From: Konstantin Khorenko Patch solves following problems: 1) Forgotten counter incrementation in sis900_rx() in case it doesn't get memory for skb, that leads to whole interface failure. Problem is accompanied with messages: eth0: Memory squeeze,deferring packet. eth0: NULL pointer encountered in Rx ring, skipping 2) If counter cur_rx overflows and there'll be temporary memory problems buffer can't be recreated later, when memory IS avaliable. 3) Limit the work in handler to prevent the endless packets processing if new packets are generated faster then handled. Signed-off-by: Konstantin Khorenko Signed-off-by: Vasily Averin Signed-off-by: Daniele Venzano Cc: Jeff Garzik Signed-off-by: Andrew Morton --- drivers/net/sis900.c | 16 ++++++++++++---- 1 files changed, 12 insertions(+), 4 deletions(-) diff -puN drivers/net/sis900.c~sis900-come-alive-after-temporary-memory-shortage drivers/net/sis900.c --- devel/drivers/net/sis900.c~sis900-come-alive-after-temporary-memory-shortage 2005-10-11 21:21:36.000000000 -0700 +++ devel-akpm/drivers/net/sis900.c 2005-10-11 21:21:36.000000000 -0700 @@ -1696,15 +1696,20 @@ static int sis900_rx(struct net_device * long ioaddr = net_dev->base_addr; unsigned int entry = sis_priv->cur_rx % NUM_RX_DESC; u32 rx_status = sis_priv->rx_ring[entry].cmdsts; + int rx_work_limit; if (netif_msg_rx_status(sis_priv)) printk(KERN_DEBUG "sis900_rx, cur_rx:%4.4d, dirty_rx:%4.4d " "status:0x%8.8x\n", sis_priv->cur_rx, sis_priv->dirty_rx, rx_status); + rx_work_limit = sis_priv->dirty_rx + NUM_RX_DESC - sis_priv->cur_rx; while (rx_status & OWN) { unsigned int rx_size; + if (--rx_work_limit < 0) + break; + rx_size = (rx_status & DSIZE) - CRC_SIZE; if (rx_status & (ABORT|OVERRUN|TOOLONG|RUNT|RXISERR|CRCERR|FAERR)) { @@ -1732,9 +1737,11 @@ static int sis900_rx(struct net_device * we are working on NULL sk_buff :-( */ if (sis_priv->rx_skbuff[entry] == NULL) { if (netif_msg_rx_err(sis_priv)) - printk(KERN_INFO "%s: NULL pointer " - "encountered in Rx ring, skipping\n", - net_dev->name); + printk(KERN_WARNING "%s: NULL pointer " + "encountered in Rx ring\n" + "cur_rx:%4.4d, dirty_rx:%4.4d\n", + net_dev->name, sis_priv->cur_rx, + sis_priv->dirty_rx); break; } @@ -1770,6 +1777,7 @@ static int sis900_rx(struct net_device * sis_priv->rx_ring[entry].cmdsts = 0; sis_priv->rx_ring[entry].bufptr = 0; sis_priv->stats.rx_dropped++; + sis_priv->cur_rx++; break; } skb->dev = net_dev; @@ -1787,7 +1795,7 @@ static int sis900_rx(struct net_device * /* refill the Rx buffer, what if the rate of refilling is slower * than consuming ?? */ - for (;sis_priv->cur_rx - sis_priv->dirty_rx > 0; sis_priv->dirty_rx++) { + for (; sis_priv->cur_rx != sis_priv->dirty_rx; sis_priv->dirty_rx++) { struct sk_buff *skb; entry = sis_priv->dirty_rx % NUM_RX_DESC; _