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 987F034CFB9 for ; Sat, 10 Oct 2026 22:01:30 +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=1791669692; cv=none; b=B/rbIETmOm0GrJqCSbt4DXLKDx+eMvEARJ/pL9tQdu3hKuMrGzwvGEF9Czk+HMeKCDz/x1NwwSKJ8WUd9Nhu1t5Jps4NLQRW3U+26aQHx2sqSkQtHHXdOx7lmhCSnqkF7YR+5M9Lz9GMdzCzdTGl5N00mBFwK9XI+E67HSsaDHs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791669692; c=relaxed/simple; bh=V/FBfUlc9FQ2Bxhdfktln8YNvueUy7CAMMsmOm+4wqc=; h=Date:To:From:Subject:Message-Id; b=WqyyA6bONc3y31ndxKjyh/xTZKn4DVNsx6XQ0/ps8lryOFVTDeV3WsCBQbxlDxvJErh8N1tROdG3gnoX/9j4plftvwJ1Q5XFD7BuVHco2AjlMLBRs3rWh0ajuIcr+oaj0hHksRxW2fdMHxvFzoyho2Oz12sNlzPdZlX0u+ZtfzY= 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=aOrMXwb2; 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="aOrMXwb2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C1241F000FF; Sat, 10 Oct 2026 22:01:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1791669690; bh=20+8MlSfvZF4pvB5gDjxc6LdOC44ipJDyl/9qlvzYzw=; h=Date:To:From:Subject; b=aOrMXwb2YREFpqdPgzGwehsejlV54tuEOcBQhNTZYV59QFDE9CoBbbxQFYpCBqqK5 ImcEmkUi58/9vMG5ndZzdh2QSOnt4+8fyYl8TMstYp6TBn+cn8XSkp7NERc+h0LAWN 3JYdxkHsXbWYk8lhpQanN3S3HL3uZA1QDu2hiCi0= Date: Sat, 10 Oct 2026 15:01:30 -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-unstable branch Message-Id: <20261010220130.6C1241F000FF@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-unstable 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-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm 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: Fri, 09 Oct 2026 19:03:56 +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/20261009-b4-mmap-prepare-vma-flag-sanify-v5-2-923b70125b1e@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Reviewed-by: Gregory Price (Meta) Reviewed-by: Zi Yan Reviewed-by: Suren Baghdasaryan Acked-by: David Hildenbrand (Arm) Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Jann Horn Cc: Pedro Falcato Cc: Mike Rapoport Cc: Michal Hocko Cc: Jonathan Corbet Cc: Greg Kroah-Hartman Cc: Dennis Dalessandro Cc: Jason Gunthorpe Cc: Leon Romanovsky Cc: Paul Moore Cc: Stephen Smalley Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Alexei Starovoitov Cc: Daniel Borkmann Cc: Andrii Nakryiko Cc: Eduard Zingerman Cc: Kumar Kartikeya Dwivedi Cc: Baolin Wang Cc: Nico Pache Cc: Ryan Roberts Cc: Dev Jain Cc: Barry Song Cc: Lance Yang Cc: Usama Arif Cc: Kiryl Shutsemau Cc: Doug Gilbert Cc: James Bottomley Cc: Martin K. Petersen Cc: Simona Vetter Cc: Helge Deller Cc: Sebastian Reichel Cc: John Hubbard Cc: Peter Xu Cc: Masami Hiramatsu Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Dave Hansen Cc: Arnaldo Carvalho de Melo Cc: Namhyung Kim Cc: Mark Rutland Cc: Rik van Riel Cc: Harry Yoo Cc: Juri Lelli Cc: Vincent Guittot Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Will Deacon Cc: Aneesh Kumar K.V Cc: Nicholas Piggin Cc: Arnd Bergmann Cc: Muchun Song Cc: Oscar Salvador Cc: Matthew Wilcox (Oracle) Cc: Jan Kara Cc: Marc Zyngier Cc: Oliver Upton Cc: Catalin Marinas Cc: Madhavan Srinivasan Cc: Anup Patel Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Christian Borntraeger Cc: Janosch Frank Cc: Claudio Imbrenda Cc: Alexander Gordeev Cc: Gerald Schaefer Cc: Heiko Carstens Cc: Vasily Gorbik Cc: David S. Miller Cc: Andreas Larsson Cc: Al Viro Cc: Christian Brauner Cc: Matthew Brost Cc: Joshua Hahn Cc: Rakie Kim Cc: Byungchul Park Cc: Ying Huang Cc: Alistair Popple Cc: Chris Li Cc: Kairui Song Cc: Kemeng Shi Cc: Nhat Pham Cc: Baoquan He Cc: Youngjun Park Cc: Johannes Weiner Cc: Qi Zheng Cc: Shakeel Butt Cc: Axel Rasmussen Cc: Yuanchu Xie Cc: Wei Xu Cc: Chengming Zhou Cc: Michal Hocko Cc: Miklos Szeredi Cc: Xu Xin Cc: Ihor Solodrai Cc: Bert Karwatzki --- 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 @@ -1614,6 +1614,27 @@ 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-vma-fix-mmap_prepare-file-handling-remove-file_doesnt_need_get.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_mm_managed-predicates.patch mm-vma-only-allow-mmap-to-clear-vma_maywrite_bit-if-not-mm-managed.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-mm-managed-mappings-may-not-set-vma_io_bit.patch mm-remove-vma_io_bit-check-in-vma_is_mm_managed.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_mm_backed.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-const-ify-vma_assert_stabilised-and-associated-functions.patch mm-implement-and-use-vma_has_anon_rmap-silence-kcsan.patch mm-update-comments-to-refer-to-anon-rmap-rather-than-anon_vma.patch mm-vma-dont-remove-vma-from-rmap-if-pgoff-unchanged.patch