ravb: implement MTU change while device is up

Pre-allocates buffers sufficient for the maximum supported MTU (2026) in
order to eliminate the possibility of resource exhaustion when changing the
MTU while the device is up.

Signed-off-by: Ulrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index a9c89d5..9f88b5d 100644 (file)
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -955,6 +955,8 @@ enum RAVB_QUEUE {
 #define NUM_RX_QUEUE   2
 #define NUM_TX_QUEUE   2
 
+#define RX_BUF_SZ      (2048 - ETH_FCS_LEN + sizeof(__sum16))
+
 /* TX descriptors per packet */
 #define NUM_TX_DESC_GEN2       2
 #define NUM_TX_DESC_GEN3       1
@@ -1018,7 +1020,6 @@ struct ravb_private {
        u32 dirty_rx[NUM_RX_QUEUE];     /* Producer ring indices */
        u32 cur_tx[NUM_TX_QUEUE];
        u32 dirty_tx[NUM_TX_QUEUE];
-       u32 rx_buf_sz;                  /* Based on MTU+slack. */
        struct napi_struct napi[NUM_RX_QUEUE];
        struct work_struct work;
        /* MII transceiver section. */

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index de9aa8c..3f165c1 100644 (file)
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -230,7 +230,7 @@ static void ravb_ring_free(struct net_device *ndev, int q)
                                               le32_to_cpu(desc->dptr)))
                                dma_unmap_single(ndev->dev.parent,
                                                 le32_to_cpu(desc->dptr),
-                                                priv->rx_buf_sz,
+                                                RX_BUF_SZ,
                                                 DMA_FROM_DEVICE);
                }
                ring_size = sizeof(struct ravb_ex_rx_desc) *
@@ -293,9 +293,9 @@ static void ravb_ring_format(struct net_device *ndev, int q)
        for (i = 0; i < priv->num_rx_ring[q]; i++) {
                /* RX descriptor */
                rx_desc = &priv->rx_ring[q][i];
-               rx_desc->ds_cc = cpu_to_le16(priv->rx_buf_sz);
+               rx_desc->ds_cc = cpu_to_le16(RX_BUF_SZ);
                dma_addr = dma_map_single(ndev->dev.parent, priv->rx_skb[q][i]->data,
-                                         priv->rx_buf_sz,
+                                         RX_BUF_SZ,
                                          DMA_FROM_DEVICE);
                /* We just set the data size to 0 for a failed mapping which
                 * should prevent DMA from happening...
@@ -342,9 +342,6 @@ static int ravb_ring_init(struct net_device *ndev, int q)
        int ring_size;
        int i;
 
-       priv->rx_buf_sz = (ndev->mtu <= 1492 ? PKT_BUF_SZ : ndev->mtu) +
-               ETH_HLEN + VLAN_HLEN + sizeof(__sum16);
-
        /* Allocate RX and TX skb rings */
        priv->rx_skb[q] = kcalloc(priv->num_rx_ring[q],
                                  sizeof(*priv->rx_skb[q]), GFP_KERNEL);
@@ -354,7 +351,7 @@ static int ravb_ring_init(struct net_device *ndev, int q)
                goto error;
 
        for (i = 0; i < priv->num_rx_ring[q]; i++) {
-               skb = netdev_alloc_skb(ndev, priv->rx_buf_sz + RAVB_ALIGN - 1);
+               skb = netdev_alloc_skb(ndev, RX_BUF_SZ + RAVB_ALIGN - 1);
                if (!skb)
                        goto error;
                ravb_set_buffer_align(skb);
@@ -584,7 +581,7 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q)
                        skb = priv->rx_skb[q][entry];
                        priv->rx_skb[q][entry] = NULL;
                        dma_unmap_single(ndev->dev.parent, le32_to_cpu(desc->dptr),
-                                        priv->rx_buf_sz,
+                                        RX_BUF_SZ,
                                         DMA_FROM_DEVICE);
                        get_ts &= (q == RAVB_NC) ?
                                        RAVB_RXTSTAMP_TYPE_V2_L2_EVENT :
@@ -617,11 +614,11 @@ static bool ravb_rx(struct net_device *ndev, int *quota, int q)
        for (; priv->cur_rx[q] - priv->dirty_rx[q] > 0; priv->dirty_rx[q]++) {
                entry = priv->dirty_rx[q] % priv->num_rx_ring[q];
                desc = &priv->rx_ring[q][entry];
-               desc->ds_cc = cpu_to_le16(priv->rx_buf_sz);
+               desc->ds_cc = cpu_to_le16(RX_BUF_SZ);
 
                if (!priv->rx_skb[q][entry]) {
                        skb = netdev_alloc_skb(ndev,
-                                              priv->rx_buf_sz +
+                                              RX_BUF_SZ +
                                               RAVB_ALIGN - 1);
                        if (!skb)
                                break;  /* Better luck next round. */
@@ -1801,10 +1798,15 @@ static int ravb_do_ioctl(struct net_device *ndev, struct ifreq *req, int cmd)
 
 static int ravb_change_mtu(struct net_device *ndev, int new_mtu)
 {
-       if (netif_running(ndev))
-               return -EBUSY;
+       struct ravb_private *priv = netdev_priv(ndev);
 
        ndev->mtu = new_mtu;
+
+       if (netif_running(ndev)) {
+               synchronize_irq(priv->emac_irq);
+               ravb_emac_init(ndev);
+       }
+
        netdev_update_features(ndev);
 
        return 0;