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>

3 files changed, 9 insertions, 7 deletions

diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c
index 815f94c17c48..d29e3c943399 100644
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/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);
 
diff --git a/drivers/infiniband/sw/rxe/rxe.c b/drivers/infiniband/sw/rxe/rxe.c
index 7121e1b1eb89..10999fa69281 100644
--- a/drivers/infiniband/sw/rxe/rxe.c
+++ b/drivers/infiniband/sw/rxe/rxe.c
@@ -91,7 +91,8 @@ static void rxe_init_device_param(struct rxe_dev *rxe)
 	rxe->attr.max_qp			= RXE_MAX_QP;
 	rxe->attr.max_qp_wr			= RXE_MAX_QP_WR;
 	rxe->attr.device_cap_flags		= RXE_DEVICE_CAP_FLAGS;
-	rxe->attr.max_sge			= RXE_MAX_SGE;
+	rxe->attr.max_send_sge			= RXE_MAX_SGE;
+	rxe->attr.max_recv_sge			= RXE_MAX_SGE;
 	rxe->attr.max_sge_rd			= RXE_MAX_SGE_RD;
 	rxe->attr.max_cq			= RXE_MAX_CQ;
 	rxe->attr.max_cqe			= (1 << RXE_MAX_LOG_CQE) - 1;
diff --git a/drivers/infiniband/sw/rxe/rxe_qp.c b/drivers/infiniband/sw/rxe/rxe_qp.c
index 9f83fc982f31..c58452daffc7 100644
--- a/drivers/infiniband/sw/rxe/rxe_qp.c
+++ b/drivers/infiniband/sw/rxe/rxe_qp.c
@@ -49,9 +49,9 @@ static int rxe_qp_chk_cap(struct rxe_dev *rxe, struct ib_qp_cap *cap,
 		goto err1;
 	}
 
-	if (cap->max_send_sge > rxe->attr.max_sge) {
+	if (cap->max_send_sge > rxe->attr.max_send_sge) {
 		pr_warn("invalid send sge = %d > %d\n",
-			cap->max_send_sge, rxe->attr.max_sge);
+			cap->max_send_sge, rxe->attr.max_send_sge);
 		goto err1;
 	}
 
@@ -62,9 +62,9 @@ static int rxe_qp_chk_cap(struct rxe_dev *rxe, struct ib_qp_cap *cap,
 			goto err1;
 		}
 
-		if (cap->max_recv_sge > rxe->attr.max_sge) {
+		if (cap->max_recv_sge > rxe->attr.max_recv_sge) {
 			pr_warn("invalid recv sge = %d > %d\n",
-				cap->max_recv_sge, rxe->attr.max_sge);
+				cap->max_recv_sge, rxe->attr.max_recv_sge);
 			goto err1;
 		}
 	}