[PATCH] get_user_pages: kill get_page_map

Since its birth, get_user_pages has been calling a misguided get_page_map
function.  follow_page has already returned NULL if the pfn is invalid, we
cannot reach an invalid pfn from a validated struct page.

Remove get_page_map, and the messy rewind in get_user_pages to cope with
its failure.  Oh, and could we please call that "struct page *page" like
everywhere else, instead of "struct page *map"?

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>