The patch titled
Subject: userfaultfd: hugetlbfs: add hugetlb_mcopy_atomic_pte for userfaultfd support
has been added to the -mm tree. Its filename is
userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: userfaultfd: hugetlbfs: add hugetlb_mcopy_atomic_pte for userfaultfd support
hugetlb_mcopy_atomic_pte is the low level routine that implements the
userfaultfd UFFDIO_COPY command. It is based on the existing
mcopy_atomic_pte routine with modifications for huge pages.
Link: http://lkml.kernel.org/r/20161216144821.5183-18-aarcange@xxxxxxxxxx
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Signed-off-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hillf Danton <hillf.zj@xxxxxxxxxxxxxxx>
Cc: Michael Rapoport <RAPOPORT@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/hugetlb.h | 7 +++
mm/hugetlb.c | 81 ++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)
diff -puN include/linux/hugetlb.h~userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support include/linux/hugetlb.h
--- a/include/linux/hugetlb.h~userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support
+++ a/include/linux/hugetlb.h
@@ -81,6 +81,11 @@ void hugetlb_show_meminfo(void);
unsigned long hugetlb_total_pages(void);
int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long address, unsigned int flags);
+int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
+ struct vm_area_struct *dst_vma,
+ unsigned long dst_addr,
+ unsigned long src_addr,
+ struct page **pagep);
int hugetlb_reserve_pages(struct inode *inode, long from, long to,
struct vm_area_struct *vma,
vm_flags_t vm_flags);
@@ -149,6 +154,8 @@ static inline void hugetlb_show_meminfo(
#define is_hugepage_only_range(mm, addr, len) 0
#define hugetlb_free_pgd_range(tlb, addr, end, floor, ceiling) ({BUG(); 0; })
#define hugetlb_fault(mm, vma, addr, flags) ({ BUG(); 0; })
+#define hugetlb_mcopy_atomic_pte(dst_mm, dst_pte, dst_vma, dst_addr, \
+ src_addr, pagep) ({ BUG(); 0; })
#define huge_pte_offset(mm, address) 0
static inline int dequeue_hwpoisoned_huge_page(struct page *page)
{
diff -puN mm/hugetlb.c~userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support mm/hugetlb.c
--- a/mm/hugetlb.c~userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support
+++ a/mm/hugetlb.c
@@ -3929,6 +3929,87 @@ out_mutex:
return ret;
}
+/*
+ * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with
+ * modifications for huge pages.
+ */
+int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm,
+ pte_t *dst_pte,
+ struct vm_area_struct *dst_vma,
+ unsigned long dst_addr,
+ unsigned long src_addr,
+ struct page **pagep)
+{
+ struct hstate *h = hstate_vma(dst_vma);
+ pte_t _dst_pte;
+ spinlock_t *ptl;
+ int ret;
+ struct page *page;
+
+ if (!*pagep) {
+ ret = -ENOMEM;
+ page = alloc_huge_page(dst_vma, dst_addr, 0);
+ if (IS_ERR(page))
+ goto out;
+
+ ret = copy_huge_page_from_user(page,
+ (const void __user *) src_addr,
+ pages_per_huge_page(h));
+
+ /* fallback to copy_from_user outside mmap_sem */
+ if (unlikely(ret)) {
+ ret = -EFAULT;
+ *pagep = page;
+ /* don't free the page */
+ goto out;
+ }
+ } else {
+ page = *pagep;
+ *pagep = NULL;
+ }
+
+ /*
+ * The memory barrier inside __SetPageUptodate makes sure that
+ * preceding stores to the page contents become visible before
+ * the set_pte_at() write.
+ */
+ __SetPageUptodate(page);
+ set_page_huge_active(page);
+
+ ptl = huge_pte_lockptr(h, dst_mm, dst_pte);
+ spin_lock(ptl);
+
+ ret = -EEXIST;
+ if (!huge_pte_none(huge_ptep_get(dst_pte)))
+ goto out_release_unlock;
+
+ ClearPagePrivate(page);
+ hugepage_add_new_anon_rmap(page, dst_vma, dst_addr);
+
+ _dst_pte = make_huge_pte(dst_vma, page, dst_vma->vm_flags & VM_WRITE);
+ if (dst_vma->vm_flags & VM_WRITE)
+ _dst_pte = huge_pte_mkdirty(_dst_pte);
+ _dst_pte = pte_mkyoung(_dst_pte);
+
+ set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte);
+
+ (void)huge_ptep_set_access_flags(dst_vma, dst_addr, dst_pte, _dst_pte,
+ dst_vma->vm_flags & VM_WRITE);
+ hugetlb_count_add(pages_per_huge_page(h), dst_mm);
+
+ /* No need to invalidate - it was non-present before */
+ update_mmu_cache(dst_vma, dst_addr, dst_pte);
+
+ spin_unlock(ptl);
+ ret = 0;
+out:
+ return ret;
+out_release_unlock:
+ spin_unlock(ptl);
+ put_page(page);
+ goto out;
+}
+
long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma,
struct page **pages, struct vm_area_struct **vmas,
unsigned long *position, unsigned long *nr_pages,
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
userfaultfd-hugetlbfs-add-copy_huge_page_from_user-for-hugetlb-userfaultfd-support.patch
userfaultfd-hugetlbfs-add-hugetlb_mcopy_atomic_pte-for-userfaultfd-support.patch
userfaultfd-hugetlbfs-add-__mcopy_atomic_hugetlb-for-huge-page-uffdio_copy.patch
userfaultfd-hugetlbfs-fix-__mcopy_atomic_hugetlb-retry-error-processing.patch
userfaultfd-hugetlbfs-add-userfaultfd-hugetlb-hook.patch
userfaultfd-hugetlbfs-allow-registration-of-ranges-containing-huge-pages.patch
userfaultfd-hugetlbfs-add-userfaultfd_hugetlb-test.patch
userfaultfd-hugetlbfs-userfaultfd_huge_must_wait-for-hugepmd-ranges.patch
userfaultfd-hugetlbfs-reserve-count-on-error-in-__mcopy_atomic_hugetlb.patch
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