Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 3 Feb 2017 10:29:23 -0800 | Subject | Re: [PATCH v3 0/2] iov_iter: allow iov_iter_get_pages_alloc to allocate more pages per call |
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On Thu, Feb 2, 2017 at 11:29 PM, Al Viro <viro@zeniv.linux.org.uk> wrote: > > get_user_pages() relies upon find_extend_vma() to reject kernel > addresses; the fast side of get_user_pages_fast() doesn't have anything > of that sort
It is *supposed* to have it.
See pte_allows_gup(), for example. In particular, it requires the _PAGE_USER bit in the PTE (and the devpte case should require _PAGE_BIT_DEVMAP).
So no, get_user_pages_fast() can not look up kernel pages. If it does, that would be a bug.
Linus
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