ravb: unmap descriptors when freeing rings

"swiotlb buffer is full" errors occur after repeated initialisation of a
device - f.e. suspend/resume or ip link set up/down. This is because memory
mapped using dma_map_single() in ravb_ring_format() and ravb_start_xmit()
is not released.  Resolve this problem by unmapping descriptors when
freeing rings.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>
[simon: reworked]
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 89ac1e3..301f487 100644 (file)
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -179,6 +179,49 @@ static struct mdiobb_ops bb_ops = {
        .get_mdio_data = ravb_get_mdio_data,
 };
 
+/* Free TX skb function for AVB-IP */
+static int ravb_tx_free(struct net_device *ndev, int q, bool free_txed_only)
+{
+       struct ravb_private *priv = netdev_priv(ndev);
+       struct net_device_stats *stats = &priv->stats[q];
+       struct ravb_tx_desc *desc;
+       int free_num = 0;
+       int entry;
+       u32 size;
+
+       for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) {
+               bool txed;
+
+               entry = priv->dirty_tx[q] % (priv->num_tx_ring[q] *
+                                            NUM_TX_DESC);
+               desc = &priv->tx_ring[q][entry];
+               txed = desc->die_dt == DT_FEMPTY;
+               if (free_txed_only && !txed)
+                       break;
+               /* Descriptor type must be checked before all other reads */
+               dma_rmb();
+               size = le16_to_cpu(desc->ds_tagl) & TX_DS;
+               /* Free the original skb. */
+               if (priv->tx_skb[q][entry / NUM_TX_DESC]) {
+                       dma_unmap_single(ndev->dev.parent, le32_to_cpu(desc->dptr),
+                                        size, DMA_TO_DEVICE);
+                       /* Last packet descriptor? */
+                       if (entry % NUM_TX_DESC == NUM_TX_DESC - 1) {
+                               entry /= NUM_TX_DESC;
+                               dev_kfree_skb_any(priv->tx_skb[q][entry]);
+                               priv->tx_skb[q][entry] = NULL;
+                               if (txed)
+                                       stats->tx_packets++;
+                       }
+                       free_num++;
+               }
+               if (txed)
+                       stats->tx_bytes += size;
+               desc->die_dt = DT_EEMPTY;
+       }
+       return free_num;
+}
+
 /* Free skb's and DMA buffers for Ethernet AVB */
 static void ravb_ring_free(struct net_device *ndev, int q)
 {
@@ -194,19 +237,21 @@ static void ravb_ring_free(struct net_device *ndev, int q)
        kfree(priv->rx_skb[q]);
        priv->rx_skb[q] = NULL;
 
-       /* Free TX skb ringbuffer */
-       if (priv->tx_skb[q]) {
-               for (i = 0; i < priv->num_tx_ring[q]; i++)
-                       dev_kfree_skb(priv->tx_skb[q][i]);
-       }
-       kfree(priv->tx_skb[q]);
-       priv->tx_skb[q] = NULL;
-
        /* Free aligned TX buffers */
        kfree(priv->tx_align[q]);
        priv->tx_align[q] = NULL;
 
        if (priv->rx_ring[q]) {
+               for (i = 0; i < priv->num_rx_ring[q]; i++) {
+                       struct ravb_ex_rx_desc *desc = &priv->rx_ring[q][i];
+
+                       if (!dma_mapping_error(ndev->dev.parent,
+                                              le32_to_cpu(desc->dptr)))
+                               dma_unmap_single(ndev->dev.parent,
+                                                le32_to_cpu(desc->dptr),
+                                                PKT_BUF_SZ,
+                                                DMA_FROM_DEVICE);
+               }
                ring_size = sizeof(struct ravb_ex_rx_desc) *
                            (priv->num_rx_ring[q] + 1);
                dma_free_coherent(ndev->dev.parent, ring_size, priv->rx_ring[q],
@@ -215,12 +260,20 @@ static void ravb_ring_free(struct net_device *ndev, int q)
        }
 
        if (priv->tx_ring[q]) {
+               ravb_tx_free(ndev, q, false);
+
                ring_size = sizeof(struct ravb_tx_desc) *
                            (priv->num_tx_ring[q] * NUM_TX_DESC + 1);
                dma_free_coherent(ndev->dev.parent, ring_size, priv->tx_ring[q],
                                  priv->tx_desc_dma[q]);
                priv->tx_ring[q] = NULL;
        }
+
+       /* Free TX skb ringbuffer.
+        * SKBs are freed by ravb_tx_free() call above.
+        */
+       kfree(priv->tx_skb[q]);
+       priv->tx_skb[q] = NULL;
 }
 
 /* Format skb and descriptor buffer for Ethernet AVB */
@@ -431,44 +484,6 @@ static int ravb_dmac_init(struct net_device *ndev)
        return 0;
 }
 
-/* Free TX skb function for AVB-IP */
-static int ravb_tx_free(struct net_device *ndev, int q)
-{
-       struct ravb_private *priv = netdev_priv(ndev);
-       struct net_device_stats *stats = &priv->stats[q];
-       struct ravb_tx_desc *desc;
-       int free_num = 0;
-       int entry;
-       u32 size;
-
-       for (; priv->cur_tx[q] - priv->dirty_tx[q] > 0; priv->dirty_tx[q]++) {
-               entry = priv->dirty_tx[q] % (priv->num_tx_ring[q] *
-                                            NUM_TX_DESC);
-               desc = &priv->tx_ring[q][entry];
-               if (desc->die_dt != DT_FEMPTY)
-                       break;
-               /* Descriptor type must be checked before all other reads */
-               dma_rmb();
-               size = le16_to_cpu(desc->ds_tagl) & TX_DS;
-               /* Free the original skb. */
-               if (priv->tx_skb[q][entry / NUM_TX_DESC]) {
-                       dma_unmap_single(ndev->dev.parent, le32_to_cpu(desc->dptr),
-                                        size, DMA_TO_DEVICE);
-                       /* Last packet descriptor? */
-                       if (entry % NUM_TX_DESC == NUM_TX_DESC - 1) {
-                               entry /= NUM_TX_DESC;
-                               dev_kfree_skb_any(priv->tx_skb[q][entry]);
-                               priv->tx_skb[q][entry] = NULL;
-                               stats->tx_packets++;
-                       }
-                       free_num++;
-               }
-               stats->tx_bytes += size;
-               desc->die_dt = DT_EEMPTY;
-       }
-       return free_num;
-}
-
 static void ravb_get_tx_tstamp(struct net_device *ndev)
 {
        struct ravb_private *priv = netdev_priv(ndev);
@@ -902,7 +917,7 @@ static int ravb_poll(struct napi_struct *napi, int budget)
                        spin_lock_irqsave(&priv->lock, flags);
                        /* Clear TX interrupt */
                        ravb_write(ndev, ~mask, TIS);
-                       ravb_tx_free(ndev, q);
+                       ravb_tx_free(ndev, q, true);
                        netif_wake_subqueue(ndev, q);
                        mmiowb();
                        spin_unlock_irqrestore(&priv->lock, flags);
@@ -1567,7 +1582,8 @@ static netdev_tx_t ravb_start_xmit(struct sk_buff *skb, struct net_device *ndev)
 
        priv->cur_tx[q] += NUM_TX_DESC;
        if (priv->cur_tx[q] - priv->dirty_tx[q] >
-           (priv->num_tx_ring[q] - 1) * NUM_TX_DESC && !ravb_tx_free(ndev, q))
+           (priv->num_tx_ring[q] - 1) * NUM_TX_DESC &&
+           !ravb_tx_free(ndev, q, true))
                netif_stop_subqueue(ndev, q);
 
 exit: