IB/iser: Signal iSCSI layer that transport is broken in error completions

Previously we notified iscsi layer about the connection layer when
we consumed all of our flush errors. This was racy as there
was no guarentee that iscsi_conn wasn't terminated by then (which ends
up in an invalid memory access). In case we got a non FLUSH error
completion, we are guarenteed that iscsi_conn is still alive. We should
notify iSCSI layer with iscsi_conn_failure to initiate error handling.

While we are at it, add a nice kernel-doc style documentation.
Signed-off-by: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Ariel Nahum <arieln@mellanox.com>
Signed-off-by: Roi Dayan <roid@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/ulp/iser/iser_verbs.c

@@ -1159,9 +1159,30 @@ int iser_post_send(struct ib_conn *ib_conn, struct iser_tx_desc *tx_desc)
 	return ib_ret;
 }
 
-static void iser_handle_comp_error(struct iser_tx_desc *desc,
-				   struct ib_conn *ib_conn)
+/**
+ * iser_handle_comp_error() - Handle error completion
+ * @desc:      iser TX descriptor
+ * @ib_conn:   connection RDMA resources
+ * @wc:        work completion
+ *
+ * Notes: We may handle a FLUSH error completion and in this case
+ *        we only cleanup in case TX type was DATAOUT. For non-FLUSH
+ *        error completion we should also notify iscsi layer that
+ *        connection is failed (in case we passed bind stage).
+ */
+static void
+iser_handle_comp_error(struct iser_tx_desc *desc,
+		       struct ib_conn *ib_conn,
+		       struct ib_wc *wc)
 {
+	struct iser_conn *iser_conn = container_of(ib_conn, struct iser_conn,
+						   ib_conn);
+
+	if (wc->status != IB_WC_WR_FLUSH_ERR)
+		if (iser_conn->iscsi_conn)
+			iscsi_conn_failure(iser_conn->iscsi_conn,
+					   ISCSI_ERR_CONN_FAILED);
+
 	if (desc && desc->type == ISCSI_TX_DATAOUT)
 		kmem_cache_free(ig.desc_cache, desc);
 }
@@ -1188,7 +1209,7 @@ static int iser_drain_tx_cq(struct iser_device  *device, int cq_index)
 				 wc.wr_id, wc.status, wc.vendor_err);
 			if (wc.wr_id != ISER_FASTREG_LI_WRID) {
 				atomic_dec(&ib_conn->post_send_buf_count);
-				iser_handle_comp_error(tx_desc, ib_conn);
+				iser_handle_comp_error(tx_desc, ib_conn, &wc);
 			}
 		}
 		completed_tx++;
@@ -1230,7 +1251,7 @@ static void iser_cq_tasklet_fn(unsigned long data)
 				iser_err("rx id %llx status %d vend_err %x\n",
 					wc.wr_id, wc.status, wc.vendor_err);
 			ib_conn->post_recv_buf_count--;
-			iser_handle_comp_error(NULL, ib_conn);
+			iser_handle_comp_error(NULL, ib_conn, &wc);
 		}
 		completed_rx++;
 		if (!(completed_rx & 63))