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authorAndrea Arcangeli <aarcange@redhat.com>2011-01-13 15:46:37 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2011-01-13 17:32:39 -0800
commit14fd403f2146f740942d78af4e0ee59396ad8eab (patch)
treec87734f6c6639684208d36548aa3687c6f460e23 /include/linux/mm.h
parent2609ae6d10af0531e826335bd1445d1ace17c847 (diff)
thp: export maybe_mkwrite
huge_memory.c needs it too when it fallbacks in copying hugepages into regular fragmented pages if hugepage allocation fails during COW. Signed-off-by: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mm.h')
-rw-r--r--include/linux/mm.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a2718e1ed585..6bef67d74adf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -430,6 +430,19 @@ static inline void set_compound_order(struct page *page, unsigned long order)
}
/*
+ * Do pte_mkwrite, but only if the vma says VM_WRITE. We do this when
+ * servicing faults for write access. In the normal case, do always want
+ * pte_mkwrite. But get_user_pages can cause write faults for mappings
+ * that do not have writing enabled, when used by access_process_vm.
+ */
+static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
+{
+ if (likely(vma->vm_flags & VM_WRITE))
+ pte = pte_mkwrite(pte);
+ return pte;
+}
+
+/*
* Multiple processes may "see" the same page. E.g. for untouched
* mappings of /dev/null, all processes see the same page full of
* zeroes, and text pages of executables and shared libraries have