IB/iser: Suppress completions for fast registration work requests

In case iSER uses fast registration method, it should not request for
successful completions on fast registration nor local invalidate
requests.  We color wr_id with ISER_FRWR_LI_WRID in order to correctly
consume error completions.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/ulp/iser/iscsi_iser.h

@@ -138,6 +138,8 @@
 #define ISER_WSV			0x08
 #define ISER_RSV			0x04
 
+#define ISER_FRWR_LI_WRID		0xffffffffffffffffULL
+
 struct iser_hdr {
 	u8      flags;
 	u8      rsvd[3];

drivers/infiniband/ulp/iser/iser_memory.c

@@ -457,8 +457,8 @@ static int iser_fast_reg_mr(struct fast_reg_descriptor *desc,
 
 	if (!desc->valid) {
 		memset(&inv_wr, 0, sizeof(inv_wr));
+		inv_wr.wr_id = ISER_FRWR_LI_WRID;
 		inv_wr.opcode = IB_WR_LOCAL_INV;
-		inv_wr.send_flags = IB_SEND_SIGNALED;
 		inv_wr.ex.invalidate_rkey = desc->data_mr->rkey;
 		wr = &inv_wr;
 		/* Bump the key */
@@ -468,8 +468,8 @@ static int iser_fast_reg_mr(struct fast_reg_descriptor *desc,
 
 	/* Prepare FASTREG WR */
 	memset(&fastreg_wr, 0, sizeof(fastreg_wr));
+	fastreg_wr.wr_id = ISER_FRWR_LI_WRID;
 	fastreg_wr.opcode = IB_WR_FAST_REG_MR;
-	fastreg_wr.send_flags = IB_SEND_SIGNALED;
 	fastreg_wr.wr.fast_reg.iova_start = desc->data_frpl->page_list[0] + offset;
 	fastreg_wr.wr.fast_reg.page_list = desc->data_frpl;
 	fastreg_wr.wr.fast_reg.page_list_len = page_list_len;
@@ -480,20 +480,13 @@ static int iser_fast_reg_mr(struct fast_reg_descriptor *desc,
 					       IB_ACCESS_REMOTE_WRITE |
 					       IB_ACCESS_REMOTE_READ);
 
-	if (!wr) {
+	if (!wr)
 		wr = &fastreg_wr;
-		atomic_inc(&ib_conn->post_send_buf_count);
-	} else {
+	else
 		wr->next = &fastreg_wr;
-		atomic_add(2, &ib_conn->post_send_buf_count);
-	}
 
 	ret = ib_post_send(ib_conn->qp, wr, &bad_wr);
 	if (ret) {
-		if (bad_wr->next)
-			atomic_sub(2, &ib_conn->post_send_buf_count);
-		else
-			atomic_dec(&ib_conn->post_send_buf_count);
 		iser_err("fast registration failed, ret:%d\n", ret);
 		return ret;
 	}

drivers/infiniband/ulp/iser/iser_verbs.c

@@ -993,18 +993,16 @@ static int iser_drain_tx_cq(struct iser_device  *device, int cq_index)
 		if (wc.status == IB_WC_SUCCESS) {
 			if (wc.opcode == IB_WC_SEND)
 				iser_snd_completion(tx_desc, ib_conn);
-			else if (wc.opcode == IB_WC_LOCAL_INV ||
-				 wc.opcode == IB_WC_FAST_REG_MR) {
-				atomic_dec(&ib_conn->post_send_buf_count);
-				continue;
-			} else
+			else
 				iser_err("expected opcode %d got %d\n",
 					IB_WC_SEND, wc.opcode);
 		} else {
 			iser_err("tx id %llx status %d vend_err %x\n",
-				wc.wr_id, wc.status, wc.vendor_err);
-			atomic_dec(&ib_conn->post_send_buf_count);
-			iser_handle_comp_error(tx_desc, ib_conn);
+				 wc.wr_id, wc.status, wc.vendor_err);
+			if (wc.wr_id != ISER_FRWR_LI_WRID) {
+				atomic_dec(&ib_conn->post_send_buf_count);
+				iser_handle_comp_error(tx_desc, ib_conn);
+			}
 		}
 		completed_tx++;
 	}