From: Gregory Price <gourry@gourry.net>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
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Subject: Re: [PATCH v3 03/40] mm/vma: introduce and use vma_[flags_]can_merge()
Date: Thu, 24 Sep 2026 12:38:08 -0400 [thread overview]
Message-ID: <arVRqJZkql6sGunt@gourry-fedora-PF4VCD3F> (raw)
In-Reply-To: <20260917-b4-mmap-prepare-vma-flag-sanify-v3-3-4583d8a23bca@kernel.org>
On Thu, Sep 17, 2026 at 05:22:12PM +0100, Lorenzo Stoakes (ARM) wrote:
> 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.
>
> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Reviewed-by: Gregory Price (Meta) <gourry@gourry.net>
next prev parent reply other threads:[~2026-09-24 16:38 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-17 16:22 [PATCH v3 00/40] mm: make VMA flag semantics explicit, eliminate VM_SPECIAL Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 01/40] mm/vma: fix mmap_prepare file handling, remove file_doesnt_need_get Lorenzo Stoakes (ARM)
2026-09-23 15:21 ` Suren Baghdasaryan
2026-09-23 15:46 ` Lorenzo Stoakes (ARM)
2026-09-23 15:59 ` Suren Baghdasaryan
2026-09-24 2:20 ` Zi Yan
2026-09-24 10:03 ` Lorenzo Stoakes (ARM)
2026-09-24 16:28 ` Gregory Price
2026-09-25 9:30 ` Lorenzo Stoakes (ARM)
2026-09-24 19:00 ` Liam R. Howlett
2026-09-25 9:12 ` Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 02/40] mm/vma: predicate setting mmap_prepare VMA fields on new vma alloc Lorenzo Stoakes (ARM)
2026-09-23 15:32 ` Suren Baghdasaryan
2026-09-23 15:53 ` Lorenzo Stoakes (ARM)
2026-09-23 16:09 ` Suren Baghdasaryan
2026-09-23 17:07 ` Lorenzo Stoakes (ARM)
2026-09-23 17:33 ` Lorenzo Stoakes (ARM)
2026-09-24 2:25 ` Zi Yan
2026-09-17 16:22 ` [PATCH v3 03/40] mm/vma: introduce and use vma_[flags_]can_merge() Lorenzo Stoakes (ARM)
2026-09-23 16:23 ` Suren Baghdasaryan
2026-09-24 2:27 ` Zi Yan
2026-09-24 16:38 ` Gregory Price [this message]
2026-09-17 16:22 ` [PATCH v3 04/40] mm: consistently validate VMA state after mmap[_prepare] hooks Lorenzo Stoakes (ARM)
2026-09-23 16:47 ` Suren Baghdasaryan
2026-09-23 17:00 ` Lorenzo Stoakes (ARM)
2026-09-24 2:52 ` Zi Yan
2026-09-24 10:06 ` Lorenzo Stoakes (ARM)
2026-09-24 17:17 ` Gregory Price
2026-09-25 12:51 ` Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 05/40] mm/vma: ensure mmap_prepare doesn't set actions on a mergeable vma Lorenzo Stoakes (ARM)
2026-09-24 18:00 ` Gregory Price
2026-09-25 9:51 ` Lorenzo Stoakes (ARM)
2026-09-24 19:28 ` Zi Yan
2026-09-25 9:55 ` Lorenzo Stoakes (ARM)
2026-09-25 7:28 ` Suren Baghdasaryan
2026-09-25 9:53 ` Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 06/40] mm: make map_kernel_pages_[prepare,complete] internal and unexported Lorenzo Stoakes (ARM)
2026-09-24 19:30 ` Zi Yan
2026-09-25 7:35 ` Suren Baghdasaryan
2026-09-17 16:22 ` [PATCH v3 07/40] mm/vma: tidy up map kernel pages enum values Lorenzo Stoakes (ARM)
2026-09-24 19:30 ` Zi Yan
2026-09-25 7:37 ` Suren Baghdasaryan
2026-09-17 16:22 ` [PATCH v3 08/40] mm: add mmap action for discontiguous kernel page mapping Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 09/40] docs: filesystems: update mmap_prepare docs for discontig kernel pgs Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 10/40] drivers/usb/mon: update to use mmap_prepare + map kernel pages Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 11/40] infiniband: update hfi1 to use remap_vmalloc_range() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 12/40] selinux: reject writable opens of policy file, drop mmap shared/write check Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 13/40] ALSA: pcm: use vm_insert_page() to map PCM status page Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 14/40] bpf: arena: mark arena_map_mmap() mappings VM_MIXEDMAP Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 15/40] mm/vma: add vma[_flags]_is_kernel_owned() predicates Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 16/40] mm/vma: only allow mmap to clear VMA_MAYWRITE_BIT if kernel-owned Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 17/40] mm/vma: add and use vma_[flags]_is_fixed_mapping Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 18/40] scsi: sg: convert mmap hook to mmap_prepare and rework Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 19/40] fbdev: defio: assert FBINFO_VIRTFB, drop VM_IO, add VM_MIXEDMAP Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 20/40] HSI: cmt_speech: convert mmap hook to mmap_prepare, refactor Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 21/40] mm/gup: error out early on !VMA_MAYREAD_BIT VMAs Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 22/40] uprobes: remove VM_IO, set VM_MIXEDMAP for mapped kernel pages Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 23/40] mm/mlock: clear VMA_LOCKED_MASK over mmap callback Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 24/40] mm/mlock: eliminate weird VMA_IO_BIT abuse and simplify Lorenzo Stoakes (ARM)
2026-09-23 20:06 ` Zi Yan
2026-09-24 10:21 ` Lorenzo Stoakes (ARM)
2026-09-24 15:50 ` Zi Yan
2026-09-25 9:35 ` Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 25/40] mm/vma: enforce that only kernel-owned mappings may set VMA_IO_BIT Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 26/40] mm: remove VMA_IO_BIT check in vma[_flags]_is_kernel_owned() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 27/40] mm: remove hugetlb_inline.h Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 28/40] mm: rename is_vm_hugetlb_page() to vma_is_hugetlb() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 29/40] mm: drop some redundant checks around hugetlb VMAs Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 30/40] mm/madvise: update is_valid_guard_vma() to use vma_can_merge() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 31/40] mm/vma: introduce vma[_flags]_is_persistent() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 32/40] mm/uffd: use predicates for userfaultfd checks Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 33/40] mm/madvise: use predicates for madvise(..., MADV_DOFORK) Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 34/40] mm: eliminate VMA_SPECIAL_FLAGS usage when hugetlb explicitly tested Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 35/40] mm: eliminate VMA_SPECIAL_FLAGS check in lru_gen_look_around() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 36/40] mm: avoid use of VMA_SPECIAL_FLAGS in migrate_vma_setup() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 37/40] mm: eliminate VM_SPECIAL, VMA_SPECIAL_FLAGS Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 38/40] fuse: dax: do not set VM_MIXEDMAP Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 39/40] mm/huge_memory: remove vma_is_special_huge() Lorenzo Stoakes (ARM)
2026-09-17 16:22 ` [PATCH v3 40/40] mm/vma: introduce and use vma[_flags]_can_gup() Lorenzo Stoakes (ARM)
2026-09-17 21:23 ` [PATCH v3 00/40] mm: make VMA flag semantics explicit, eliminate VM_SPECIAL Andrew Morton
2026-09-23 8:57 ` Lorenzo Stoakes (ARM)
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