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authorMike Kravetz <mike.kravetz@oracle.com>2017-02-23 00:42:49 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2017-02-23 01:41:28 +0100
commitfa4d75c1de13299c61b5e18a1ae46bc00888b599 (patch)
tree73ca3cf8aac2fa991fc7310658145d49772f0b49 /mm/memory.c
parentuserfaultfd: non-cooperative: wake userfaults after UFFDIO_UNREGISTER (diff)
downloadlinux-fa4d75c1de13299c61b5e18a1ae46bc00888b599.tar.xz
linux-fa4d75c1de13299c61b5e18a1ae46bc00888b599.zip
userfaultfd: hugetlbfs: add copy_huge_page_from_user for hugetlb userfaultfd support
userfaultfd UFFDIO_COPY allows user level code to copy data to a page at fault time. The data is copied from user space to a newly allocated huge page. The new routine copy_huge_page_from_user performs this copy. Link: http://lkml.kernel.org/r/20161216144821.5183-17-aarcange@redhat.com Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com> Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com> Cc: Hillf Danton <hillf.zj@alibaba-inc.com> Cc: Michael Rapoport <RAPOPORT@il.ibm.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
-rw-r--r--mm/memory.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/mm/memory.c b/mm/memory.c
index ececdc4a2892..4ade940d105c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4152,6 +4152,31 @@ void copy_user_huge_page(struct page *dst, struct page *src,
copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma);
}
}
+
+long copy_huge_page_from_user(struct page *dst_page,
+ const void __user *usr_src,
+ unsigned int pages_per_huge_page)
+{
+ void *src = (void *)usr_src;
+ void *page_kaddr;
+ unsigned long i, rc = 0;
+ unsigned long ret_val = pages_per_huge_page * PAGE_SIZE;
+
+ for (i = 0; i < pages_per_huge_page; i++) {
+ page_kaddr = kmap_atomic(dst_page + i);
+ rc = copy_from_user(page_kaddr,
+ (const void __user *)(src + i * PAGE_SIZE),
+ PAGE_SIZE);
+ kunmap_atomic(page_kaddr);
+
+ ret_val -= (PAGE_SIZE - rc);
+ if (rc)
+ break;
+
+ cond_resched();
+ }
+ return ret_val;
+}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
#if USE_SPLIT_PTE_PTLOCKS && ALLOC_SPLIT_PTLOCKS