[PATCH] cpuset: might_sleep_if check in cpuset_zones_allowed

It's too easy to incorrectly call cpuset_zone_allowed() in an atomic
context without __GFP_HARDWALL set, and when done, it is not noticed until
a tight memory situation forces allocations to be tried outside the current
cpuset.

Add a 'might_sleep_if()' check, to catch this earlier on, instead of
waiting for a similar check in the mutex_lock() code, which is only rarely
invoked.

Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>