IB/mthca: Return actual capacity from create_srq

Have mthca's create_srq method return the actual capacity of the SRQ
that gets created.  Also update comments in <rdma/ib_verbs.h> to
clarify that this is what is expected from ib_create_srq().

Signed-off-by: Dotan Barak <dotanb@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

include/rdma/ib_verbs.h

diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 010287c..c1ad627 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1100,7 +1100,9 @@
  * ib_create_srq - Creates a SRQ associated with the specified protection
  *   domain.
  * @pd: The protection domain associated with the SRQ.
- * @srq_init_attr: A list of initial attributes required to create the SRQ.
+ * @srq_init_attr: A list of initial attributes required to create the
+ *   SRQ.  If SRQ creation succeeds, then the attributes are updated to
+ *   the actual capabilities of the created SRQ.
  *
  * srq_attr->max_wr and srq_attr->max_sge are read the determine the
  * requested size of the SRQ, and set to the actual values allocated
@@ -1159,7 +1161,9 @@
  * ib_create_qp - Creates a QP associated with the specified protection
  *   domain.
  * @pd: The protection domain associated with the QP.
- * @qp_init_attr: A list of initial attributes required to create the QP.
+ * @qp_init_attr: A list of initial attributes required to create the
+ *   QP.  If QP creation succeeds, then the attributes are updated to
+ *   the actual capabilities of the created QP.
  */
 struct ib_qp *ib_create_qp(struct ib_pd *pd,
 			   struct ib_qp_init_attr *qp_init_attr);