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sunvnet: Schedule maybe_tx_wakeup() as a tasklet from ldc_rx path

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At the tail of vnet_event(), if we hit the maybe_tx_wakeup()
condition, we try to take the netif_tx_lock() in the
recv-interrupt-context and can deadlock with dev_watchdog().
vnet_event() should schedule maybe_tx_wakeup() as a tasklet
to avoid this deadlock

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sowmini Varadhan 2014-08-13 10:29:41 -04:00 committed by David S. Miller
parent adddc32d6f
commit 1d311ad2f9
2 changed files with 14 additions and 2 deletions
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12
drivers/net/ethernet/sun/sunvnet.c
View File

@ -488,8 +488,9 @@ static int handle_mcast(struct vnet_port *port, void *msgbuf)
return 0;
}
static void maybe_tx_wakeup(struct vnet *vp)
static void maybe_tx_wakeup(unsigned long param)
{
struct vnet *vp = (struct vnet *)param;
struct net_device *dev = vp->dev;
netif_tx_lock(dev);
@ -586,8 +587,13 @@ static void vnet_event(void *arg, int event)
break;
}
spin_unlock(&vio->lock);
/* Kick off a tasklet to wake the queue. We cannot call
* maybe_tx_wakeup directly here because we could deadlock on
* netif_tx_lock() with dev_watchdog()
*/
if (unlikely(tx_wakeup && err != -ECONNRESET))
maybe_tx_wakeup(port->vp);
tasklet_schedule(&port->vp->vnet_tx_wakeup);
local_irq_restore(flags);
}
@ -1070,6 +1076,7 @@ static struct vnet *vnet_new(const u64 *local_mac)
vp = netdev_priv(dev);
spin_lock_init(&vp->lock);
tasklet_init(&vp->vnet_tx_wakeup, maybe_tx_wakeup, (unsigned long)vp);
vp->dev = dev;
INIT_LIST_HEAD(&vp->port_list);
@ -1129,6 +1136,7 @@ static void vnet_cleanup(void)
vp = list_first_entry(&vnet_list, struct vnet, list);
list_del(&vp->list);
dev = vp->dev;
tasklet_kill(&vp->vnet_tx_wakeup);
/* vio_unregister_driver() should have cleaned up port_list */
BUG_ON(!list_empty(&vp->port_list));
unregister_netdev(dev);

4
drivers/net/ethernet/sun/sunvnet.h
View File

@ -1,6 +1,8 @@
#ifndef _SUNVNET_H
#define _SUNVNET_H
#include <linux/interrupt.h>
#define DESC_NCOOKIES(entry_size) \
((entry_size) - sizeof(struct vio_net_desc))
@ -78,6 +80,8 @@ struct vnet {
struct list_head list;
u64 local_mac;
struct tasklet_struct vnet_tx_wakeup;
};
#endif /* _SUNVNET_H */