IB/core: add max_send_sge and max_recv_sge attributes

This patch replaces the ib_device_attr.max_sge with max_send_sge and
max_recv_sge. It allows ulps to take advantage of devices that have very
different send and recv sge depths.  For example cxgb4 has a max_recv_sge
of 4, yet a max_send_sge of 16.  Splitting out these attributes allows
much more efficient use of the SQ for cxgb4 with ulps that use the RDMA_RW
API. Consider a large RDMA WRITE that has 16 scattergather entries.
With max_sge of 4, the ulp would send 4 WRITE WRs, but with max_sge of
16, it can be done with 1 WRITE WR.

Acked-by: Sagi Grimberg <sagi@grimberg.me>
Acked-by: Christoph Hellwig <hch@lst.de>
Acked-by: Selvin Xavier <selvin.xavier@broadcom.com>
Acked-by: Shiraz Saleem <shiraz.saleem@intel.com>
Acked-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>

drivers/infiniband/sw/rdmavt/qp.c

@@ -780,14 +780,15 @@ struct ib_qp *rvt_create_qp(struct ib_pd *ibpd,
 	if (!rdi)
 		return ERR_PTR(-EINVAL);
 
-	if (init_attr->cap.max_send_sge > rdi->dparms.props.max_sge ||
+	if (init_attr->cap.max_send_sge > rdi->dparms.props.max_send_sge ||
 	    init_attr->cap.max_send_wr > rdi->dparms.props.max_qp_wr ||
 	    init_attr->create_flags)
 		return ERR_PTR(-EINVAL);
 
 	/* Check receive queue parameters if no SRQ is specified. */
 	if (!init_attr->srq) {
-		if (init_attr->cap.max_recv_sge > rdi->dparms.props.max_sge ||
+		if (init_attr->cap.max_recv_sge >
+		    rdi->dparms.props.max_recv_sge ||
 		    init_attr->cap.max_recv_wr > rdi->dparms.props.max_qp_wr)
 			return ERR_PTR(-EINVAL);