The DMA API debugging (when enabled) causes:
WARNING: CPU: 0 PID: 1445 at lib/dma-debug.c:519 add_dma_entry+0xe0/0x12c
DMA-API: exceeded 7 overlapping mappings of cacheline 0x01b2974d
to be printed after repeated initialization of the Ether device, e.g.
suspend/resume or 'ifconfig' up/down. This is because DMA buffers mapped
using dma_map_single() in sh_eth_ring_format() and sh_eth_start_xmit() are
never unmapped. Resolve this problem by unmapping the buffers when freeing
the descriptor rings; in order to do it right, we'd have to add an extra
parameter to sh_eth_txfree() (we rename this function to sh_eth_tx_free(),
while at it).
Based on the commit a47b70ea86bd ("ravb: unmap descriptors when freeing
rings").
Signed-off-by: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx>
---
This patch is against DaveM's 'net.git' repo.
Changed in version 2:
- fixed the "packet sent" condition in sh_eth_tx_free().
drivers/net/ethernet/renesas/sh_eth.c | 122 ++++++++++++++++++----------------
1 file changed, 67 insertions(+), 55 deletions(-)
Index: net/drivers/net/ethernet/renesas/sh_eth.c
===================================================================
--- net.orig/drivers/net/ethernet/renesas/sh_eth.c
+++ net/drivers/net/ethernet/renesas/sh_eth.c
@@ -1127,12 +1127,70 @@ static struct mdiobb_ops bb_ops = {
.get_mdio_data = sh_get_mdio,
};
+/* free Tx skb function */
+static int sh_eth_tx_free(struct net_device *ndev, bool sent_only)
+{
+ struct sh_eth_private *mdp = netdev_priv(ndev);
+ struct sh_eth_txdesc *txdesc;
+ int free_num = 0;
+ int entry;
+ bool sent;
+
+ for (; mdp->cur_tx - mdp->dirty_tx > 0; mdp->dirty_tx++) {
+ entry = mdp->dirty_tx % mdp->num_tx_ring;
+ txdesc = &mdp->tx_ring[entry];
+ sent = !(txdesc->status & cpu_to_le32(TD_TACT));
+ if (sent_only && !sent)
+ break;
+ /* TACT bit must be checked before all the following reads */
+ dma_rmb();
+ netif_info(mdp, tx_done, ndev,
+ "tx entry %d status 0x%08x\n",
+ entry, le32_to_cpu(txdesc->status));
+ /* Free the original skb. */
+ if (mdp->tx_skbuff[entry]) {
+ dma_unmap_single(&ndev->dev, le32_to_cpu(txdesc->addr),
+ le32_to_cpu(txdesc->len) >> 16,
+ DMA_TO_DEVICE);
+ dev_kfree_skb_irq(mdp->tx_skbuff[entry]);
+ mdp->tx_skbuff[entry] = NULL;
+ free_num++;
+ }
+ txdesc->status = cpu_to_le32(TD_TFP);
+ if (entry >= mdp->num_tx_ring - 1)
+ txdesc->status |= cpu_to_le32(TD_TDLE);
+
+ if (sent) {
+ ndev->stats.tx_packets++;
+ ndev->stats.tx_bytes += le32_to_cpu(txdesc->len) >> 16;
+ }
+ }
+ return free_num;
+}
+
/* free skb and descriptor buffer */
static void sh_eth_ring_free(struct net_device *ndev)
{
struct sh_eth_private *mdp = netdev_priv(ndev);
int ringsize, i;
+ if (mdp->rx_ring) {
+ for (i = 0; i < mdp->num_rx_ring; i++) {
+ if (mdp->rx_skbuff[i]) {
+ struct sh_eth_rxdesc *rxdesc = &mdp->rx_ring[i];
+
+ dma_unmap_single(&ndev->dev,
+ le32_to_cpu(rxdesc->addr),
+ ALIGN(mdp->rx_buf_sz, 32),
+ DMA_FROM_DEVICE);
+ }
+ }
+ ringsize = sizeof(struct sh_eth_rxdesc) * mdp->num_rx_ring;
+ dma_free_coherent(NULL, ringsize, mdp->rx_ring,
+ mdp->rx_desc_dma);
+ mdp->rx_ring = NULL;
+ }
+
/* Free Rx skb ringbuffer */
if (mdp->rx_skbuff) {
for (i = 0; i < mdp->num_rx_ring; i++)
@@ -1141,27 +1199,18 @@ static void sh_eth_ring_free(struct net_
kfree(mdp->rx_skbuff);
mdp->rx_skbuff = NULL;
- /* Free Tx skb ringbuffer */
- if (mdp->tx_skbuff) {
- for (i = 0; i < mdp->num_tx_ring; i++)
- dev_kfree_skb(mdp->tx_skbuff[i]);
- }
- kfree(mdp->tx_skbuff);
- mdp->tx_skbuff = NULL;
-
- if (mdp->rx_ring) {
- ringsize = sizeof(struct sh_eth_rxdesc) * mdp->num_rx_ring;
- dma_free_coherent(NULL, ringsize, mdp->rx_ring,
- mdp->rx_desc_dma);
- mdp->rx_ring = NULL;
- }
-
if (mdp->tx_ring) {
+ sh_eth_tx_free(ndev, false);
+
ringsize = sizeof(struct sh_eth_txdesc) * mdp->num_tx_ring;
dma_free_coherent(NULL, ringsize, mdp->tx_ring,
mdp->tx_desc_dma);
mdp->tx_ring = NULL;
}
+
+ /* Free Tx skb ringbuffer */
+ kfree(mdp->tx_skbuff);
+ mdp->tx_skbuff = NULL;
}
/* format skb and descriptor buffer */
@@ -1409,43 +1458,6 @@ static void sh_eth_dev_exit(struct net_d
update_mac_address(ndev);
}
-/* free Tx skb function */
-static int sh_eth_txfree(struct net_device *ndev)
-{
- struct sh_eth_private *mdp = netdev_priv(ndev);
- struct sh_eth_txdesc *txdesc;
- int free_num = 0;
- int entry;
-
- for (; mdp->cur_tx - mdp->dirty_tx > 0; mdp->dirty_tx++) {
- entry = mdp->dirty_tx % mdp->num_tx_ring;
- txdesc = &mdp->tx_ring[entry];
- if (txdesc->status & cpu_to_le32(TD_TACT))
- break;
- /* TACT bit must be checked before all the following reads */
- dma_rmb();
- netif_info(mdp, tx_done, ndev,
- "tx entry %d status 0x%08x\n",
- entry, le32_to_cpu(txdesc->status));
- /* Free the original skb. */
- if (mdp->tx_skbuff[entry]) {
- dma_unmap_single(&ndev->dev, le32_to_cpu(txdesc->addr),
- le32_to_cpu(txdesc->len) >> 16,
- DMA_TO_DEVICE);
- dev_kfree_skb_irq(mdp->tx_skbuff[entry]);
- mdp->tx_skbuff[entry] = NULL;
- free_num++;
- }
- txdesc->status = cpu_to_le32(TD_TFP);
- if (entry >= mdp->num_tx_ring - 1)
- txdesc->status |= cpu_to_le32(TD_TDLE);
-
- ndev->stats.tx_packets++;
- ndev->stats.tx_bytes += le32_to_cpu(txdesc->len) >> 16;
- }
- return free_num;
-}
-
/* Packet receive function */
static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
{
@@ -1690,7 +1702,7 @@ static void sh_eth_error(struct net_devi
intr_status, mdp->cur_tx, mdp->dirty_tx,
(u32)ndev->state, edtrr);
/* dirty buffer free */
- sh_eth_txfree(ndev);
+ sh_eth_tx_free(ndev, true);
/* SH7712 BUG */
if (edtrr ^ sh_eth_get_edtrr_trns(mdp)) {
@@ -1751,7 +1763,7 @@ static irqreturn_t sh_eth_interrupt(int
/* Clear Tx interrupts */
sh_eth_write(ndev, intr_status & cd->tx_check, EESR);
- sh_eth_txfree(ndev);
+ sh_eth_tx_free(ndev, true);
netif_wake_queue(ndev);
}
@@ -2412,7 +2424,7 @@ static int sh_eth_start_xmit(struct sk_b
spin_lock_irqsave(&mdp->lock, flags);
if ((mdp->cur_tx - mdp->dirty_tx) >= (mdp->num_tx_ring - 4)) {
- if (!sh_eth_txfree(ndev)) {
+ if (!sh_eth_tx_free(ndev, true)) {
netif_warn(mdp, tx_queued, ndev, "TxFD exhausted.\n");
netif_stop_queue(ndev);
spin_unlock_irqrestore(&mdp->lock, flags);
