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Commit 1d311ad2 authored by Sowmini Varadhan's avatar Sowmini Varadhan Committed by David S. Miller
Browse files

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



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: default avatarSowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent adddc32d

drivers/net/ethernet/sun/sunvnet.c

+10 −2
Original line number Diff line number Diff line
@@ -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);

drivers/net/ethernet/sun/sunvnet.h

+4 −0
Original line number Diff line number Diff line 
#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 */