[to-be-updated] bpf-arena-mark-arena_map_mmap-mappings-vm_mixedmap.patch removed from -mm tree

[Andrew Morton <akpm@linux-foundation.org>]

The quilt patch titled
     Subject: bpf: arena: mark arena_map_mmap() mappings VM_MIXEDMAP
has been removed from the -mm tree.  Its filename was
     bpf-arena-mark-arena_map_mmap-mappings-vm_mixedmap.patch

This patch was dropped because an updated version will be issued

------------------------------------------------------
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Subject: bpf: arena: mark arena_map_mmap() mappings VM_MIXEDMAP
Date: Mon, 14 Sep 2026 15:57:34 +0100

The bpf_map->ops->map_mmap callback invoked by bpf_map_mmap() can be set
to one of ringbuf_map_mmap_kern(), ringbuf_map_mmap_user(),
array_map_mmap() or arena_map_mmap().

It is convention in mm to mark mappings whose pages the kernel manages
itself with VM_MIXEDMAP, so the core mm knows not to treat them as
ordinary page cache or anonymous memory.

The map_mmap callbacks ringbuf_map_mmap_kern() and ringbuf_map_mmap_user()
use remap_vmalloc_range(), which ultimately invokes vm_insert_page() and
so marks the ranges VM_MIXEDMAP, and array_map_mmap() sets VM_MIXEDMAP
explicitly.

However, the exception to this is arena_map_mmap(), which doesn't set the
flag.

This patch corrects this and updates the comment to reflect it.

The pages are refcounted and vm_normal_page() finds them regardless of the
flag, and VM_DONTEXPAND remains set (marking the memory as VM_SPECIAL and
thus unmergeable).  The one effect is that NUMA balancing now skips these
VMAs, as it already does for the other bpf map mappings, which is the
reason array_map_mmap() gives for setting the flag.

The intent of this patch is to be able to establish the invariant that
only PFN-mapped or mixed map ranges may clear the VM_MAYWRITE flag, as is
done in bpf_map_mmap().

Link: https://lore.kernel.org/20260914-b4-mmap-prepare-vma-flag-sanify-v2-14-7d9781ed5361@kernel.org
Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 kernel/bpf/arena.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/bpf/arena.c~bpf-arena-mark-arena_map_mmap-mappings-vm_mixedmap
+++ a/kernel/bpf/arena.c
@@ -620,8 +620,9 @@ static int arena_map_mmap(struct bpf_map
 	 * clears VM_MAYEXEC. Set VM_DONTEXPAND to avoid potential change
 	 * of user_vm_start. Set VM_DONTCOPY to prevent arena VMA from
 	 * being copied into the child process on fork.
+	 * This is a kernel page so set VM_MIXEDMAP.
 	 */
-	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTCOPY);
+	vm_flags_set(vma, VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTCOPY);
 	vma->vm_ops = &arena_vm_ops;
 	return 0;
 }
_

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-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