mm: tighten fault_in_pages_writeable()
authorEric Dumazet <edumazet@google.com>
Fri, 20 May 2016 23:57:53 +0000 (16:57 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 21 May 2016 00:58:30 +0000 (17:58 -0700)
commitb8ca9e3a612eaf3e54c6fa136c62246a1a9aece7
tree4738aff27fdf4f88f77deaebd30454f94ea63a44
parent297880f4af4e492ed5084be9397d65a18ade56ee
mm: tighten fault_in_pages_writeable()

copy_page_to_iter_iovec() is currently the only user of
fault_in_pages_writeable(), and it definitely can use fragments from
high order pages.

Make sure fault_in_pages_writeable() is only touching two adjacent pages
at most, as claimed.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/pagemap.h