From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A06A27B4F7 for ; Tue, 15 Sep 2026 01:08:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789434512; cv=none; b=gqCqNF4Fy09SfKaAIPkCKrUmMAkiHvCg0YalTxdnI78CbHBzztBF56agTZN6jFcGczsRr6IMT5ve6DCf6OHy/LSrxwKX0HlpWRNCI6izOa95dQy2RmbfQ+dICRhcXDxgmY2Y7K2SjuZJva7U/g8f811dtfzphegkm3KGr93CXIk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789434512; c=relaxed/simple; bh=8o9EZLizKmQZQ+9o6kQH+TEys1kKuWZyCTXLXljoc6U=; h=Date:To:From:Subject:Message-Id; b=LAgtDEfdyGp2QQL7QmuBDlC4AYLxJ5VO3pFNbJaxQRYpNxn46t2fee5g9ld5bXSBqn0EzaYq/uwxXTNR74NTIlFZeG6Dey/pt8LIdJqVJOJPP//0xumLTpsfytacgAcxwjU/HmJJxJFJAUHggZHMVyR7X5Lj+RCuJqTaVsq62bk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=ZNVJuRCv; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ZNVJuRCv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 126F41F000FF; Tue, 15 Sep 2026 01:08:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1789434511; bh=O+mXQzheL0y3fxLkVLmu3oUTjB/UacF0a5b4HjNssJ0=; h=Date:To:From:Subject; b=ZNVJuRCvIRANPTmKuvIVLTKPWwOtDoXtS0IAnYQ7eIDnLKyQcVbY8dkCMRYgfJZwS VRzg4R8ILJq+wuaN4VpSe4xdOv/LCkjxDmP2E2oxn3HftwJT0mF3xrfz66KMzpNnOS QxiQ7/XGoxru2ia8YiZZOXb29S6At5GIOyVlJ59U= Date: Mon, 14 Sep 2026 18:08:30 -0700 To: mm-commits@vger.kernel.org,ljs@kernel.org,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-vma-introduce-and-use-vma_can_merge.patch added to mm-new branch Message-Id: <20260915010831.126F41F000FF@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm/vma: introduce and use vma_[flags_]can_merge() has been added to the -mm mm-new branch. Its filename is mm-vma-introduce-and-use-vma_can_merge.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vma-introduce-and-use-vma_can_merge.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: "Lorenzo Stoakes (ARM)" Subject: mm/vma: introduce and use vma_[flags_]can_merge() Date: Mon, 14 Sep 2026 15:57:23 +0100 Replace the open-coded VMA_SPECIAL_FLAGS check in the VMA merge logic with two new functions vma_flags_can_merge() and vma_can_merge() and update the merge logic to use the former. This abstracts the check and expresses it in terms of the desired behaviour rather than an arbitrary and confusing VMA flag. This also lays the groundwork for making further improvements in VMA flag usage. Also update the userland VMA tests to reflect the change. No functional change intended. Link: https://lore.kernel.org/20260914-b4-mmap-prepare-vma-flag-sanify-v2-3-7d9781ed5361@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton --- include/linux/mm.h | 21 +++++++++++++++++++++ mm/vma.c | 19 +++++++++++-------- tools/testing/vma/include/dup.h | 5 +++++ 3 files changed, 37 insertions(+), 8 deletions(-) --- a/include/linux/mm.h~mm-vma-introduce-and-use-vma_can_merge +++ a/include/linux/mm.h @@ -1613,6 +1613,27 @@ static inline bool vma_is_shared_maywrit } /** + * vma_flags_can_merge() - Do the specified VMA flags permit the VMA to be + * merged with another? + * @flags: The VMA flags to test. + * Returns: true if the flags permit merging, false otherwise. + */ +static inline bool vma_flags_can_merge(const vma_flags_t *flags) +{ + return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); +} + +/** + * vma_can_merge() - Do @vma's flags permit it to be merged with another VMA? + * @vma: The VMA to test. + * Returns: true if the flags permit merging, otherwise false. + */ +static inline bool vma_can_merge(const struct vm_area_struct *vma) +{ + return vma_flags_can_merge(&vma->flags); +} + +/** * vma_kernel_pagesize - Default page size granularity for this VMA. * @vma: The user mapping. * --- a/mm/vma.c~mm-vma-introduce-and-use-vma_can_merge +++ a/mm/vma.c @@ -924,13 +924,14 @@ static __must_check struct vm_area_struc vmg->state = VMA_MERGE_NOMERGE; + if (!vma_flags_can_merge(&vmg->vma_flags)) + return NULL; /* - * If a special mapping or if the range being modified is neither at the - * furthermost left or right side of the VMA, then we have no chance of - * merging and should abort. + * If the range being modified is neither at the furthermost left or + * right side of the VMA, then we have no chance of merging and should + * abort. */ - if (vma_flags_test_any_mask(&vmg->vma_flags, VMA_SPECIAL_FLAGS) || - (!left_side && !right_side)) + if (!left_side && !right_side) return NULL; if (left_side) @@ -1152,9 +1153,11 @@ struct vm_area_struct *vma_merge_new_ran vmg->state = VMA_MERGE_NOMERGE; - /* Special VMAs are unmergeable, also if no prev/next. */ - if (vma_flags_test_any_mask(&vmg->vma_flags, VMA_SPECIAL_FLAGS) || - (!prev && !next)) + if (!vma_flags_can_merge(&vmg->vma_flags)) + return NULL; + + /* VMAs with no prev/next are unmergeable. */ + if (!prev && !next) return NULL; can_merge_left = can_vma_merge_left(vmg); --- a/tools/testing/vma/include/dup.h~mm-vma-introduce-and-use-vma_can_merge +++ a/tools/testing/vma/include/dup.h @@ -1647,3 +1647,8 @@ static inline bool file_is_dev_zero(cons { return file && file->f_op == &zero_fops; } + +static inline bool vma_flags_can_merge(const vma_flags_t *flags) +{ + return !vma_flags_test_any_mask(flags, VMA_SPECIAL_FLAGS); +} _ Patches currently in -mm which might be from ljs@kernel.org are mm-vmpressure-remove-window-size-todo.patch tools-testing-selftests-mm-add-missing-gitignore-entries.patch mm-move-drivers-char-memc-to-mm-char-memc.patch mm-implement-file_is_dev_zero-to-uniquely-identify-dev-zero.patch mm-vma-only-permit-map_private-dev-zero-to-be-mapped-anonymous.patch mm-vma-make-map_private-mapped-dev-zero-mappings-truly-anonymous.patch tools-testing-vma-add-test-to-assert-map_private-dev-zero-is-anon.patch tools-testing-selftests-mm-add-map_private-dev-zero-merge-tests.patch mm-madvise-swap-in-cowd-map_private-file-mappings-on-madv_willneed.patch mm-huge_memory-zap-deposited-page-tables-after-an-rcu-grace-period.patch mm-enable-mmu_gather_rcu_table_free-for-most-2-level-architectures.patch mm-enable-mmu_gather_rcu_table_free-for-mmu-riscv.patch mm-enable-mmu_gather_rcu_table_free-for-mmu-arm.patch mm-enable-mmu_gather_rcu_table_free-for-arc-microblaze-xtensa.patch mm-enable-mmu_gather_rcu_table_free-for-sparc64.patch mm-enable-mmu_gather_rcu_table_free-for-m68k-coldfire.patch mm-enable-mmu_gather_rcu_table_free-for-sh-x2.patch mm-enable-mmu_gather_rcu_table_free-for-m68k-motorola.patch mm-enable-mmu_gather_rcu_table_free-for-sparc32.patch mm-make-userland-page-table-freeing-rcu-safe.patch mm-change-the-contract-for-free_pgtables-update-docs.patch mm-vma-fix-mmap_prepare-file-handling-remove-file_doesnt_need_get.patch mm-vma-predicate-setting-mmap_prepare-vma-fields-on-new-vma-alloc.patch mm-vma-introduce-and-use-vma_can_merge.patch mm-consistently-validate-vma-state-after-mmap-hooks.patch mm-vma-ensure-mmap_prepare-doesnt-set-actions-on-a-mergeable-vma.patch mm-make-map_kernel_pages_-internal-and-unexported.patch mm-vma-tidy-up-map-kernel-pages-enum-values.patch mm-add-mmap-action-for-discontiguous-kernel-page-mapping.patch docs-filesystems-update-mmap_prepare-docs-for-discontig-kernel-pgs.patch drivers-usb-mon-update-to-use-mmap_prepare-map-kernel-pages.patch infiniband-update-hfi1-to-use-remap_vmalloc_range.patch selinux-reject-writable-opens-of-policy-file-drop-mmap-shared-write-check.patch alsa-pcm-use-vm_insert_page-to-map-pcm-status-page.patch bpf-arena-mark-arena_map_mmap-mappings-vm_mixedmap.patch mm-vma-add-vma_is_kernel_owned-predicates.patch mm-vma-only-allow-mmap-to-clear-vma_maywrite_bit-if-kernel-owned.patch mm-vma-add-and-use-vma__is_fixed_mapping.patch scsi-sg-convert-mmap-hook-to-mmap_prepare-and-rework.patch fbdev-defio-assert-fbinfo_virtfb-drop-vm_io-add-vm_mixedmap.patch hsi-cmt_speech-convert-mmap-hook-to-mmap_prepare-refactor.patch mm-gup-error-out-early-on-vma_mayread_bit-vmas.patch uprobes-remove-vm_io-set-vm_mixedmap-for-mapped-kernel-pages.patch mm-mlock-clear-vma_locked_mask-over-mmap-callback.patch mm-mlock-eliminate-weird-vma_io_bit-abuse-and-simplify.patch mm-vma-enforce-that-only-kernel-owned-mappings-may-set-vma_io_bit.patch mm-remove-vma_io_bit-check-in-vma_is_kernel_owned.patch mm-remove-hugetlb_inlineh.patch mm-rename-is_vm_hugetlb_page-to-vma_is_hugetlb.patch mm-drop-some-redundant-checks-around-hugetlb-vmas.patch mm-madvise-update-is_valid_guard_vma-to-use-vma_can_merge.patch mm-vma-introduce-vma_is_persistent.patch mm-uffd-use-predicates-for-userfaultfd-checks.patch mm-madvise-use-predicates-for-madvise-madv_dofork.patch mm-eliminate-vma_special_flags-usage-when-hugetlb-explicitly-tested.patch mm-eliminate-vma_special_flags-check-in-lru_gen_look_around.patch mm-avoid-use-of-vma_special_flags-in-migrate_vma_setup.patch mm-eliminate-vm_special-vma_special_flags.patch fuse-dax-do-not-set-vm_mixedmap.patch mm-huge_memory-remove-vma_is_special_huge.patch mm-vma-introduce-and-use-vma_can_gup.patch