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Commit c46ac946 authored by Florian Westphal's avatar Florian Westphal Committed by Jeff Garzik
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DM9000: fix interface hang under load 



When transferring data at full speed, the DM9000 network interface
sometimes stops sending/receiving data. Worse, ksoftirqd consumes
100% cpu and the net tx watchdog never triggers.
Fix by spin_lock_irqsave() in dm9000_start_xmit() to prevent the
interrupt handler from interfering.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarJeff Garzik <jeff@garzik.org>
parent bc1e0a09

drivers/net/dm9000.c

+7 −18
Original line number Diff line number Diff line
@@ -700,6 +700,7 @@ dm9000_init_dm9000(struct net_device *dev) 
static int

dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev)

{

	unsigned long flags;

	board_info_t *db = (board_info_t *) dev->priv;



	PRINTK3("dm9000_start_xmit\n");
@@ -707,10 +708,7 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	if (db->tx_pkt_cnt > 1)

		return 1;



	netif_stop_queue(dev);



	/* Disable all interrupts */

	iow(db, DM9000_IMR, IMR_PAR);

	spin_lock_irqsave(&db->lock, flags);



	/* Move data to DM9000 TX RAM */

	writeb(DM9000_MWCMD, db->io_addr);
@@ -718,12 +716,9 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev) 
	(db->outblk)(db->io_data, skb->data, skb->len);

	db->stats.tx_bytes += skb->len;



	/* TX control: First packet immediately send, second packet queue */

	if (db->tx_pkt_cnt == 0) {



		/* First Packet */

	db->tx_pkt_cnt++;



	/* TX control: First packet immediately send, second packet queue */

	if (db->tx_pkt_cnt == 1) {

		/* Set TX length to DM9000 */

		iow(db, DM9000_TXPLL, skb->len & 0xff);

		iow(db, DM9000_TXPLH, (skb->len >> 8) & 0xff);
@@ -732,23 +727,17 @@ dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev) 
		iow(db, DM9000_TCR, TCR_TXREQ);	/* Cleared after TX complete */



		dev->trans_start = jiffies;	/* save the time stamp */



	} else {

		/* Second packet */

		db->tx_pkt_cnt++;

		db->queue_pkt_len = skb->len;

		netif_stop_queue(dev);

	}



	spin_unlock_irqrestore(&db->lock, flags);



	/* free this SKB */

	dev_kfree_skb(skb);



	/* Re-enable resource check */

	if (db->tx_pkt_cnt == 1)

		netif_wake_queue(dev);



	/* Re-enable interrupt */

	iow(db, DM9000_IMR, IMR_PAR | IMR_PTM | IMR_PRM);



	return 0;

}