Some nice improvements were made to rwsem in commit:

 424acaae
 rwsem: wake queued readers when writer blocks on active read lock

but this change overlooked that ia64 had defined RWSEM_WAITING_BIAS
as an unsigned value, while the new code required a signed value (as
it is in every other architecture).

This fix suggested by the original patch author: Michel Lespinasse.
Signed-off-by: Tony Luck <tony.luck@intel.com>