WAN: Fix a TX IRQ causing BUG() in PC300 and PCI200SYN drivers.

We must not wake the TX queue without free TX descriptors.
sca_xmit() expects at least one free descriptor and BUGs otherwise.

Problem reported and fix tested by Bernie Innocenti and Ward Vandewege.

Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Krzysztof Halasa 2010-12-12 12:06:47 +00:00 committed by David S. Miller
parent 9f5449611c
commit eaff9453d3

View file

@ -293,6 +293,7 @@ static inline void sca_tx_done(port_t *port)
struct net_device *dev = port->netdev;
card_t* card = port->card;
u8 stat;
unsigned count = 0;
spin_lock(&port->lock);
@ -316,10 +317,12 @@ static inline void sca_tx_done(port_t *port)
dev->stats.tx_bytes += readw(&desc->len);
}
writeb(0, &desc->stat); /* Free descriptor */
count++;
port->txlast = (port->txlast + 1) % card->tx_ring_buffers;
}
netif_wake_queue(dev);
if (count)
netif_wake_queue(dev);
spin_unlock(&port->lock);
}