This is a note to let you know that I've just added the patch titled sh_eth: unmap DMA buffers when freeing rings to the 4.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sh_eth-unmap-dma-buffers-when-freeing-rings.patch and it can be found in the queue-4.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sat Apr 29 08:22:40 CEST 2017 From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> Date: Mon, 17 Apr 2017 15:55:22 +0300 Subject: sh_eth: unmap DMA buffers when freeing rings From: Sergei Shtylyov <sergei.shtylyov@xxxxxxxxxxxxxxxxxx> [ Upstream commit 1debdc8f9ebd07daf140e417b3841596911e0066 ] 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> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/net/ethernet/renesas/sh_eth.c | 122 ++++++++++++++++++---------------- 1 file changed, 67 insertions(+), 55 deletions(-) --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -1061,12 +1061,70 @@ 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++) @@ -1075,27 +1133,18 @@ 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 */ @@ -1343,43 +1392,6 @@ 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) { @@ -1622,7 +1634,7 @@ ignore_link: 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)) { @@ -1681,7 +1693,7 @@ 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); } @@ -2309,7 +2321,7 @@ 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); Patches currently in stable-queue which might be from sergei.shtylyov@xxxxxxxxxxxxxxxxxx are queue-4.10/sh_eth-unmap-dma-buffers-when-freeing-rings.patch