[PATCH 4.9 065/108] ravb: unmap descriptors when freeing rings

Greg Kroah-Hartman
2017-06-15T17:59:13Z

From: Kazuya Mizuguchi <kazuya.mizuguchi.ks@renesas.com>

[ Upstream commit a47b70ea86bdeb3091341f5ae3ef580f1a1ad822 ]

"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>

Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/ethernet/renesas/ravb_main.c | 112 +++++++++++++++++--------------
1 file changed, 64 insertions(+), 48 deletions(-)

--- 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_de
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_de
}

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_dev
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
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);
@@ -1571,7 +1586,8 @@ static netdev_tx_t ravb_start_xmit(struc

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);