From 8bf792b7afcb5d1e4ec4e9ed4204a10b58cdbf77 Mon Sep 17 00:00:00 2001 From: "Lorenzo Stoakes (ARM)" Date: Tue, 13 Oct 2026 16:05:16 +0100 Subject: [PATCH] mm: avoid use of VMA_SPECIAL_FLAGS in migrate_vma_setup() 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. Link: https://lore.kernel.org/20261013-b4-mmap-prepare-vma-flag-sanify-v6-36-1aa3c9b139f9@kernel.org Signed-off-by: Lorenzo Stoakes (ARM) Signed-off-by: Andrew Morton Reviewed-by: Zi Yan Acked-by: David Hildenbrand (Arm) Cc: Liam R. Howlett Cc: Vlastimil Babka Cc: Jann Horn Cc: Pedro Falcato Cc: Mike Rapoport Cc: Suren Baghdasaryan 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: Gregory Price 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 --- 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;