diff options
Diffstat (limited to 'mm/gup.c')
-rw-r--r-- | mm/gup.c | 30 |
1 files changed, 24 insertions, 6 deletions
@@ -597,7 +597,7 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, pte = ptep_get(ptep); if (!pte_present(pte)) goto no_page; - if (pte_protnone(pte) && !gup_can_follow_protnone(flags)) + if (pte_protnone(pte) && !gup_can_follow_protnone(vma, flags)) goto no_page; page = vm_normal_page(vma, address, pte); @@ -714,7 +714,7 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma, if (likely(!pmd_trans_huge(pmdval))) return follow_page_pte(vma, address, pmd, flags, &ctx->pgmap); - if (pmd_protnone(pmdval) && !gup_can_follow_protnone(flags)) + if (pmd_protnone(pmdval) && !gup_can_follow_protnone(vma, flags)) return no_page_table(vma, flags); ptl = pmd_lock(mm, pmd); @@ -844,6 +844,10 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, if (WARN_ON_ONCE(foll_flags & FOLL_PIN)) return NULL; + /* + * We never set FOLL_HONOR_NUMA_FAULT because callers don't expect + * to fail on PROT_NONE-mapped pages. + */ page = follow_page_mask(vma, address, foll_flags, &ctx); if (ctx.pgmap) put_dev_pagemap(ctx.pgmap); @@ -2240,6 +2244,13 @@ static bool is_valid_gup_args(struct page **pages, int *locked, gup_flags |= FOLL_UNLOCKABLE; } + /* + * For now, always trigger NUMA hinting faults. Some GUP users like + * KVM require the hint to be as the calling context of GUP is + * functionally similar to a memory reference from task context. + */ + gup_flags |= FOLL_HONOR_NUMA_FAULT; + /* FOLL_GET and FOLL_PIN are mutually exclusive. */ if (WARN_ON_ONCE((gup_flags & (FOLL_PIN | FOLL_GET)) == (FOLL_PIN | FOLL_GET))) @@ -2564,7 +2575,14 @@ static int gup_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr, struct page *page; struct folio *folio; - if (pte_protnone(pte) && !gup_can_follow_protnone(flags)) + /* + * Always fallback to ordinary GUP on PROT_NONE-mapped pages: + * pte_access_permitted() better should reject these pages + * either way: otherwise, GUP-fast might succeed in + * cases where ordinary GUP would fail due to VMA access + * permissions. + */ + if (pte_protnone(pte)) goto pte_unmap; if (!pte_access_permitted(pte, flags & FOLL_WRITE)) @@ -2983,8 +3001,8 @@ static int gup_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr, unsigned lo if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd) || pmd_devmap(pmd))) { - if (pmd_protnone(pmd) && - !gup_can_follow_protnone(flags)) + /* See gup_pte_range() */ + if (pmd_protnone(pmd)) return 0; if (!gup_huge_pmd(pmd, pmdp, addr, next, flags, @@ -3164,7 +3182,7 @@ static int internal_get_user_pages_fast(unsigned long start, if (WARN_ON_ONCE(gup_flags & ~(FOLL_WRITE | FOLL_LONGTERM | FOLL_FORCE | FOLL_PIN | FOLL_GET | FOLL_FAST_ONLY | FOLL_NOFAULT | - FOLL_PCI_P2PDMA))) + FOLL_PCI_P2PDMA | FOLL_HONOR_NUMA_FAULT))) return -EINVAL; if (gup_flags & FOLL_PIN) |