Attachment 189261 Details for Bug 251978 – patch prohibits cross-cpu dev processing

[patch] patch prohibits cross-cpu dev processing

linux-2.6.9-netrx-netpoll-race.patch (text/plain), 2.49 KB, created by Tina Yang on 2007-09-06 21:38:11 UTC

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Creator: Tina Yang

Created: 2007-09-06 21:38:11 UTC

Size: 2.49 KB

patch

obsolete

>--- linux-2.6.9/net/core/netpoll.c.orig	2007-09-06 14:03:57.000000000 -0700
>+++ linux-2.6.9/net/core/netpoll.c	2007-09-06 14:03:50.000000000 -0700
>@@ -97,13 +97,20 @@
> 	if (test_bit(__LINK_STATE_RX_SCHED, &dev->state) &&
> 	    npinfo->poll_owner != smp_processor_id() &&
> 	    spin_trylock(&npinfo->poll_lock)) {
>-		npinfo->rx_flags |= NETPOLL_RX_DROP;
>-		atomic_inc(&trapped);
> 
>-		dev->poll(dev, &budget);
>+		/* Don't trespass unless in netdump mode when 
>+		 * only one cpu is active.
>+		 */
>+		if (netdump_mode || 
>+		    dev->poll_list_owner == smp_processor_id()) { 
>+			npinfo->rx_flags |= NETPOLL_RX_DROP;
>+			atomic_inc(&trapped);
> 
>-		atomic_dec(&trapped);
>-		npinfo->rx_flags &= ~NETPOLL_RX_DROP;
>+			dev->poll(dev, &budget);
>+
>+			atomic_dec(&trapped);
>+			npinfo->rx_flags &= ~NETPOLL_RX_DROP;
>+		}
> 		spin_unlock(&npinfo->poll_lock);
> 	}
> }
>@@ -132,9 +139,17 @@
> 		return;
> 
> 	/* Process pending work on NIC */
>+#ifdef CONFIG_SMP
>+	/* Ensure the same poll_list
>+	 */
>+	preempt_disable();
>+#endif
> 	dev->poll_controller(dev);
> 	if (dev->poll)
> 		poll_napi(dev);
>+#ifdef CONFIG_SMP
>+	preempt_enable();
>+#endif
> 
> 	service_arp_queue(npi);
> 
>--- linux-2.6.9/drivers/net/net_init.c.orig	2007-09-06 14:04:25.000000000 -0700
>+++ linux-2.6.9/drivers/net/net_init.c	2007-09-06 13:19:29.000000000 -0700
>@@ -109,6 +109,7 @@
> 	 * implemented to preserve kABI.
> 	 */
> 	dev->priv_flags |= IFF_EXTENDED;
>+	dev->poll_list_owner = -1;
> 
> 	return dev;
> }
>--- linux-2.6.9/include/linux/netdevice.h.orig	2007-09-06 14:04:14.000000000 -0700
>+++ linux-2.6.9/include/linux/netdevice.h	2007-09-06 14:08:30.000000000 -0700
>@@ -368,6 +368,7 @@
> 	void			*ax25_ptr;	/* AX.25 specific data */
> 
> 	struct list_head	poll_list;	/* Link to poll list	*/
>+	int			poll_list_owner;/* which cpu's poll list it's on */
> 	int			quota;
> 	int			weight;
> 
>@@ -840,6 +841,7 @@
> 	local_irq_save(flags);
> 	dev_hold(dev);
> 	list_add_tail(&dev->poll_list, &__get_cpu_var(softnet_data).poll_list);
>+	dev->poll_list_owner = smp_processor_id();
> 	if (dev->quota < 0)
> 		dev->quota += dev->weight;
> 	else
>@@ -861,6 +863,7 @@
> {
> 	dev->quota += undo;
> 	list_add_tail(&dev->poll_list, &__get_cpu_var(softnet_data).poll_list);
>+	dev->poll_list_owner = smp_processor_id();
> 	__raise_softirq_irqoff(NET_RX_SOFTIRQ);
> }
> 
>@@ -889,6 +892,7 @@
> 	local_irq_save(flags);
> 	BUG_ON(!test_bit(__LINK_STATE_RX_SCHED, &dev->state));
> 	list_del(&dev->poll_list);
>+	dev->poll_list_owner = -1;
> 	smp_mb__before_clear_bit();
> 	clear_bit(__LINK_STATE_RX_SCHED, &dev->state);
> 	local_irq_restore(flags);

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Attachments on bug 251978: 161198 | 181601 | 183141 | 183961 | 185531 | 185541 | 186681 | 187461 | 187831 | 189261 | 190311 | 190351 | 194551