IB/mthca: Correct reported SRQ size in MemFree case.

MemFree devices need to reserve one shared receive queue (SRQ) work
request for internal use, so the capacity returned from the create_srq
and query_srq methods should be srq->max - 1.
Signed-off-by: Dotan Barak <dotanb@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

drivers/infiniband/hw/mthca/mthca_srq.c

@@ -271,7 +271,7 @@ int mthca_alloc_srq(struct mthca_dev *dev, struct mthca_pd *pd,
 	srq->first_free = 0;
 	srq->last_free  = srq->max - 1;
 
-	attr->max_wr    = srq->max;
+	attr->max_wr    = (mthca_is_memfree(dev)) ? srq->max - 1 : srq->max;
 	attr->max_sge   = srq->max_gs;
 
 	return 0;
@@ -386,7 +386,7 @@ int mthca_query_srq(struct ib_srq *ibsrq, struct ib_srq_attr *srq_attr)
 	} else
 		srq_attr->srq_limit = 0;
 
-	srq_attr->max_wr  = srq->max;
+	srq_attr->max_wr  = (mthca_is_memfree(dev)) ? srq->max - 1 : srq->max;
 	srq_attr->max_sge = srq->max_gs;
 
 out: