[PATCH] pidhashing: enforce PID_MAX_LIMIT in sysctls

[PATCH] pidhashing: enforce PID_MAX_LIMIT in sysctls

The pid_max sysctl doesn't enforce PID_MAX_LIMIT or sane lower bounds.
RESERVED_PIDS + 1 is the minimum pid_max that won't break alloc_pidmap(), and
PID_MAX_LIMIT may not be aligned to 8*PAGE_SIZE boundaries for unusual values
of PAGE_SIZE, so this also rounds up PID_MAX_LIMIT to it.

Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>