On Fri, May 08, 2015 at 07:37:59AM +0200, Ingo Molnar wrote:
same as iov_iter_get_pages(), except that pages array is
(kmalloc if possible, vmalloc if that fails) and left for caller to
free. Lustre and NFS ->direct_IO() switched to it.
Signed-off-by: Al Viro <viro(a)zeniv.linux.org.uk>
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
We are not allocating any struct page instances in either of those.