summaryrefslogtreecommitdiff
path: root/drivers
diff options
context:
space:
mode:
authorPetri Gynther <pgynther@google.com>2015-03-12 15:48:00 -0700
committerDavid S. Miller <davem@davemloft.net>2015-03-13 15:48:15 -0400
commitd6707bec598649450ee0887bf11896e525777874 (patch)
tree8e33b10d376a8365d6d369ffd52ae8a461737719 /drivers
parent5e1459ca13eddea516f8c56122cb3253e7b0e03e (diff)
net: bcmgenet: rewrite bcmgenet_rx_refill()
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. Signed-off-by: Petri Gynther <pgynther@google.com> Tested-by: Jaedon Shin <jaedon.shin@gmail.com>-- Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Tested-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/ethernet/broadcom/genet/bcmgenet.c99
1 files changed, 43 insertions, 56 deletions
diff --git a/drivers/net/ethernet/broadcom/genet/bcmgenet.c b/drivers/net/ethernet/broadcom/genet/bcmgenet.c
index d3be1aeb7f47..875967e8d719 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)