1 files changed, 18 insertions, 1 deletions

diff --git a/drivers/net/netxen/netxen_nic_main.c b/drivers/net/netxen/netxen_nic_main.c
index a8fb439a4d03..7144c255ce54 100644
--- a/drivers/net/netxen/netxen_nic_main.c
+++ b/drivers/net/netxen/netxen_nic_main.c
@@ -86,7 +86,24 @@ static struct pci_device_id netxen_pci_tbl[] __devinitdata = {
 
 MODULE_DEVICE_TABLE(pci, netxen_pci_tbl);
 
-struct workqueue_struct *netxen_workq;
+/*
+ * In netxen_nic_down(), we must wait for any pending callback requests into
+ * netxen_watchdog_task() to complete; eg otherwise the watchdog_timer could be
+ * reenabled right after it is deleted in netxen_nic_down().
+ * FLUSH_SCHEDULED_WORK()  does this synchronization.
+ *
+ * Normally, schedule_work()/flush_scheduled_work() could have worked, but
+ * netxen_nic_close() is invoked with kernel rtnl lock held. netif_carrier_off()
+ * call in netxen_nic_close() triggers a schedule_work(&linkwatch_work), and a
+ * subsequent call to flush_scheduled_work() in netxen_nic_down() would cause
+ * linkwatch_event() to be executed which also attempts to acquire the rtnl
+ * lock thus causing a deadlock.
+ */
+
+static struct workqueue_struct *netxen_workq;
+#define SCHEDULE_WORK(tp)       queue_work(netxen_workq, tp)
+#define FLUSH_SCHEDULED_WORK()  flush_workqueue(netxen_workq)
+
 static void netxen_watchdog(unsigned long);
 
 static void netxen_nic_update_cmd_producer(struct netxen_adapter *adapter,