| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <550237CD.3060408@gmail.com>
Date: Thu, 12 Mar 2015 18:05:17 -0700
From: Florian Fainelli <f.fainelli@...il.com>
To: Petri Gynther <pgynther@...gle.com>, netdev@...r.kernel.org
CC: davem@...emloft.net, jaedon.shin@...il.com
Subject: Re: [PATCH net-next] net: bcmgenet: rewrite bcmgenet_rx_refill()
On 12/03/15 15:48, Petri Gynther wrote:
> Currently, bcmgenet_desc_rx() calls bcmgenet_rx_refill() at the end of
> Rx packet processing loop, after the current Rx packet has already been
> passed to napi_gro_receive(). However, bcmgenet_rx_refill() might fail
> to allocate a new Rx skb, thus leaving a hole on the Rx queue where no
> valid Rx buffer exists.
>
> To eliminate this situation:
> 1. Rewrite bcmgenet_rx_refill() to retain the current Rx skb on the Rx
> queue if a new replacement Rx skb can't be allocated and DMA-mapped.
> In this case, the data on the current Rx skb is effectively dropped.
> 2. Modify bcmgenet_desc_rx() to call bcmgenet_rx_refill() at the top of
> Rx packet processing loop, so that the new replacement Rx skb is
> already in place before the current Rx skb is processed.
This looks good at first glance, I will give this a try and report back,
thanks!
>
> Signed-off-by: Petri Gynther <pgynther@...gle.com>
> ---
> drivers/net/ethernet/broadcom/genet/bcmgenet.c | 99 +++++++++++---------------
> 1 file changed, 43 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> index d3be1aeb..875967e 100644
> --- a/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> +++ b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
> @@ -1336,36 +1336,47 @@ out:
> return ret;
> }
>
> -
> -static int bcmgenet_rx_refill(struct bcmgenet_priv *priv, struct enet_cb *cb)
> +static struct sk_buff *bcmgenet_rx_refill(struct bcmgenet_priv *priv,
> + struct enet_cb *cb)
> {
> struct device *kdev = &priv->pdev->dev;
> struct sk_buff *skb;
> + struct sk_buff *rx_skb;
> dma_addr_t mapping;
> - int ret;
>
> + /* Allocate a new Rx skb */
> skb = netdev_alloc_skb(priv->dev, priv->rx_buf_len + SKB_ALIGNMENT);
> - if (!skb)
> - return -ENOMEM;
> + if (!skb) {
> + priv->mib.alloc_rx_buff_failed++;
> + netif_err(priv, rx_err, priv->dev,
> + "%s: Rx skb allocation failed\n", __func__);
> + return NULL;
> + }
>
> - /* a caller did not release this control block */
> - WARN_ON(cb->skb != NULL);
> - cb->skb = skb;
> - mapping = dma_map_single(kdev, skb->data,
> - priv->rx_buf_len, DMA_FROM_DEVICE);
> - ret = dma_mapping_error(kdev, mapping);
> - if (ret) {
> + /* DMA-map the new Rx skb */
> + mapping = dma_map_single(kdev, skb->data, priv->rx_buf_len,
> + DMA_FROM_DEVICE);
> + if (dma_mapping_error(kdev, mapping)) {
> priv->mib.rx_dma_failed++;
> - bcmgenet_free_cb(cb);
> + dev_kfree_skb_any(skb);
> netif_err(priv, rx_err, priv->dev,
> - "%s DMA map failed\n", __func__);
> - return ret;
> + "%s: Rx skb DMA mapping failed\n", __func__);
> + return NULL;
> }
>
> + /* Grab the current Rx skb from the ring and DMA-unmap it */
> + rx_skb = cb->skb;
> + if (likely(rx_skb))
> + dma_unmap_single(kdev, dma_unmap_addr(cb, dma_addr),
> + priv->rx_buf_len, DMA_FROM_DEVICE);
> +
> + /* Put the new Rx skb on the ring */
> + cb->skb = skb;
> dma_unmap_addr_set(cb, dma_addr, mapping);
> dmadesc_set_addr(priv, cb->bd_addr, mapping);
>
> - return 0;
> + /* Return the current Rx skb to caller */
> + return rx_skb;
> }
>
> /* bcmgenet_desc_rx - descriptor based rx process.
> @@ -1381,7 +1392,7 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv,
> struct sk_buff *skb;
> u32 dma_length_status;
> unsigned long dma_flag;
> - int len, err;
> + int len;
> unsigned int rxpktprocessed = 0, rxpkttoprocess;
> unsigned int p_index;
> unsigned int discards;
> @@ -1419,26 +1430,14 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv,
> while ((rxpktprocessed < rxpkttoprocess) &&
> (rxpktprocessed < budget)) {
> cb = &priv->rx_cbs[ring->read_ptr];
> - skb = cb->skb;
> + skb = bcmgenet_rx_refill(priv, cb);
>
> - /* We do not have a backing SKB, so we do not have a
> - * corresponding DMA mapping for this incoming packet since
> - * bcmgenet_rx_refill always either has both skb and mapping or
> - * none.
> - */
> if (unlikely(!skb)) {
> dev->stats.rx_dropped++;
> dev->stats.rx_errors++;
> - goto refill;
> + goto next;
> }
>
> - /* Unmap the packet contents such that we can use the
> - * RSV from the 64 bytes descriptor when enabled and save
> - * a 32-bits register read
> - */
> - dma_unmap_single(&dev->dev, dma_unmap_addr(cb, dma_addr),
> - priv->rx_buf_len, DMA_FROM_DEVICE);
> -
> if (!priv->desc_64b_en) {
> dma_length_status =
> dmadesc_get_length_status(priv, cb->bd_addr);
> @@ -1465,10 +1464,10 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv,
> "dropping fragmented packet!\n");
> dev->stats.rx_dropped++;
> dev->stats.rx_errors++;
> - dev_kfree_skb_any(cb->skb);
> - cb->skb = NULL;
> - goto refill;
> + dev_kfree_skb_any(skb);
> + goto next;
> }
> +
> /* report errors */
> if (unlikely(dma_flag & (DMA_RX_CRC_ERROR |
> DMA_RX_OV |
> @@ -1487,11 +1486,8 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv,
> dev->stats.rx_length_errors++;
> dev->stats.rx_dropped++;
> dev->stats.rx_errors++;
> -
> - /* discard the packet and advance consumer index.*/
> - dev_kfree_skb_any(cb->skb);
> - cb->skb = NULL;
> - goto refill;
> + dev_kfree_skb_any(skb);
> + goto next;
> } /* error packet */
>
> chksum_ok = (dma_flag & priv->dma_rx_chk_bit) &&
> @@ -1524,17 +1520,9 @@ static unsigned int bcmgenet_desc_rx(struct bcmgenet_priv *priv,
>
> /* Notify kernel */
> napi_gro_receive(&priv->napi, skb);
> - cb->skb = NULL;
> netif_dbg(priv, rx_status, dev, "pushed up to kernel\n");
>
> - /* refill RX path on the current control block */
> -refill:
> - err = bcmgenet_rx_refill(priv, cb);
> - if (err) {
> - priv->mib.alloc_rx_buff_failed++;
> - netif_err(priv, rx_err, dev, "Rx refill failed\n");
> - }
> -
> +next:
> rxpktprocessed++;
> if (likely(ring->read_ptr < ring->end_ptr))
> ring->read_ptr++;
> @@ -1553,7 +1541,7 @@ static int bcmgenet_alloc_rx_buffers(struct bcmgenet_priv *priv,
> struct bcmgenet_rx_ring *ring)
> {
> struct enet_cb *cb;
> - int ret = 0;
> + struct sk_buff *skb;
> int i;
>
> netif_dbg(priv, hw, priv->dev, "%s\n", __func__);
> @@ -1561,15 +1549,14 @@ static int bcmgenet_alloc_rx_buffers(struct bcmgenet_priv *priv,
> /* loop here for each buffer needing assign */
> for (i = 0; i < ring->size; i++) {
> cb = ring->cbs + i;
> - if (cb->skb)
> - continue;
> -
> - ret = bcmgenet_rx_refill(priv, cb);
> - if (ret)
> - break;
> + skb = bcmgenet_rx_refill(priv, cb);
> + if (skb)
> + dev_kfree_skb_any(skb);
> + if (!cb->skb)
> + return -ENOMEM;
> }
>
> - return ret;
> + return 0;
> }
>
> static void bcmgenet_free_rx_buffers(struct bcmgenet_priv *priv)
>
--
Florian
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists