[PATCH v6 36/39] mm: avoid use of VMA_SPECIAL_FLAGS in migrate_vma_setup()
flat view
From: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Date: 2026-10-13 15:24:55
Also in:
bpf, dri-devel, fuse-devel, kvm, kvm-riscv, kvmarm, linux-arch, linux-doc, linux-fbdev, linux-fsdevel, linux-mm, linux-perf-users, linux-rdma, linux-riscv, linux-s390, linux-scsi, linux-sound, linux-trace-kernel, linux-usb, lkml, selinux, sparclinux
Subsystem:
memory management, memory management - migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
Revision v6 of 6 in this series; 2 review trailers (2 from subsystem maintainers); queued in linux-next as b6597fb30937 on 2026-10-16.
Revisions (6)
Now we have the expressive vma_is_mm_backed() predicate, use it to determine whether to proceed with migration. This drops the VMA_IO_BIT test, which is safe as mm-managed mappings may not set it. hugetlb mappings are mm-backed but remain explicitly excluded, as the migrate_vma page walk has no hugetlb support. No functional change intended. Reviewed-by: Zi Yan <ziy@nvidia.com> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Signed-off-by: Lorenzo Stoakes (ARM) <ljs@kernel.org> --- mm/migrate_device.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/mm/migrate_device.c b/mm/migrate_device.c
index b9c453c28795..9e19fadfa65c 100644
--- a/mm/migrate_device.c
+++ b/mm/migrate_device.c@@ -739,19 +739,21 @@ static void migrate_vma_unmap(struct migrate_vma *migrate) */ int migrate_vma_setup(struct migrate_vma *args) { + const struct vm_area_struct *vma = args->vma; long nr_pages = (args->end - args->start) >> PAGE_SHIFT; args->start &= PAGE_MASK; args->end &= PAGE_MASK; - if (!args->vma || vma_test_any_mask(args->vma, VMA_SPECIAL_FLAGS) || - vma_is_dax(args->vma)) + if (!vma) + return -EINVAL; + /* The migrate_vma page walk has no hugetlb support. */ + if (!vma_is_mm_backed(vma) || vma_is_hugetlb(vma) || vma_is_dax(vma)) return -EINVAL; if (nr_pages <= 0) return -EINVAL; - if (args->start < args->vma->vm_start || - args->start >= args->vma->vm_end) + if (args->start < vma->vm_start || args->start >= vma->vm_end) return -EINVAL; - if (args->end <= args->vma->vm_start || args->end > args->vma->vm_end) + if (args->end <= vma->vm_start || args->end > vma->vm_end) return -EINVAL; if (!args->src || !args->dst) return -EINVAL;
--
2.55.0