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staging: unisys: visornic: correctly clean up device on removal

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visornic_remove() is called to logically detach the visornic driver from a
visorbus-supplied device, which can happen either just prior to a
visorbus-supplied device disappearing, or as a result of an rmmod of
visornic.  Prior to this patch, logic was missing to properly clean up for
this removal, which was fixed via the following changes:

* A going_away flag is now used to interlock between device destruction and
  workqueue operations, protected by priv_lock.  I.e., setting
  going_away=true under lock guarantees that no new work items can get
  queued to the work queues.  going_away=true also short-circuits other
  operations to enable device destruction to proceed.

* Missing clean-up operations for the workqueues, netdev, debugfs entries,
  and the worker thread were added.

* Memory referenced from the visornic private devdata struct is now freed
  as part of devdata destruction.

Signed-off-by: Tim Sell <Timothy.Sell@unisys.com>
Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Tim Sell 2015-07-09 13:27:48 -04:00 committed by Greg Kroah-Hartman
parent fa15d6d346
commit 46df82267e
1 changed files with 63 additions and 2 deletions
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65
drivers/staging/unisys/visornic/visornic_main.c
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@ -162,6 +162,7 @@ struct visornic_devdata {
*/
bool server_down; /* IOPART is down */
bool server_change_state; /* Processing SERVER_CHANGESTATE msg */
bool going_away; /* device is being torn down */
struct dentry *eth_debugfs_dir;
struct visor_thread_info threadinfo;
u64 interrupts_rcvd;
@ -568,7 +569,17 @@ static int
visornic_serverdown(struct visornic_devdata *devdata,
visorbus_state_complete_func complete_func)
{
unsigned long flags;
spin_lock_irqsave(&devdata->priv_lock, flags);
if (!devdata->server_down && !devdata->server_change_state) {
if (devdata->going_away) {
spin_unlock_irqrestore(&devdata->priv_lock, flags);
dev_dbg(&devdata->dev->device,
"%s aborting because device removal pending\n",
__func__);
return -ENODEV;
}
devdata->server_change_state = true;
devdata->server_down_complete_func = complete_func;
queue_work(visornic_serverdown_workqueue,
@ -576,8 +587,10 @@ visornic_serverdown(struct visornic_devdata *devdata,
} else if (devdata->server_change_state) {
dev_dbg(&devdata->dev->device, "%s changing state\n",
__func__);
spin_unlock_irqrestore(&devdata->priv_lock, flags);
return -EINVAL;
}
spin_unlock_irqrestore(&devdata->priv_lock, flags);
return 0;
}
@ -1236,6 +1249,14 @@ visornic_xmit_timeout(struct net_device *netdev)
unsigned long flags;
spin_lock_irqsave(&devdata->priv_lock, flags);
if (devdata->going_away) {
spin_unlock_irqrestore(&devdata->priv_lock, flags);
dev_dbg(&devdata->dev->device,
"%s aborting because device removal pending\n",
__func__);
return;
}
/* Ensure that a ServerDown message hasn't been received */
if (!devdata->enabled ||
(devdata->server_down && !devdata->server_change_state)) {
@ -1244,9 +1265,8 @@ visornic_xmit_timeout(struct net_device *netdev)
spin_unlock_irqrestore(&devdata->priv_lock, flags);
return;
}
spin_unlock_irqrestore(&devdata->priv_lock, flags);
queue_work(visornic_timeout_reset_workqueue, &devdata->timeout_reset);
spin_unlock_irqrestore(&devdata->priv_lock, flags);
}
/**
@ -1614,6 +1634,9 @@ static void devdata_release(struct kref *mykref)
spin_lock(&lock_all_devices);
list_del(&devdata->list_all);
spin_unlock(&lock_all_devices);
kfree(devdata->rcvbuf);
kfree(devdata->cmdrsp_rcv);
kfree(devdata->xmit_cmdrsp);
kfree(devdata);
}
@ -2025,13 +2048,51 @@ static void host_side_disappeared(struct visornic_devdata *devdata)
static void visornic_remove(struct visor_device *dev)
{
struct visornic_devdata *devdata = dev_get_drvdata(&dev->device);
struct net_device *netdev;
unsigned long flags;
if (!devdata) {
dev_err(&dev->device, "%s no devdata\n", __func__);
return;
}
spin_lock_irqsave(&devdata->priv_lock, flags);
if (devdata->going_away) {
spin_unlock_irqrestore(&devdata->priv_lock, flags);
dev_err(&dev->device, "%s already being removed\n", __func__);
return;
}
devdata->going_away = true;
spin_unlock_irqrestore(&devdata->priv_lock, flags);
netdev = devdata->netdev;
if (!netdev) {
dev_err(&dev->device, "%s not net device\n", __func__);
return;
}
/* going_away prevents new items being added to the workqueues */
flush_workqueue(visornic_serverdown_workqueue);
flush_workqueue(visornic_timeout_reset_workqueue);
debugfs_remove_recursive(devdata->eth_debugfs_dir);
unregister_netdev(netdev); /* this will call visornic_close() */
/* this had to wait until last because visornic_close() /
* visornic_disable_with_timeout() polls waiting for state that is
* only updated by the thread
*/
if (devdata->threadinfo.id) {
visor_thread_stop(&devdata->threadinfo);
if (devdata->threadinfo.id) {
dev_err(&dev->device, "%s cannot stop worker thread\n",
__func__);
return;
}
}
dev_set_drvdata(&dev->device, NULL);
host_side_disappeared(devdata);
free_netdev(netdev);
kref_put(&devdata->kref, devdata_release);
}