ionic: change mtu without full queue rebuild

We really don't need to tear down and rebuild the whole queue structure
when changing the MTU; we can simply stop the queues, clean and refill,
then restart the queues.

Signed-off-by: Shannon Nelson <snelson@pensando.io>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/pensando/ionic/ionic_lif.c b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
index 2637eb8..176ffc1 100644 (file)
--- a/drivers/net/ethernet/pensando/ionic/ionic_lif.c
+++ b/drivers/net/ethernet/pensando/ionic/ionic_lif.c
@@ -36,6 +36,8 @@ static void ionic_lif_handle_fw_down(struct ionic_lif *lif);
 static void ionic_lif_handle_fw_up(struct ionic_lif *lif);
 static void ionic_lif_set_netdev_info(struct ionic_lif *lif);
 
+static void ionic_txrx_deinit(struct ionic_lif *lif);
+static int ionic_txrx_init(struct ionic_lif *lif);
 static int ionic_start_queues(struct ionic_lif *lif);
 static void ionic_stop_queues(struct ionic_lif *lif);
 static void ionic_lif_queue_identify(struct ionic_lif *lif);
@@ -593,6 +595,17 @@ err_out:
        return err;
 }
 
+static void ionic_qcq_sanitize(struct ionic_qcq *qcq)
+{
+       qcq->q.tail_idx = 0;
+       qcq->q.head_idx = 0;
+       qcq->cq.tail_idx = 0;
+       qcq->cq.done_color = 1;
+       memset(qcq->q_base, 0, qcq->q_size);
+       memset(qcq->cq_base, 0, qcq->cq_size);
+       memset(qcq->sg_base, 0, qcq->sg_size);
+}
+
 static int ionic_lif_txq_init(struct ionic_lif *lif, struct ionic_qcq *qcq)
 {
        struct device *dev = lif->ionic->dev;
@@ -632,9 +645,7 @@ static int ionic_lif_txq_init(struct ionic_lif *lif, struct ionic_qcq *qcq)
        dev_dbg(dev, "txq_init.ver %d\n", ctx.cmd.q_init.ver);
        dev_dbg(dev, "txq_init.intr_index %d\n", ctx.cmd.q_init.intr_index);
 
-       q->tail_idx = 0;
-       q->head_idx = 0;
-       cq->tail_idx = 0;
+       ionic_qcq_sanitize(qcq);
 
        err = ionic_adminq_post_wait(lif, &ctx);
        if (err)
@@ -689,9 +700,7 @@ static int ionic_lif_rxq_init(struct ionic_lif *lif, struct ionic_qcq *qcq)
        dev_dbg(dev, "rxq_init.ver %d\n", ctx.cmd.q_init.ver);
        dev_dbg(dev, "rxq_init.intr_index %d\n", ctx.cmd.q_init.intr_index);
 
-       q->tail_idx = 0;
-       q->head_idx = 0;
-       cq->tail_idx = 0;
+       ionic_qcq_sanitize(qcq);
 
        err = ionic_adminq_post_wait(lif, &ctx);
        if (err)
@@ -1307,6 +1316,35 @@ static int ionic_set_mac_address(struct net_device *netdev, void *sa)
        return ionic_addr_add(netdev, mac);
 }
 
+static void ionic_stop_queues_reconfig(struct ionic_lif *lif)
+{
+       /* Stop and clean the queues before reconfiguration */
+       mutex_lock(&lif->queue_lock);
+       netif_device_detach(lif->netdev);
+       ionic_stop_queues(lif);
+       ionic_txrx_deinit(lif);
+}
+
+static int ionic_start_queues_reconfig(struct ionic_lif *lif)
+{
+       int err;
+
+       /* Re-init the queues after reconfiguration */
+
+       /* The only way txrx_init can fail here is if communication
+        * with FW is suddenly broken.  There's not much we can do
+        * at this point - error messages have already been printed,
+        * so we can continue on and the user can eventually do a
+        * DOWN and UP to try to reset and clear the issue.
+        */
+       err = ionic_txrx_init(lif);
+       mutex_unlock(&lif->queue_lock);
+       ionic_link_status_check_request(lif);
+       netif_device_attach(lif->netdev);
+
+       return err;
+}
+
 static int ionic_change_mtu(struct net_device *netdev, int new_mtu)
 {
        struct ionic_lif *lif = netdev_priv(netdev);
@@ -1326,9 +1364,12 @@ static int ionic_change_mtu(struct net_device *netdev, int new_mtu)
                return err;
 
        netdev->mtu = new_mtu;
-       err = ionic_reset_queues(lif, NULL, NULL);
+       /* if we're not running, nothing more to do */
+       if (!netif_running(netdev))
+               return 0;
 
-       return err;
+       ionic_stop_queues_reconfig(lif);
+       return ionic_start_queues_reconfig(lif);
 }
 
 static void ionic_tx_timeout_work(struct work_struct *ws)