ehea: Fix DLPAR memory add support

This patch fixes two weaknesses in send/receive packet handling which may
lead to kernel panics during DLPAR memory add operations.
Signed-off-by: Thomas Klein <tklein@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

drivers/net/ehea/ehea.h

@@ -40,7 +40,7 @@
 #include <asm/io.h>
 
 #define DRV_NAME	"ehea"
-#define DRV_VERSION	"EHEA_0089"
+#define DRV_VERSION	"EHEA_0090"
 
 /* eHEA capability flags */
 #define DLPAR_PORT_ADD_REM 1
@@ -371,6 +371,7 @@ struct ehea_port_res {
 	struct ehea_q_skb_arr rq2_skba;
 	struct ehea_q_skb_arr rq3_skba;
 	struct ehea_q_skb_arr sq_skba;
+	int sq_skba_size;
 	spinlock_t netif_queue;
 	int queue_stopped;
 	int swqe_refill_th;

drivers/net/ehea/ehea_main.c

@@ -349,7 +349,8 @@ static void ehea_refill_rq1(struct ehea_port_res *pr, int index, int nr_of_wqes)
 	pr->rq1_skba.os_skbs = 0;
 
 	if (unlikely(test_bit(__EHEA_STOP_XFER, &ehea_driver_flags))) {
-		pr->rq1_skba.index = index;
+		if (nr_of_wqes > 0)
+			pr->rq1_skba.index = index;
 		pr->rq1_skba.os_skbs = fill_wqes;
 		return;
 	}
@@ -1464,7 +1465,9 @@ static int ehea_init_port_res(struct ehea_port *port, struct ehea_port_res *pr,
 			  init_attr->act_nr_rwqes_rq2,
 			  init_attr->act_nr_rwqes_rq3);
 
-	ret = ehea_init_q_skba(&pr->sq_skba, init_attr->act_nr_send_wqes + 1);
+	pr->sq_skba_size = init_attr->act_nr_send_wqes + 1;
+
+	ret = ehea_init_q_skba(&pr->sq_skba, pr->sq_skba_size);
 	ret |= ehea_init_q_skba(&pr->rq1_skba, init_attr->act_nr_rwqes_rq1 + 1);
 	ret |= ehea_init_q_skba(&pr->rq2_skba, init_attr->act_nr_rwqes_rq2 + 1);
 	ret |= ehea_init_q_skba(&pr->rq3_skba, init_attr->act_nr_rwqes_rq3 + 1);
@@ -2621,6 +2624,22 @@ void ehea_purge_sq(struct ehea_qp *orig_qp)
 	}
 }
 
+void ehea_flush_sq(struct ehea_port *port)
+{
+	int i;
+
+	for (i = 0; i < port->num_def_qps + port->num_add_tx_qps; i++) {
+		struct ehea_port_res *pr = &port->port_res[i];
+		int swqe_max = pr->sq_skba_size - 2 - pr->swqe_ll_count;
+		int k = 0;
+		while (atomic_read(&pr->swqe_avail) < swqe_max) {
+			msleep(5);
+			if (++k == 20)
+				break;
+		}
+	}
+}
+
 int ehea_stop_qps(struct net_device *dev)
 {
 	struct ehea_port *port = netdev_priv(dev);
@@ -2845,6 +2864,7 @@ static void ehea_rereg_mrs(struct work_struct *work)
 					if (dev->flags & IFF_UP) {
 						down(&port->port_lock);
 						netif_stop_queue(dev);
+						ehea_flush_sq(port);
 						ret = ehea_stop_qps(dev);
 						if (ret) {
 							up(&port->port_lock);