/20260126174516.236968-1-thorsten.blum@linux.dev Signed-off-by: Thorsten Blum Reviewed-by: Andrew Morton Reviewed-by: SeongJae Park Cc: David Hildenbrand Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: cma: add cma_alloc_frozen{_compound}()

2026-01-27T04:02:28+00:00

Introduce cma_alloc_frozen{_compound}() helper to alloc pages without incrementing their refcount, then convert hugetlb cma to use the cma_alloc_frozen_compound() and cma_release_frozen() and remove the unused cma_{alloc,free}_folio(), also move the cma_validate_zones() into mm/internal.h since no outside user. The set_pages_refcounted() is only called to set non-compound pages after above changes, so remove the processing about PageHead. Link: https://lkml.kernel.org/r/20260109093136.1491549-6-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Zi Yan Cc: Brendan Jackman Cc: David Hildenbrand Cc: Jane Chu Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Muchun Song Cc: Oscar Salvador Cc: Sidhartha Kumar Cc: Vlastimil Babka Cc: Claudiu Beznea Cc: Mark Brown Signed-off-by: Andrew Morton

mm: page_alloc: add alloc_contig_frozen_{range,pages}()

2026-01-27T04:02:28+00:00

In order to allocate given range of pages or allocate compound pages without incrementing their refcount, adding two new helper alloc_contig_frozen_{range,pages}() which may be beneficial to some users (eg hugetlb). The new alloc_contig_{range,pages} only take !__GFP_COMP gfp now, and the free_contig_range() is refactored to only free non-compound pages, the only caller to free compound pages in cma_free_folio() is changed accordingly, and the free_contig_frozen_range() is provided to match the alloc_contig_frozen_range(), which is used to free frozen pages. Link: https://lkml.kernel.org/r/20260109093136.1491549-5-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Reviewed-by: Zi Yan Reviewed-by: Sidhartha Kumar Cc: Brendan Jackman Cc: David Hildenbrand Cc: Jane Chu Cc: Johannes Weiner Cc: Matthew Wilcox (Oracle) Cc: Muchun Song Cc: Oscar Salvador Cc: Vlastimil Babka Cc: Claudiu Beznea Cc: Mark Brown Signed-off-by: Andrew Morton