make_pages_present() is dirtying mlocked pages if the VMA is writable, even
though it shouldn't, by telling get_user_pages() to simulate a write fault.

A simple way to test this is to mlock a multi-GB file, and then sync.
The sync will take a long time.

As far as I can see, it should be safe to just not simulate a write fault.

Signed-off-by: Suleiman Souhlal <[EMAIL PROTECTED]>
---
 mm/memory.c |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index f64cbf9..f43c9e8 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2664,18 +2664,17 @@ #endif /* __PAGETABLE_PMD_FOLDED */
 
 int make_pages_present(unsigned long addr, unsigned long end)
 {
-       int ret, len, write;
+       int ret, len;
        struct vm_area_struct * vma;
 
        vma = find_vma(current->mm, addr);
        if (!vma)
                return -1;
-       write = (vma->vm_flags & VM_WRITE) != 0;
        BUG_ON(addr >= end);
        BUG_ON(end > vma->vm_end);
        len = (end+PAGE_SIZE-1)/PAGE_SIZE-addr/PAGE_SIZE;
        ret = get_user_pages(current, current->mm, addr,
-                       len, write, 0, NULL, NULL);
+                       len, 0, 0, NULL, NULL);
        if (ret < 0)
                return ret;
        return ret == len ? 0 : -1;
-- 
1.4.2

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