get_user_pages() linux kernel

animesh · 03-29-2014, 01:30 PM

get_user_pages() implementation shows that it uses virt_to_page() to extract struct page pointer for given user space, page aligned virtual address.

http://lxr.free-electrons.com/source/mm/nommu.c#L171

virt_to_page() can only be used for directly mapped kernel addresses. How's that get_user_pages() is using the same for user space pages ?

sundialsvcs · 04-08-2014, 10:23 AM

... because, at that point in time, both sets of pages are mapped.