From 815b97c6b8861f2e539c9ecb44c02b7b8ac11ca4 Mon Sep 17 00:00:00 2001 From: Andy Fleming Date: Tue, 22 Apr 2008 17:18:29 -0500 Subject: [PATCH] gianfar: Fix skb allocation strategy gianfar was unable to handle failed skb allocation for rx buffers, so we were spinning until it succeeded. Actually, it was worse--we were spinning for a long time, and then silently failing. Instead, we take Stephen Hemminger's suggestion to try the allocation earlier, and drop the packet if it failed. We also make a couple of tweaks to how buffer descriptors are set up. Signed-off-by: Andy Fleming Signed-off-by: Jeff Garzik --- drivers/net/gianfar.c | 100 +++++++++++++++++++++++++++--------------- 1 file changed, 65 insertions(+), 35 deletions(-) diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c index b917616bf6..99a4b99093 100644 --- a/drivers/net/gianfar.c +++ b/drivers/net/gianfar.c @@ -98,7 +98,6 @@ #include "gianfar_mii.h" #define TX_TIMEOUT (1*HZ) -#define SKB_ALLOC_TIMEOUT 1000000 #undef BRIEF_GFAR_ERRORS #undef VERBOSE_GFAR_ERRORS @@ -115,7 +114,9 @@ static int gfar_enet_open(struct net_device *dev); static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev); static void gfar_timeout(struct net_device *dev); static int gfar_close(struct net_device *dev); -struct sk_buff *gfar_new_skb(struct net_device *dev, struct rxbd8 *bdp); +struct sk_buff *gfar_new_skb(struct net_device *dev); +static void gfar_new_rxbdp(struct net_device *dev, struct rxbd8 *bdp, + struct sk_buff *skb); static int gfar_set_mac_address(struct net_device *dev); static int gfar_change_mtu(struct net_device *dev, int new_mtu); static irqreturn_t gfar_error(int irq, void *dev_id); @@ -783,14 +784,21 @@ int startup_gfar(struct net_device *dev) rxbdp = priv->rx_bd_base; for (i = 0; i < priv->rx_ring_size; i++) { - struct sk_buff *skb = NULL; + struct sk_buff *skb; - rxbdp->status = 0; + skb = gfar_new_skb(dev); - skb = gfar_new_skb(dev, rxbdp); + if (!skb) { + printk(KERN_ERR "%s: Can't allocate RX buffers\n", + dev->name); + + goto err_rxalloc_fail; + } priv->rx_skbuff[i] = skb; + gfar_new_rxbdp(dev, rxbdp, skb); + rxbdp++; } @@ -916,6 +924,7 @@ rx_irq_fail: tx_irq_fail: free_irq(priv->interruptError, dev); err_irq_fail: +err_rxalloc_fail: rx_skb_fail: free_skb_resources(priv); tx_skb_fail: @@ -1328,18 +1337,37 @@ static irqreturn_t gfar_transmit(int irq, void *dev_id) return IRQ_HANDLED; } -struct sk_buff * gfar_new_skb(struct net_device *dev, struct rxbd8 *bdp) +static void gfar_new_rxbdp(struct net_device *dev, struct rxbd8 *bdp, + struct sk_buff *skb) +{ + struct gfar_private *priv = netdev_priv(dev); + u32 * status_len = (u32 *)bdp; + u16 flags; + + bdp->bufPtr = dma_map_single(&dev->dev, skb->data, + priv->rx_buffer_size, DMA_FROM_DEVICE); + + flags = RXBD_EMPTY | RXBD_INTERRUPT; + + if (bdp == priv->rx_bd_base + priv->rx_ring_size - 1) + flags |= RXBD_WRAP; + + eieio(); + + *status_len = (u32)flags << 16; +} + + +struct sk_buff * gfar_new_skb(struct net_device *dev) { unsigned int alignamount; struct gfar_private *priv = netdev_priv(dev); struct sk_buff *skb = NULL; - unsigned int timeout = SKB_ALLOC_TIMEOUT; /* We have to allocate the skb, so keep trying till we succeed */ - while ((!skb) && timeout--) - skb = dev_alloc_skb(priv->rx_buffer_size + RXBUF_ALIGNMENT); + skb = netdev_alloc_skb(dev, priv->rx_buffer_size + RXBUF_ALIGNMENT); - if (NULL == skb) + if (!skb) return NULL; alignamount = RXBUF_ALIGNMENT - @@ -1350,15 +1378,6 @@ struct sk_buff * gfar_new_skb(struct net_device *dev, struct rxbd8 *bdp) */ skb_reserve(skb, alignamount); - bdp->bufPtr = dma_map_single(&dev->dev, skb->data, - priv->rx_buffer_size, DMA_FROM_DEVICE); - - bdp->length = 0; - - /* Mark the buffer empty */ - eieio(); - bdp->status |= (RXBD_EMPTY | RXBD_INTERRUPT); - return skb; } @@ -1544,10 +1563,31 @@ int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit) bdp = priv->cur_rx; while (!((bdp->status & RXBD_EMPTY) || (--rx_work_limit < 0))) { + struct sk_buff *newskb; rmb(); + + /* Add another skb for the future */ + newskb = gfar_new_skb(dev); + skb = priv->rx_skbuff[priv->skb_currx]; - if ((bdp->status & RXBD_LAST) && !(bdp->status & RXBD_ERR)) { + /* We drop the frame if we failed to allocate a new buffer */ + if (unlikely(!newskb || !(bdp->status & RXBD_LAST) || + bdp->status & RXBD_ERR)) { + count_errors(bdp->status, dev); + + if (unlikely(!newskb)) + newskb = skb; + + if (skb) { + dma_unmap_single(&priv->dev->dev, + bdp->bufPtr, + priv->rx_buffer_size, + DMA_FROM_DEVICE); + + dev_kfree_skb_any(skb); + } + } else { /* Increment the number of packets */ dev->stats.rx_packets++; howmany++; @@ -1558,23 +1598,14 @@ int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit) gfar_process_frame(dev, skb, pkt_len); dev->stats.rx_bytes += pkt_len; - } else { - count_errors(bdp->status, dev); - - if (skb) - dev_kfree_skb_any(skb); - - priv->rx_skbuff[priv->skb_currx] = NULL; } dev->last_rx = jiffies; - /* Clear the status flags for this buffer */ - bdp->status &= ~RXBD_STATS; + priv->rx_skbuff[priv->skb_currx] = newskb; - /* Add another skb for the future */ - skb = gfar_new_skb(dev, bdp); - priv->rx_skbuff[priv->skb_currx] = skb; + /* Setup the new bdp */ + gfar_new_rxbdp(dev, bdp, newskb); /* Update to the next pointer */ if (bdp->status & RXBD_WRAP) @@ -1584,9 +1615,8 @@ int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit) /* update to point at the next skb */ priv->skb_currx = - (priv->skb_currx + - 1) & RX_RING_MOD_MASK(priv->rx_ring_size); - + (priv->skb_currx + 1) & + RX_RING_MOD_MASK(priv->rx_ring_size); } /* Update the current rxbd pointer to be the next one */ -- 2.39.5