Re: [PATCH v2 00/10] evacuate struct page from the block layer, introduce __pfn_t

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.