Move userfaultfd_{missing,wp,minor,rwp}() and userfaultfd_protected()
ahead of uffd_disable_huge_pmd_share() and uffd_disable_fault_around()
and make the latter two use the helpers rather than open coded VMA flag
masks.Convert open coded VMA flag test in mfill_get_vma() to userfaultfd_wp() as well. With every user of the per-VMA uffd modes going through the helpers, their underlying representation can be changed in the next step. No functional change. Assisted-by: copilot:claude-opus-5 Signed-off-by: Mike Rapoport (Microsoft) <[email protected]> --- include/linux/userfaultfd_k.h | 70 +++++++++++++++++++++---------------------- mm/userfaultfd.c | 2 +- 2 files changed, 35 insertions(+), 37 deletions(-) diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index 3396d270b159..d8262e3dc134 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -168,42 +168,6 @@ static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma, return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx; } -/* - * Never enable huge pmd sharing on some uffd registered vmas: - * - * - VM_UFFD_WP and VM_UFFD_RWP VMAs, because the write protect / access - * tracking information is per pgtable entry. - * - * - VM_UFFD_MINOR VMAs, because otherwise we would never get minor faults for - * VMAs which share huge pmds. (If you have two mappings to the same - * underlying pages, and fault in the non-UFFD-registered one with a write, - * with huge pmd sharing this would *also* setup the second UFFD-registered - * mapping, and we'd not get minor faults.) - */ -static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma) -{ - return vma_test_any_mask(vma, - mk_vma_flags_from_masks(VMA_UFFD_WP, VMA_UFFD_RWP, - VMA_UFFD_MINOR)); -} - -/* - * Don't do fault around for WP, RWP or MINOR registered uffd range. For - * MINOR registered range, fault around will be a total disaster and ptes can - * be installed without notifications; for WP it should mostly be fine as long - * as the fault around checks for pte_none() before the installation, however - * to be super safe we just forbid it; for RWP, pre-faulted neighbours would - * be indistinguishable from accessed pages in PAGEMAP_SCAN (PAGE_IS_ACCESSED) - * and pollute the tracked working set, so each page must be populated by its - * own fault. - */ -static inline bool uffd_disable_fault_around(struct vm_area_struct *vma) -{ - return vma_test_any_mask(vma, - mk_vma_flags_from_masks(VMA_UFFD_WP, VMA_UFFD_RWP, - VMA_UFFD_MINOR)); -} - static inline bool userfaultfd_missing(const struct vm_area_struct *vma) { return vma_test_any_mask(vma, VMA_UFFD_MISSING); @@ -235,6 +199,40 @@ static inline bool userfaultfd_protected(const struct vm_area_struct *vma) return userfaultfd_wp(vma) || userfaultfd_rwp(vma); } +/* + * Never enable huge pmd sharing on some uffd registered vmas: + * + * - uffd-WP and uffd-RWP VMAs, because the write protect / access tracking + * information is per pgtable entry. + * + * - uffd-MINOR VMAs, because otherwise we would never get minor faults for + * VMAs which share huge pmds. (If you have two mappings to the same + * underlying pages, and fault in the non-UFFD-registered one with a write, + * with huge pmd sharing this would *also* setup the second UFFD-registered + * mapping, and we'd not get minor faults.) + */ +static inline bool uffd_disable_huge_pmd_share(struct vm_area_struct *vma) +{ + return userfaultfd_minor(vma) || userfaultfd_wp(vma) || + userfaultfd_rwp(vma); +} + +/* + * Don't do fault around for WP, RWP or MINOR registered uffd range. For + * MINOR registered range, fault around will be a total disaster and ptes can + * be installed without notifications; for WP it should mostly be fine as long + * as the fault around checks for pte_none() before the installation, however + * to be super safe we just forbid it; for RWP, pre-faulted neighbours would + * be indistinguishable from accessed pages in PAGEMAP_SCAN (PAGE_IS_ACCESSED) + * and pollute the tracked working set, so each page must be populated by its + * own fault. + */ +static inline bool uffd_disable_fault_around(struct vm_area_struct *vma) +{ + return userfaultfd_minor(vma) || userfaultfd_wp(vma) || + userfaultfd_rwp(vma); +} + static inline bool userfaultfd_pte_wp(struct vm_area_struct *vma, pte_t pte) { diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c index 74f04c323c50..32003aa04943 100644 --- a/mm/userfaultfd.c +++ b/mm/userfaultfd.c @@ -261,7 +261,7 @@ static int mfill_get_vma(struct mfill_state *state) * validate 'mode' now that we know the dst_vma: don't allow * a wrprotect copy if the userfaultfd didn't register as WP. */ - if ((flags & MFILL_ATOMIC_WP) && !(dst_vma->vm_flags & VM_UFFD_WP)) + if ((flags & MFILL_ATOMIC_WP) && !userfaultfd_wp(dst_vma)) goto out_unlock; if (is_vm_hugetlb_page(dst_vma)) -- 2.53.0
