IB/ehca: Change idr spinlocks into rwlocks

This eliminates lock contention among IRQs as well as the need to
disable IRQs around idr_find, because there are no IRQ writers.

Signed-off-by: Joachim Fenkes <fenkes@de.ibm.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
diff --git a/drivers/infiniband/hw/ehca/ehca_classes.h b/drivers/infiniband/hw/ehca/ehca_classes.h
index 8580f2a..f1e0db2 100644
--- a/drivers/infiniband/hw/ehca/ehca_classes.h
+++ b/drivers/infiniband/hw/ehca/ehca_classes.h
@@ -293,8 +293,8 @@
 int ehca_init_mrmw_cache(void);
 void ehca_cleanup_mrmw_cache(void);
 
-extern spinlock_t ehca_qp_idr_lock;
-extern spinlock_t ehca_cq_idr_lock;
+extern rwlock_t ehca_qp_idr_lock;
+extern rwlock_t ehca_cq_idr_lock;
 extern struct idr ehca_qp_idr;
 extern struct idr ehca_cq_idr;