* + mm-vma-introduce-and-use-vma_can_merge.patch added to mm-unstable branch
@ 2026-10-10 22:01 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2026-10-10 22:01 UTC (permalink / raw)
To: mm-commits, ljs, akpm
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:
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*** 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)" <ljs@kernel.org>
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) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Kiryl Shutsemau <kas@kernel.org>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: James Bottomley <james.bottomley@hansenpartnership.com>
Cc: Martin K. Petersen <mkp@kernel.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Harry Yoo <harry@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Youngjun Park <youngjun.park@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Xu Xin <xu.xin@linux.dev>
Cc: Ihor Solodrai <ihor.solodrai@linux.dev>
Cc: Bert Karwatzki <spasswolf@web.de>
---
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
^ permalink raw reply [flat|nested] 5+ messages in thread* + mm-vma-introduce-and-use-vma_can_merge.patch added to mm-unstable branch
@ 2026-10-13 18:51 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2026-10-13 18:51 UTC (permalink / raw)
To: mm-commits, ljs, akpm
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)" <ljs@kernel.org>
Subject: mm/vma: introduce and use vma_[flags_]can_merge()
Date: Tue, 13 Oct 2026 16:04:42 +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/20261013-b4-mmap-prepare-vma-flag-sanify-v6-2-1aa3c9b139f9@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Kiryl Shutsemau <kas@kernel.org>
Cc: Doug Gilbert <dgilbert@interlog.com>
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Cc: Martin K. Petersen <mkp@kernel.org>
Cc: Simona Vetter <simona@ffwll.ch>
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Cc: Sebastian Reichel <sre@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
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Cc: Borislav Petkov <bp@alien8.de>
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Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
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Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
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Cc: Will Deacon <will@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Paul Walmsley <pjw@kernel.org>
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Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
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Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Youngjun Park <youngjun.park@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Xu Xin <xu.xin@linux.dev>
Cc: Ihor Solodrai <ihor.solodrai@linux.dev>
Cc: Bert Karwatzki <spasswolf@web.de>
---
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-assert-mmap-lock-held-use-new-flags-api-in-vm_insert_page.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-vma-introduce-vma_is_mm_backed.patch
mm-madvise-update-is_valid_guard_vma-to-use-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
^ permalink raw reply [flat|nested] 5+ messages in thread* + mm-vma-introduce-and-use-vma_can_merge.patch added to mm-unstable branch
@ 2026-10-03 23:58 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2026-10-03 23:58 UTC (permalink / raw)
To: mm-commits, ljs, akpm
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)" <ljs@kernel.org>
Subject: mm/vma: introduce and use vma_[flags_]can_merge()
Date: Sat, 03 Oct 2026 17:32:33 +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/20261003-b4-mmap-prepare-vma-flag-sanify-v4-2-a1f052500fd7@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Kiryl Shutsemau <kas@kernel.org>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: James Bottomley <james.bottomley@hansenpartnership.com>
Cc: Martin K. Petersen <mkp@kernel.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Harry Yoo <harry@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Youngjun Park <youngjun.park@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Xu Xin <xu.xin@linux.dev>
---
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-mremap-fix-locked_vm-leak-from-mremap_dontunmap-self-merge.patch
mm-mremap-fix-locked_vm-leak-by-splitting-vma-for-mremap_dontunmap.patch
drivers-char-mem-mmap-readonly-map_shared-dev-zero-correctly.patch
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-khugepaged-deposit-a-newly-allocated-page-table-on-collapse.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-userland-pgtable-freeing-is-rcu-safe-now-remove-leftover-bits.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-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
^ permalink raw reply [flat|nested] 5+ messages in thread* + mm-vma-introduce-and-use-vma_can_merge.patch added to mm-unstable branch
@ 2026-10-03 23:34 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2026-10-03 23:34 UTC (permalink / raw)
To: mm-commits, ljs, akpm
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)" <ljs@kernel.org>
Subject: mm/vma: introduce and use vma_[flags_]can_merge()
Date: Sat, 03 Oct 2026 17:32:33 +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/20261003-b4-mmap-prepare-vma-flag-sanify-v4-2-a1f052500fd7@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Jann Horn <jannh@google.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Nico Pache <nico.pache@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Usama Arif <usama.arif@linux.dev>
Cc: Kiryl Shutsemau <kas@kernel.org>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: James Bottomley <james.bottomley@hansenpartnership.com>
Cc: Martin K. Petersen <mkp@kernel.org>
Cc: Simona Vetter <simona@ffwll.ch>
Cc: Helge Deller <deller@gmx.de>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Harry Yoo <harry@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: David Airlie <airlied@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Oliver Upton <oupton@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Ying Huang <ying.huang@linux.alibaba.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Youngjun Park <youngjun.park@lge.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Qi Zheng <qi.zheng@linux.dev>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Wei Xu <weixugc@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Xu Xin <xu.xin@linux.dev>
---
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-mremap-fix-locked_vm-leak-from-mremap_dontunmap-self-merge.patch
mm-mremap-fix-locked_vm-leak-by-splitting-vma-for-mremap_dontunmap.patch
drivers-char-mem-mmap-readonly-map_shared-dev-zero-correctly.patch
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-khugepaged-deposit-a-newly-allocated-page-table-on-collapse.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-userland-pgtable-freeing-is-rcu-safe-now-remove-leftover-bits.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-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
^ permalink raw reply [flat|nested] 5+ messages in thread* + mm-vma-introduce-and-use-vma_can_merge.patch added to mm-unstable branch
@ 2026-09-17 21:24 Andrew Morton
0 siblings, 0 replies; 5+ messages in thread
From: Andrew Morton @ 2026-09-17 21:24 UTC (permalink / raw)
To: mm-commits, ljs, akpm
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)" <ljs@kernel.org>
Subject: mm/vma: introduce and use vma_[flags_]can_merge()
Date: Thu, 17 Sep 2026 17:22:12 +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/20260917-b4-mmap-prepare-vma-flag-sanify-v3-3-4583d8a23bca@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@kernel.org>
Cc: Anup Patel <anup@brainfault.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <baoquan.he@linux.dev>
Cc: Barry Song <baohua@kernel.org>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>
Cc: Dave Airlie <airlied@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: Eduard Zingerman <eddyz87@gmail.com>
Cc: Emil Tsalapatis <emil@etsalapatis.com>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Gregory Price <gourry@gourry.net>
Cc: Harry Yoo <harry@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Bottomley <james.bottomley@HansenPartnership.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jaya Kumar <jayalk@intworks.biz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kiryl Shutsemau <kas@kernel.org>
Cc: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Marc Rutland <mark.rutland@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Maxime Ripard <mripard@kernel.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Namhyung kim <namhyung@kernel.org>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Sebastian Reichel <sre@kernel.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Takashi Iwai (SUSE) <tiwai@suse.de>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: Thomas Zimemrmann <tzimmermann@suse.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Wei Xu <weixugc@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
---
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
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
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