tree 5c1d8d18c65a34eb738c97d75f2c44becdff1de3
parent 29fd66d289f2981e11c550f8b411a6d3d38be0cf
author Hugh Dickins <hughd@google.com> 1332970962 -0700
committer Linus Torvalds <torvalds@linux-foundation.org> 1332980075 -0700

swapon: check validity of swap_flags

Most system calls taking flags first check that the flags passed in are
valid, and that helps userspace to detect when new flags are supported.

But swapon never did so: start checking now, to help if we ever want to
support more swap_flags in future.

It's difficult to get stray bits set in an int, and swapon is not widely
used, so this is most unlikely to break any userspace; but we can just
revert if it turns out to do so.

Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>