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Diffstat (limited to 'mm/gup.c')
-rw-r--r--mm/gup.c30
1 files changed, 24 insertions, 6 deletions
diff --git a/mm/gup.c b/mm/gup.c
index 2493ffa10f4b..3bbfae411880 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -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)