UPSTREAM: bug: switch data corruption check to __must_check

(cherry-picked from 85caa95b)

The CHECK_DATA_CORRUPTION() macro was designed to have callers do
something meaningful/protective on failure.  However, using "return
false" in the macro too strictly limits the design patterns of callers.
Instead, let callers handle the logic test directly, but make sure that
the result IS checked by forcing __must_check (which appears to not be
able to be used directly on macro expressions).

Change-Id: I635dc2f39959104ea8b475d2d5018af3502f33ba
Link: http://lkml.kernel.org/r/20170206204547.GA125312@beast


Signed-off-by: Kees Cook <keescook@chromium.org>
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Satya Tangirala <satyat@google.com>
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>