scsi: iscsi: Rel ref after iscsi_lookup_endpoint()

Subsequent commits allow the kernel to do ep_disconnect. In that case we
will have to get a proper refcount on the ep so one thread does not delete
it from under another.

Link: https://lore.kernel.org/r/20210525181821.7617-7-michael.christie@oracle.com
Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: Mike Christie <michael.christie@oracle.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/infiniband/ulp/iser/iscsi_iser.c

@@ -506,6 +506,7 @@ iscsi_iser_conn_bind(struct iscsi_cls_session *cls_session,
 	iser_conn->iscsi_conn = conn;
 
 out:
+	iscsi_put_endpoint(ep);
 	mutex_unlock(&iser_conn->state_mutex);
 	return error;
 }

drivers/scsi/be2iscsi/be_iscsi.c

@@ -182,22 +182,25 @@ int beiscsi_conn_bind(struct iscsi_cls_session *cls_session,
 	struct beiscsi_endpoint *beiscsi_ep;
 	struct iscsi_endpoint *ep;
 	uint16_t cri_index;
+	int rc = 0;
 
 	ep = iscsi_lookup_endpoint(transport_fd);
 	if (!ep)
 		return -EINVAL;
 
 	beiscsi_ep = ep->dd_data;
 
-	if (iscsi_conn_bind(cls_session, cls_conn, is_leading))
-		return -EINVAL;
+	if (iscsi_conn_bind(cls_session, cls_conn, is_leading)) {
+		rc = -EINVAL;
+		goto put_ep;
+	}
 
 	if (beiscsi_ep->phba != phba) {
 		beiscsi_log(phba, KERN_ERR, BEISCSI_LOG_CONFIG,
 			    "BS_%d : beiscsi_ep->hba=%p not equal to phba=%p\n",
 			    beiscsi_ep->phba, phba);
-
-		return -EEXIST;
+		rc = -EEXIST;
+		goto put_ep;
 	}
 	cri_index = BE_GET_CRI_FROM_CID(beiscsi_ep->ep_cid);
 	if (phba->conn_table[cri_index]) {
@@ -209,7 +212,8 @@ int beiscsi_conn_bind(struct iscsi_cls_session *cls_session,
 				      beiscsi_ep->ep_cid,
 				      beiscsi_conn,
 				      phba->conn_table[cri_index]);
-			return -EINVAL;
+			rc = -EINVAL;
+			goto put_ep;
 		}
 	}
 
@@ -226,7 +230,10 @@ int beiscsi_conn_bind(struct iscsi_cls_session *cls_session,
 		    "BS_%d : cid %d phba->conn_table[%u]=%p\n",
 		    beiscsi_ep->ep_cid, cri_index, beiscsi_conn);
 	phba->conn_table[cri_index] = beiscsi_conn;
-	return 0;
+
+put_ep:
+	iscsi_put_endpoint(ep);
+	return rc;
 }
 
 static int beiscsi_iface_create_ipv4(struct beiscsi_hba *phba)

drivers/scsi/bnx2i/bnx2i_iscsi.c

@@ -1420,17 +1420,23 @@ static int bnx2i_conn_bind(struct iscsi_cls_session *cls_session,
 	 * Forcefully terminate all in progress connection recovery at the
 	 * earliest, either in bind(), send_pdu(LOGIN), or conn_start()
 	 */
-	if (bnx2i_adapter_ready(hba))
-		return -EIO;
+	if (bnx2i_adapter_ready(hba)) {
+		ret_code = -EIO;
+		goto put_ep;
+	}
 
 	bnx2i_ep = ep->dd_data;
 	if ((bnx2i_ep->state == EP_STATE_TCP_FIN_RCVD) ||
-	    (bnx2i_ep->state == EP_STATE_TCP_RST_RCVD))
+	    (bnx2i_ep->state == EP_STATE_TCP_RST_RCVD)) {
 		/* Peer disconnect via' FIN or RST */
-		return -EINVAL;
+		ret_code = -EINVAL;
+		goto put_ep;
+	}
 
-	if (iscsi_conn_bind(cls_session, cls_conn, is_leading))
-		return -EINVAL;
+	if (iscsi_conn_bind(cls_session, cls_conn, is_leading)) {
+		ret_code = -EINVAL;
+		goto put_ep;
+	}
 
 	if (bnx2i_ep->hba != hba) {
 		/* Error - TCP connection does not belong to this device
@@ -1441,7 +1447,8 @@ static int bnx2i_conn_bind(struct iscsi_cls_session *cls_session,
 		iscsi_conn_printk(KERN_ALERT, cls_conn->dd_data,
 				  "belong to hba (%s)\n",
 				  hba->netdev->name);
-		return -EEXIST;
+		ret_code = -EEXIST;
+		goto put_ep;
 	}
 	bnx2i_ep->conn = bnx2i_conn;
 	bnx2i_conn->ep = bnx2i_ep;
@@ -1458,6 +1465,8 @@ static int bnx2i_conn_bind(struct iscsi_cls_session *cls_session,
 		bnx2i_put_rq_buf(bnx2i_conn, 0);
 
 	bnx2i_arm_cq_event_coalescing(bnx2i_conn->ep, CNIC_ARM_CQE);
+put_ep:
+	iscsi_put_endpoint(ep);
 	return ret_code;
 }
 

drivers/scsi/cxgbi/libcxgbi.c

@@ -2690,11 +2690,13 @@ int cxgbi_bind_conn(struct iscsi_cls_session *cls_session,
 	err = csk->cdev->csk_ddp_setup_pgidx(csk, csk->tid,
 					     ppm->tformat.pgsz_idx_dflt);
 	if (err < 0)
-		return err;
+		goto put_ep;
 
 	err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
-	if (err)
-		return -EINVAL;
+	if (err) {
+		err = -EINVAL;
+		goto put_ep;
+	}
 
 	/*  calculate the tag idx bits needed for this conn based on cmds_max */
 	cconn->task_idx_bits = (__ilog2_u32(conn->session->cmds_max - 1)) + 1;
@@ -2715,7 +2717,9 @@ int cxgbi_bind_conn(struct iscsi_cls_session *cls_session,
 	/*  init recv engine */
 	iscsi_tcp_hdr_recv_prep(tcp_conn);
 
-	return 0;
+put_ep:
+	iscsi_put_endpoint(ep);
+	return err;
 }
 EXPORT_SYMBOL_GPL(cxgbi_bind_conn);
 

drivers/scsi/qedi/qedi_iscsi.c

@@ -377,18 +377,24 @@ static int qedi_conn_bind(struct iscsi_cls_session *cls_session,
 	struct qedi_ctx *qedi = iscsi_host_priv(shost);
 	struct qedi_endpoint *qedi_ep;
 	struct iscsi_endpoint *ep;
+	int rc = 0;
 
 	ep = iscsi_lookup_endpoint(transport_fd);
 	if (!ep)
 		return -EINVAL;
 
 	qedi_ep = ep->dd_data;
 	if ((qedi_ep->state == EP_STATE_TCP_FIN_RCVD) ||
-	    (qedi_ep->state == EP_STATE_TCP_RST_RCVD))
-		return -EINVAL;
+	    (qedi_ep->state == EP_STATE_TCP_RST_RCVD)) {
+		rc = -EINVAL;
+		goto put_ep;
+	}
+
+	if (iscsi_conn_bind(cls_session, cls_conn, is_leading)) {
+		rc = -EINVAL;
+		goto put_ep;
+	}
 
-	if (iscsi_conn_bind(cls_session, cls_conn, is_leading))
-		return -EINVAL;
 
 	qedi_ep->conn = qedi_conn;
 	qedi_conn->ep = qedi_ep;
@@ -398,13 +404,18 @@ static int qedi_conn_bind(struct iscsi_cls_session *cls_session,
 	qedi_conn->cmd_cleanup_req = 0;
 	qedi_conn->cmd_cleanup_cmpl = 0;
 
-	if (qedi_bind_conn_to_iscsi_cid(qedi, qedi_conn))
-		return -EINVAL;
+	if (qedi_bind_conn_to_iscsi_cid(qedi, qedi_conn)) {
+		rc = -EINVAL;
+		goto put_ep;
+	}
+
 
 	spin_lock_init(&qedi_conn->tmf_work_lock);
 	INIT_LIST_HEAD(&qedi_conn->tmf_work_list);
 	init_waitqueue_head(&qedi_conn->wait_queue);
-	return 0;
+put_ep:
+	iscsi_put_endpoint(ep);
+	return rc;
 }
 
 static int qedi_iscsi_update_conn(struct qedi_ctx *qedi,

drivers/scsi/qla4xxx/ql4_os.c

@@ -3235,6 +3235,7 @@ static int qla4xxx_conn_bind(struct iscsi_cls_session *cls_session,
 	conn = cls_conn->dd_data;
 	qla_conn = conn->dd_data;
 	qla_conn->qla_ep = ep->dd_data;
+	iscsi_put_endpoint(ep);
 	return 0;
 }
 

drivers/scsi/scsi_transport_iscsi.c

@@ -266,23 +266,28 @@ void iscsi_destroy_endpoint(struct iscsi_endpoint *ep)
 }
 EXPORT_SYMBOL_GPL(iscsi_destroy_endpoint);
 
+void iscsi_put_endpoint(struct iscsi_endpoint *ep)
+{
+	put_device(&ep->dev);
+}
+EXPORT_SYMBOL_GPL(iscsi_put_endpoint);
+
+/**
+ * iscsi_lookup_endpoint - get ep from handle
+ * @handle: endpoint handle
+ *
+ * Caller must do a iscsi_put_endpoint.
+ */
 struct iscsi_endpoint *iscsi_lookup_endpoint(u64 handle)
 {
-	struct iscsi_endpoint *ep;
 	struct device *dev;
 
 	dev = class_find_device(&iscsi_endpoint_class, NULL, &handle,
 				iscsi_match_epid);
 	if (!dev)
 		return NULL;
 
-	ep = iscsi_dev_to_endpoint(dev);
-	/*
-	 * we can drop this now because the interface will prevent
-	 * removals and lookups from racing.
-	 */
-	put_device(dev);
-	return ep;
+	return iscsi_dev_to_endpoint(dev);
 }
 EXPORT_SYMBOL_GPL(iscsi_lookup_endpoint);
 
@@ -2990,6 +2995,7 @@ static int iscsi_if_ep_disconnect(struct iscsi_transport *transport,
 	}
 
 	transport->ep_disconnect(ep);
+	iscsi_put_endpoint(ep);
 	return 0;
 }
 
@@ -3015,6 +3021,7 @@ iscsi_if_transport_ep(struct iscsi_transport *transport,
 
 		ev->r.retcode = transport->ep_poll(ep,
 						   ev->u.ep_poll.timeout_ms);
+		iscsi_put_endpoint(ep);
 		break;
 	case ISCSI_UEVENT_TRANSPORT_EP_DISCONNECT:
 		rc = iscsi_if_ep_disconnect(transport,
@@ -3698,6 +3705,7 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
 					ev->u.c_bound_session.initial_cmdsn,
 					ev->u.c_bound_session.cmds_max,
 					ev->u.c_bound_session.queue_depth);
+		iscsi_put_endpoint(ep);
 		break;
 	case ISCSI_UEVENT_DESTROY_SESSION:
 		session = iscsi_session_lookup(ev->u.d_session.sid);
@@ -3769,6 +3777,7 @@ iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
 			mutex_lock(&conn->ep_mutex);
 			conn->ep = ep;
 			mutex_unlock(&conn->ep_mutex);
+			iscsi_put_endpoint(ep);
 		} else
 			iscsi_cls_conn_printk(KERN_ERR, conn,
 					      "Could not set ep conn "

include/scsi/scsi_transport_iscsi.h

@@ -442,6 +442,7 @@ extern int iscsi_scan_finished(struct Scsi_Host *shost, unsigned long time);
 extern struct iscsi_endpoint *iscsi_create_endpoint(int dd_size);
 extern void iscsi_destroy_endpoint(struct iscsi_endpoint *ep);
 extern struct iscsi_endpoint *iscsi_lookup_endpoint(u64 handle);
+extern void iscsi_put_endpoint(struct iscsi_endpoint *ep);
 extern int iscsi_block_scsi_eh(struct scsi_cmnd *cmd);
 extern struct iscsi_iface *iscsi_create_iface(struct Scsi_Host *shost,
 					      struct iscsi_transport *t,