We ran into the limit with the maximum number of waiters at one of our sites.

This patch increases the number of possible waiters from 2^15 to 2^31 by using
a long for the counter in struct rw_semaphore. S390 and alpha already do this.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Kenneth Chen <kenneth.w.chen@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>