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[PATCH] prism54: fix potential race in reset scheduling

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NET: prism54 - fix potential race in reset scheduling

There appears to be a race in reset scheduling logic - thread
responsible for reseting the interface should clear "reset
pending" flag before restarting the queue, otherwise timeout
handler might not schedule another reset even if it is needed.

This race is mostly theoretical as far as I can see but a race
nonetheless.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Dmitry Torokhov 2006-10-08 00:38:14 -04:00 committed by Jeff Garzik
parent 5c877fe58c
commit d18e0c4a54
1 changed files with 13 additions and 10 deletions
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23
drivers/net/wireless/prism54/islpci_eth.c
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@ -253,6 +253,7 @@ islpci_monitor_rx(islpci_private *priv, struct sk_buff **skb)
* header and without the FCS. But there a is a bit that
* indicates if the packet is corrupted :-) */
struct rfmon_header *hdr = (struct rfmon_header *) (*skb)->data;
if (hdr->flags & 0x01)
/* This one is bad. Drop it ! */
return -1;
@ -464,10 +465,8 @@ islpci_eth_receive(islpci_private *priv)
break;
}
/* update the fragment address */
control_block->rx_data_low[index].address = cpu_to_le32((u32)
priv->
pci_map_rx_address
[index]);
control_block->rx_data_low[index].address =
cpu_to_le32((u32)priv->pci_map_rx_address[index]);
wmb();
/* increment the driver read pointer */
@ -484,10 +483,12 @@ islpci_eth_receive(islpci_private *priv)
void
islpci_do_reset_and_wake(void *data)
{
islpci_private *priv = (islpci_private *) data;
islpci_private *priv = data;
islpci_reset(priv, 1);
netif_wake_queue(priv->ndev);
priv->reset_task_pending = 0;
smp_wmb();
netif_wake_queue(priv->ndev);
}
void
@ -499,12 +500,14 @@ islpci_eth_tx_timeout(struct net_device *ndev)
/* increment the transmit error counter */
statistics->tx_errors++;
printk(KERN_WARNING "%s: tx_timeout", ndev->name);
if (!priv->reset_task_pending) {
priv->reset_task_pending = 1;
printk(", scheduling a reset");
printk(KERN_WARNING
"%s: tx_timeout, scheduling reset", ndev->name);
netif_stop_queue(ndev);
priv->reset_task_pending = 1;
schedule_work(&priv->reset_task);
} else {
printk(KERN_WARNING
"%s: tx_timeout, waiting for reset", ndev->name);
}
printk("\n");
}