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IB/mad: Fix oopsable race on device removal

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Fix an oopsable race debugged by Eli Cohen <eli@mellanox.co.il>:
After removing the port from port_list, ib_mad_port_close flushes
port_priv->wq before destroying the special QPs. This means that a
completion event could arrive, and queue a new work in this work queue
after flush.

This patch also removes an unnecessary flush_workqueue():
destroy_workqueue() already includes a flush.

Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Signed-off-by: Roland Dreier <rolandd@cisco.com>
This commit is contained in:
Michael S. Tsirkin 2006-03-20 10:08:25 -08:00 committed by Roland Dreier
parent bf17c1c7cc
commit dc05980dd7
1 changed files with 14 additions and 7 deletions
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21
drivers/infiniband/core/mad.c
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@ -2364,8 +2364,12 @@ static void timeout_sends(void *data)
static void ib_mad_thread_completion_handler(struct ib_cq *cq, void *arg)
{
struct ib_mad_port_private *port_priv = cq->cq_context;
unsigned long flags;
queue_work(port_priv->wq, &port_priv->work);
spin_lock_irqsave(&ib_mad_port_list_lock, flags);
if (!list_empty(&port_priv->port_list))
queue_work(port_priv->wq, &port_priv->work);
spin_unlock_irqrestore(&ib_mad_port_list_lock, flags);
}
/*
@ -2677,18 +2681,23 @@ static int ib_mad_port_open(struct ib_device *device,
}
INIT_WORK(&port_priv->work, ib_mad_completion_handler, port_priv);
spin_lock_irqsave(&ib_mad_port_list_lock, flags);
list_add_tail(&port_priv->port_list, &ib_mad_port_list);
spin_unlock_irqrestore(&ib_mad_port_list_lock, flags);
ret = ib_mad_port_start(port_priv);
if (ret) {
printk(KERN_ERR PFX "Couldn't start port\n");
goto error9;
}
spin_lock_irqsave(&ib_mad_port_list_lock, flags);
list_add_tail(&port_priv->port_list, &ib_mad_port_list);
spin_unlock_irqrestore(&ib_mad_port_list_lock, flags);
return 0;
error9:
spin_lock_irqsave(&ib_mad_port_list_lock, flags);
list_del_init(&port_priv->port_list);
spin_unlock_irqrestore(&ib_mad_port_list_lock, flags);
destroy_workqueue(port_priv->wq);
error8:
destroy_mad_qp(&port_priv->qp_info[1]);
@ -2725,11 +2734,9 @@ static int ib_mad_port_close(struct ib_device *device, int port_num)
printk(KERN_ERR PFX "Port %d not found\n", port_num);
return -ENODEV;
}
list_del(&port_priv->port_list);
list_del_init(&port_priv->port_list);
spin_unlock_irqrestore(&ib_mad_port_list_lock, flags);
/* Stop processing completions. */
flush_workqueue(port_priv->wq);
destroy_workqueue(port_priv->wq);
destroy_mad_qp(&port_priv->qp_info[1]);
destroy_mad_qp(&port_priv->qp_info[0]);