Messages in this thread | | | Date | Fri, 4 Apr 2014 07:52:47 -0700 (PDT) | From | Hugh Dickins <> | Subject | Re: [PATCH] mm: get_user_pages(write,force) refuse to COW in shared areas |
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On Fri, 4 Apr 2014, Kirill A. Shutemov wrote: > > There's comment in do_wp_page() which is not true anymore with patch > applied. It should be fixed.
The * Only catch write-faults on shared writable pages, * read-only shared pages can get COWed by * get_user_pages(.write=1, .force=1).
Yes, I went back and forth on that: I found it difficult to remove that comment without also simplifying the VM_WRITE|VM_SHARED test immediately above it, possibly even looking again at the ordering of those tests.
In the end I decided to leave changing it to when we do the other little cleanups outside get_user_pages(), after it's become clear whether the new EFAULT is troublesome or not. Most of my testing had been without any change in do_wp_page(), so I left that out.
> > Otherwise, looks good to me: > > Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Thanks, Hugh
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