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SubjectRe: [PATCH v2 00/10] evacuate struct page from the block layer, introduce __pfn_t
On Fri, May 08, 2015 at 11:26:01AM +0200, Ingo Molnar wrote:
>
> * Al Viro <viro@ZenIV.linux.org.uk> wrote:
>
> > On Fri, May 08, 2015 at 07:37:59AM +0200, Ingo Molnar wrote:
> >
> > > So if code does iov_iter_get_pages_alloc() on a user address that
> > > has a real struct page behind it - and some other code does a
> > > regular get_user_pages() on it, we'll have two sets of struct page
> > > descriptors, the 'real' one, and a fake allocated one, right?
> >
> > Huh? iov_iter_get_pages() is given an array of pointers to struct
> > page, which it fills with what it finds. iov_iter_get_pages_alloc()
> > *allocates* such an array, fills that with what it finds and gives
> > the allocated array to caller.
> >
> > We are not allocating any struct page instances in either of those.
>
> Ah, stupid me - thanks for the explanation!

My fault, actually - this "pages array" should've been either
"'pages' array" or "array of pointers to struct page".


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