IB/iser: Chain all iser transaction send work requests

Chaning of send work requests benefits performance by
reducing the send queue lock contention (acquired in
ib_post_send) and saves us HW doorbells which is posted
only once.

Currently, in normal IO flows iser does not chain the CDB send
work request with the registration work request. Also in PI
flows, signature work requests are not chained as well.

Lets chain those and post only once.

Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

1 files changed, 53 insertions, 67 deletions

diff --git a/drivers/infiniband/ulp/iser/iser_memory.c b/drivers/infiniband/ulp/iser/iser_memory.c
index 6eadf5188406..09640c811fdd 100644
--- a/drivers/infiniband/ulp/iser/iser_memory.c
+++ b/drivers/infiniband/ulp/iser/iser_memory.c
@@ -664,10 +664,11 @@ iser_inv_rkey(struct ib_send_wr *inv_wr, struct ib_mr *mr)
 {
 	u32 rkey;
 
-	memset(inv_wr, 0, sizeof(*inv_wr));
 	inv_wr->opcode = IB_WR_LOCAL_INV;
 	inv_wr->wr_id = ISER_FASTREG_LI_WRID;
 	inv_wr->ex.invalidate_rkey = mr->rkey;
+	inv_wr->send_flags = 0;
+	inv_wr->num_sge = 0;
 
 	rkey = ib_inc_rkey(mr->rkey);
 	ib_update_fast_reg_key(mr, rkey);
@@ -680,47 +681,38 @@ iser_reg_sig_mr(struct iscsi_iser_task *iser_task,
 		struct iser_mem_reg *prot_reg,
 		struct iser_mem_reg *sig_reg)
 {
-	struct ib_conn *ib_conn = &iser_task->iser_conn->ib_conn;
-	struct ib_send_wr sig_wr, inv_wr;
-	struct ib_send_wr *bad_wr, *wr = NULL;
-	struct ib_sig_attrs sig_attrs;
+	struct iser_tx_desc *tx_desc = &iser_task->desc;
+	struct ib_sig_attrs *sig_attrs = &tx_desc->sig_attrs;
+	struct ib_send_wr *wr;
 	int ret;
 
-	memset(&sig_attrs, 0, sizeof(sig_attrs));
-	ret = iser_set_sig_attrs(iser_task->sc, &sig_attrs);
+	memset(sig_attrs, 0, sizeof(*sig_attrs));
+	ret = iser_set_sig_attrs(iser_task->sc, sig_attrs);
 	if (ret)
 		goto err;
 
-	iser_set_prot_checks(iser_task->sc, &sig_attrs.check_mask);
+	iser_set_prot_checks(iser_task->sc, &sig_attrs->check_mask);
 
 	if (!pi_ctx->sig_mr_valid) {
-		iser_inv_rkey(&inv_wr, pi_ctx->sig_mr);
-		wr = &inv_wr;
+		wr = iser_tx_next_wr(tx_desc);
+		iser_inv_rkey(wr, pi_ctx->sig_mr);
 	}
 
-	memset(&sig_wr, 0, sizeof(sig_wr));
-	sig_wr.opcode = IB_WR_REG_SIG_MR;
-	sig_wr.wr_id = ISER_FASTREG_LI_WRID;
-	sig_wr.sg_list = &data_reg->sge;
-	sig_wr.num_sge = 1;
-	sig_wr.wr.sig_handover.sig_attrs = &sig_attrs;
-	sig_wr.wr.sig_handover.sig_mr = pi_ctx->sig_mr;
+	wr = iser_tx_next_wr(tx_desc);
+	wr->opcode = IB_WR_REG_SIG_MR;
+	wr->wr_id = ISER_FASTREG_LI_WRID;
+	wr->sg_list = &data_reg->sge;
+	wr->num_sge = 1;
+	wr->send_flags = 0;
+	wr->wr.sig_handover.sig_attrs = sig_attrs;
+	wr->wr.sig_handover.sig_mr = pi_ctx->sig_mr;
 	if (scsi_prot_sg_count(iser_task->sc))
-		sig_wr.wr.sig_handover.prot = &prot_reg->sge;
-	sig_wr.wr.sig_handover.access_flags = IB_ACCESS_LOCAL_WRITE |
-					      IB_ACCESS_REMOTE_READ |
-					      IB_ACCESS_REMOTE_WRITE;
-
-	if (!wr)
-		wr = &sig_wr;
+		wr->wr.sig_handover.prot = &prot_reg->sge;
 	else
-		wr->next = &sig_wr;
-
-	ret = ib_post_send(ib_conn->qp, wr, &bad_wr);
-	if (ret) {
-		iser_err("reg_sig_mr failed, ret:%d\n", ret);
-		goto err;
-	}
+		wr->wr.sig_handover.prot = NULL;
+	wr->wr.sig_handover.access_flags = IB_ACCESS_LOCAL_WRITE |
+					   IB_ACCESS_REMOTE_READ |
+					   IB_ACCESS_REMOTE_WRITE;
 	pi_ctx->sig_mr_valid = 0;
 
 	sig_reg->sge.lkey = pi_ctx->sig_mr->lkey;
@@ -744,9 +736,9 @@ static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
 	struct iser_device *device = ib_conn->device;
 	struct ib_mr *mr = rsc->mr;
 	struct ib_fast_reg_page_list *frpl = rsc->frpl;
-	struct ib_send_wr fastreg_wr, inv_wr;
-	struct ib_send_wr *bad_wr, *wr = NULL;
-	int ret, offset, size, plen;
+	struct iser_tx_desc *tx_desc = &iser_task->desc;
+	struct ib_send_wr *wr;
+	int offset, size, plen;
 
 	plen = iser_sg_to_page_vec(mem, device->ib_device, frpl->page_list,
 				   &offset, &size);
@@ -756,34 +748,23 @@ static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
 	}
 
 	if (!rsc->mr_valid) {
-		iser_inv_rkey(&inv_wr, mr);
-		wr = &inv_wr;
+		wr = iser_tx_next_wr(tx_desc);
+		iser_inv_rkey(wr, mr);
 	}
 
-	/* Prepare FASTREG WR */
-	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
-	fastreg_wr.wr_id = ISER_FASTREG_LI_WRID;
-	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
-	fastreg_wr.wr.fast_reg.iova_start = frpl->page_list[0] + offset;
-	fastreg_wr.wr.fast_reg.page_list = frpl;
-	fastreg_wr.wr.fast_reg.page_list_len = plen;
-	fastreg_wr.wr.fast_reg.page_shift = SHIFT_4K;
-	fastreg_wr.wr.fast_reg.length = size;
-	fastreg_wr.wr.fast_reg.rkey = mr->rkey;
-	fastreg_wr.wr.fast_reg.access_flags = (IB_ACCESS_LOCAL_WRITE  |
-					       IB_ACCESS_REMOTE_WRITE |
-					       IB_ACCESS_REMOTE_READ);
-
-	if (!wr)
-		wr = &fastreg_wr;
-	else
-		wr->next = &fastreg_wr;
-
-	ret = ib_post_send(ib_conn->qp, wr, &bad_wr);
-	if (ret) {
-		iser_err("fast registration failed, ret:%d\n", ret);
-		return ret;
-	}
+	wr = iser_tx_next_wr(tx_desc);
+	wr->opcode = IB_WR_FAST_REG_MR;
+	wr->wr_id = ISER_FASTREG_LI_WRID;
+	wr->send_flags = 0;
+	wr->wr.fast_reg.iova_start = frpl->page_list[0] + offset;
+	wr->wr.fast_reg.page_list = frpl;
+	wr->wr.fast_reg.page_list_len = plen;
+	wr->wr.fast_reg.page_shift = SHIFT_4K;
+	wr->wr.fast_reg.length = size;
+	wr->wr.fast_reg.rkey = mr->rkey;
+	wr->wr.fast_reg.access_flags = (IB_ACCESS_LOCAL_WRITE  |
+					IB_ACCESS_REMOTE_WRITE |
+					IB_ACCESS_REMOTE_READ);
 	rsc->mr_valid = 0;
 
 	reg->sge.lkey = mr->lkey;
@@ -795,7 +776,7 @@ static int iser_fast_reg_mr(struct iscsi_iser_task *iser_task,
 		 " length=0x%x\n", reg->sge.lkey, reg->rkey,
 		 reg->sge.addr, reg->sge.length);
 
-	return ret;
+	return 0;
 }
 
 static int
@@ -853,6 +834,7 @@ int iser_reg_rdma_mem(struct iscsi_iser_task *task,
 	struct iser_device *device = ib_conn->device;
 	struct iser_data_buf *mem = &task->data[dir];
 	struct iser_mem_reg *reg = &task->rdma_reg[dir];
+	struct iser_mem_reg *data_reg;
 	struct iser_fr_desc *desc = NULL;
 	int err;
 
@@ -866,27 +848,31 @@ int iser_reg_rdma_mem(struct iscsi_iser_task *task,
 		reg->mem_h = desc;
 	}
 
-	err = iser_reg_data_sg(task, mem, desc, reg);
+	if (scsi_get_prot_op(task->sc) == SCSI_PROT_NORMAL)
+		data_reg = reg;
+	else
+		data_reg = &task->desc.data_reg;
+
+	err = iser_reg_data_sg(task, mem, desc, data_reg);
 	if (unlikely(err))
 		goto err_reg;
 
 	if (scsi_get_prot_op(task->sc) != SCSI_PROT_NORMAL) {
-		struct iser_mem_reg prot_reg;
+		struct iser_mem_reg *prot_reg = &task->desc.prot_reg;
 
-		memset(&prot_reg, 0, sizeof(prot_reg));
 		if (scsi_prot_sg_count(task->sc)) {
 			mem = &task->prot[dir];
 			err = iser_handle_unaligned_buf(task, mem, dir);
 			if (unlikely(err))
 				goto err_reg;
 
-			err = iser_reg_prot_sg(task, mem, desc, &prot_reg);
+			err = iser_reg_prot_sg(task, mem, desc, prot_reg);
 			if (unlikely(err))
 				goto err_reg;
 		}
 
-		err = iser_reg_sig_mr(task, desc->pi_ctx, reg,
-				      &prot_reg, reg);
+		err = iser_reg_sig_mr(task, desc->pi_ctx, data_reg,
+				      prot_reg, reg);
 		if (unlikely(err))
 			goto err_reg;