ehea: Remove sleep at .ndo_get_stats

Currently ehea ndo_get_stats can sleep in two places, in a hcall
and in a GFP_KERNEL alloc, which is not correct.
This patch creates a delayed workqueue that grabs the information each 1
sec from the hardware, and place it into the device structure, so that,
.ndo_get_stats quickly returns the device structure statistics block.

Signed-off-by: Breno Leitao <brenohl@br.ibm.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 36 insertions, 23 deletions

diff --git a/drivers/net/ethernet/ibm/ehea/ehea_main.c b/drivers/net/ethernet/ibm/ehea/ehea_main.c
index 583bcd32e543..c821cb653999 100644
--- a/drivers/net/ethernet/ibm/ehea/ehea_main.c
+++ b/drivers/net/ethernet/ibm/ehea/ehea_main.c
@@ -331,16 +331,40 @@ static struct net_device_stats *ehea_get_stats(struct net_device *dev)
 {
         struct ehea_port *port = netdev_priv(dev);
         struct net_device_stats *stats = &port->stats;
-        struct hcp_ehea_port_cb2 *cb2;
-        u64 hret, rx_packets, tx_packets, rx_bytes = 0, tx_bytes = 0;
+        u64 rx_packets = 0, tx_packets = 0, rx_bytes = 0, tx_bytes = 0;
         int i;
 
-        memset(stats, 0, sizeof(*stats));
+        for (i = 0; i < port->num_def_qps; i++) {
+                rx_packets += port->port_res[i].rx_packets;
+                rx_bytes   += port->port_res[i].rx_bytes;
+        }
+
+        for (i = 0; i < port->num_def_qps + port->num_add_tx_qps; i++) {
+                tx_packets += port->port_res[i].tx_packets;
+                tx_bytes   += port->port_res[i].tx_bytes;
+        }
+
+        stats->tx_packets = tx_packets;
+        stats->rx_bytes = rx_bytes;
+        stats->tx_bytes = tx_bytes;
+        stats->rx_packets = rx_packets;
+
+        return &port->stats;
+}
+
+static void ehea_update_stats(struct work_struct *work)
+{
+        struct ehea_port *port =
+                container_of(work, struct ehea_port, stats_work.work);
+        struct net_device *dev = port->netdev;
+        struct net_device_stats *stats = &port->stats;
+        struct hcp_ehea_port_cb2 *cb2;
+        u64 hret;
 
         cb2 = (void *)get_zeroed_page(GFP_KERNEL);
         if (!cb2) {
-                netdev_err(dev, "no mem for cb2\n");
-                goto out;
+                netdev_err(dev, "No mem for cb2. Some interface statistics were not updated\n");
+                goto resched;
         }
 
         hret = ehea_h_query_ehea_port(port->adapter->handle,
@@ -354,29 +378,13 @@ static struct net_device_stats *ehea_get_stats(struct net_device *dev)
         if (netif_msg_hw(port))
                 ehea_dump(cb2, sizeof(*cb2), "net_device_stats");
 
-        rx_packets = 0;
-        for (i = 0; i < port->num_def_qps; i++) {
-                rx_packets += port->port_res[i].rx_packets;
-                rx_bytes   += port->port_res[i].rx_bytes;
-        }
-
-        tx_packets = 0;
-        for (i = 0; i < port->num_def_qps + port->num_add_tx_qps; i++) {
-                tx_packets += port->port_res[i].tx_packets;
-                tx_bytes   += port->port_res[i].tx_bytes;
-        }
-
-        stats->tx_packets = tx_packets;
         stats->multicast = cb2->rxmcp;
         stats->rx_errors = cb2->rxuerr;
-        stats->rx_bytes = rx_bytes;
-        stats->tx_bytes = tx_bytes;
-        stats->rx_packets = rx_packets;
 
 out_herr:
         free_page((unsigned long)cb2);
-out:
-        return stats;
+resched:
+        schedule_delayed_work(&port->stats_work, msecs_to_jiffies(1000));
 }
 
 static void ehea_refill_rq1(struct ehea_port_res *pr, int index, int nr_of_wqes)
@@ -2651,6 +2659,7 @@ static int ehea_open(struct net_device *dev)
         }
 
         mutex_unlock(&port->port_lock);
+        schedule_delayed_work(&port->stats_work, msecs_to_jiffies(1000));
 
         return ret;
 }
@@ -2690,6 +2699,7 @@ static int ehea_stop(struct net_device *dev)
 
         set_bit(__EHEA_DISABLE_PORT_RESET, &port->flags);
         cancel_work_sync(&port->reset_task);
+        cancel_delayed_work_sync(&port->stats_work);
         mutex_lock(&port->port_lock);
         netif_stop_queue(dev);
         port_napi_disable(port);
@@ -3235,10 +3245,12 @@ struct ehea_port *ehea_setup_single_port(struct ehea_adapter *adapter,
                 dev->features |= NETIF_F_LRO;
 
         INIT_WORK(&port->reset_task, ehea_reset_port);
+        INIT_DELAYED_WORK(&port->stats_work, ehea_update_stats);
 
         init_waitqueue_head(&port->swqe_avail_wq);
         init_waitqueue_head(&port->restart_wq);
 
+        memset(&port->stats, 0, sizeof(struct net_device_stats));
         ret = register_netdev(dev);
         if (ret) {
                 pr_err("register_netdev failed. ret=%d\n", ret);
@@ -3278,6 +3290,7 @@ static void ehea_shutdown_single_port(struct ehea_port *port)
         struct ehea_adapter *adapter = port->adapter;
 
         cancel_work_sync(&port->reset_task);
+        cancel_delayed_work_sync(&port->stats_work);
         unregister_netdev(port->netdev);
         ehea_unregister_port(port);
         kfree(port->mc_list);