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IB/cm: Do not queue work to a device that's going away

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Whenever ib_cm gets remove_one call, like when there is a hot-unplug
event, the driver should mark itself as going_down and confirm that no
new works are going to be queued for that device.
so, the order of the actions are:
1. mark the going_down bit.
2. flush the wq.
3. [make sure no new works for that device.]
4. unregister mad agent.

otherwise, works that are already queued can be scheduled after the mad
agent was freed.

Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Erez Shitrit 2015-06-25 17:13:22 +03:00 committed by Doug Ledford
parent 3fdf70acec
commit be4b499323
1 changed files with 55 additions and 6 deletions
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61
drivers/infiniband/core/cm.c
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@ -169,6 +169,7 @@ struct cm_device {
struct ib_device *ib_device;
struct device *device;
u8 ack_delay;
int going_down;
struct cm_port *port[0];
};
@ -805,6 +806,11 @@ static void cm_enter_timewait(struct cm_id_private *cm_id_priv)
{
int wait_time;
unsigned long flags;
struct cm_device *cm_dev;
cm_dev = ib_get_client_data(cm_id_priv->id.device, &cm_client);
if (!cm_dev)
return;
spin_lock_irqsave(&cm.lock, flags);
cm_cleanup_timewait(cm_id_priv->timewait_info);
@ -818,8 +824,14 @@ static void cm_enter_timewait(struct cm_id_private *cm_id_priv)
*/
cm_id_priv->id.state = IB_CM_TIMEWAIT;
wait_time = cm_convert_to_ms(cm_id_priv->av.timeout);
queue_delayed_work(cm.wq, &cm_id_priv->timewait_info->work.work,
msecs_to_jiffies(wait_time));
/* Check if the device started its remove_one */
spin_lock_irq(&cm.lock);
if (!cm_dev->going_down)
queue_delayed_work(cm.wq, &cm_id_priv->timewait_info->work.work,
msecs_to_jiffies(wait_time));
spin_unlock_irq(&cm.lock);
cm_id_priv->timewait_info = NULL;
}
@ -3305,6 +3317,11 @@ static int cm_establish(struct ib_cm_id *cm_id)
struct cm_work *work;
unsigned long flags;
int ret = 0;
struct cm_device *cm_dev;
cm_dev = ib_get_client_data(cm_id->device, &cm_client);
if (!cm_dev)
return -ENODEV;
work = kmalloc(sizeof *work, GFP_ATOMIC);
if (!work)
@ -3343,7 +3360,17 @@ static int cm_establish(struct ib_cm_id *cm_id)
work->remote_id = cm_id->remote_id;
work->mad_recv_wc = NULL;
work->cm_event.event = IB_CM_USER_ESTABLISHED;
queue_delayed_work(cm.wq, &work->work, 0);
/* Check if the device started its remove_one */
spin_lock_irq(&cm.lock);
if (!cm_dev->going_down) {
queue_delayed_work(cm.wq, &work->work, 0);
} else {
kfree(work);
ret = -ENODEV;
}
spin_unlock_irq(&cm.lock);
out:
return ret;
}
@ -3394,6 +3421,7 @@ static void cm_recv_handler(struct ib_mad_agent *mad_agent,
enum ib_cm_event_type event;
u16 attr_id;
int paths = 0;
int going_down = 0;
switch (mad_recv_wc->recv_buf.mad->mad_hdr.attr_id) {
case CM_REQ_ATTR_ID:
@ -3452,7 +3480,19 @@ static void cm_recv_handler(struct ib_mad_agent *mad_agent,
work->cm_event.event = event;
work->mad_recv_wc = mad_recv_wc;
work->port = port;
queue_delayed_work(cm.wq, &work->work, 0);
/* Check if the device started its remove_one */
spin_lock_irq(&cm.lock);
if (!port->cm_dev->going_down)
queue_delayed_work(cm.wq, &work->work, 0);
else
going_down = 1;
spin_unlock_irq(&cm.lock);
if (going_down) {
kfree(work);
ib_free_recv_mad(mad_recv_wc);
}
}
static int cm_init_qp_init_attr(struct cm_id_private *cm_id_priv,
@ -3771,7 +3811,7 @@ static void cm_add_one(struct ib_device *ib_device)
cm_dev->ib_device = ib_device;
cm_get_ack_delay(cm_dev);
cm_dev->going_down = 0;
cm_dev->device = device_create(&cm_class, &ib_device->dev,
MKDEV(0, 0), NULL,
"%s", ib_device->name);
@ -3864,14 +3904,23 @@ static void cm_remove_one(struct ib_device *ib_device)
list_del(&cm_dev->list);
write_unlock_irqrestore(&cm.device_lock, flags);
spin_lock_irq(&cm.lock);
cm_dev->going_down = 1;
spin_unlock_irq(&cm.lock);
for (i = 1; i <= ib_device->phys_port_cnt; i++) {
if (!rdma_cap_ib_cm(ib_device, i))
continue;
port = cm_dev->port[i-1];
ib_modify_port(ib_device, port->port_num, 0, &port_modify);
ib_unregister_mad_agent(port->mad_agent);
/*
* We flush the queue here after the going_down set, this
* verify that no new works will be queued in the recv handler,
* after that we can call the unregister_mad_agent
*/
flush_workqueue(cm.wq);
ib_unregister_mad_agent(port->mad_agent);
cm_remove_port_fs(port);
}
device_unregister(cm_dev->device);