[SCSI] fcoe: Fix module ref count bug by adding NETDEV UNREGISTER handling
Fixes reference counting on fcoe_instance and net_device, and adds NETDEV_UNREGISTER notifier handling so that you can unload network drivers. FCoE no longer increments the module use count for the network driver. On an NETDEV_UNREGISTER event, destroying the FCoE instance is deferred to a workqueue context to avoid RTNL deadlocks. Based in part by an earlier patch from John Fastabend John's patch description: Currently, the netdev module ref count is not decremented with module_put() when the module is unloaded while fcoe instances are present. To fix this removed reference count on netdev module completely and added functionality to netdev event handling for NETDEV_UNREGISTER events. This allows fcoe to remove devices cleanly when the netdev module is unloaded so we no longer need to hold a reference count for the netdev module. Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: Robert Love <robert.w.love@intel.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
This commit is contained in:
parent
c863df33bb
commit
2e70e24151
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@ -74,12 +74,13 @@ static int fcoe_link_ok(struct fc_lport *lp);
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static struct fc_lport *fcoe_hostlist_lookup(const struct net_device *);
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static int fcoe_hostlist_add(const struct fc_lport *);
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static int fcoe_hostlist_remove(const struct fc_lport *);
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static void fcoe_check_wait_queue(struct fc_lport *, struct sk_buff *);
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static int fcoe_device_notification(struct notifier_block *, ulong, void *);
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static void fcoe_dev_setup(void);
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static void fcoe_dev_cleanup(void);
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static struct fcoe_interface *
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fcoe_hostlist_lookup_port(const struct net_device *dev);
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/* notification function from net device */
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static struct notifier_block fcoe_notifier = {
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@ -149,6 +150,7 @@ static int fcoe_fip_recv(struct sk_buff *skb, struct net_device *dev,
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* @netdev : ptr to the associated netdevice struct
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*
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* Returns : 0 for success
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* Locking: must be called with the RTNL mutex held
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*/
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static int fcoe_interface_setup(struct fcoe_interface *fcoe,
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struct net_device *netdev)
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@ -188,13 +190,11 @@ static int fcoe_interface_setup(struct fcoe_interface *fcoe,
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* or enter promiscuous mode if not capable of listening
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* for multiple unicast MACs.
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*/
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rtnl_lock();
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memcpy(flogi_maddr, (u8[6]) FC_FCOE_FLOGI_MAC, ETH_ALEN);
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dev_unicast_add(netdev, flogi_maddr);
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if (fip->spma)
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dev_unicast_add(netdev, fip->ctl_src_addr);
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dev_mc_add(netdev, FIP_ALL_ENODE_MACS, ETH_ALEN, 0);
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rtnl_unlock();
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/*
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* setup the receive function from ethernet driver
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@ -215,6 +215,7 @@ static int fcoe_interface_setup(struct fcoe_interface *fcoe,
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static void fcoe_fip_send(struct fcoe_ctlr *fip, struct sk_buff *skb);
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static void fcoe_update_src_mac(struct fcoe_ctlr *fip, u8 *old, u8 *new);
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static void fcoe_destroy_work(struct work_struct *work);
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/**
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* fcoe_interface_create()
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@ -232,6 +233,7 @@ static struct fcoe_interface *fcoe_interface_create(struct net_device *netdev)
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return NULL;
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}
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dev_hold(netdev);
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kref_init(&fcoe->kref);
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/*
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@ -249,6 +251,8 @@ static struct fcoe_interface *fcoe_interface_create(struct net_device *netdev)
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/**
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* fcoe_interface_cleanup() - clean up netdev configurations
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* @fcoe:
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*
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* Caller must be holding the RTNL mutex
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*/
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void fcoe_interface_cleanup(struct fcoe_interface *fcoe)
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{
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@ -266,11 +270,7 @@ void fcoe_interface_cleanup(struct fcoe_interface *fcoe)
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__dev_remove_pack(&fcoe->fip_packet_type);
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synchronize_net();
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/* tear-down the FCoE controller */
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fcoe_ctlr_destroy(&fcoe->ctlr);
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/* Delete secondary MAC addresses */
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rtnl_lock();
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memcpy(flogi_maddr, (u8[6]) FC_FCOE_FLOGI_MAC, ETH_ALEN);
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dev_unicast_delete(netdev, flogi_maddr);
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if (!is_zero_ether_addr(fip->data_src_addr))
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@ -278,7 +278,6 @@ void fcoe_interface_cleanup(struct fcoe_interface *fcoe)
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if (fip->spma)
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dev_unicast_delete(netdev, fip->ctl_src_addr);
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dev_mc_delete(netdev, FIP_ALL_ENODE_MACS, ETH_ALEN, 0);
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rtnl_unlock();
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}
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/**
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@ -288,10 +287,14 @@ void fcoe_interface_cleanup(struct fcoe_interface *fcoe)
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static void fcoe_interface_release(struct kref *kref)
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{
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struct fcoe_interface *fcoe;
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struct net_device *netdev;
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fcoe = container_of(kref, struct fcoe_interface, kref);
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fcoe_interface_cleanup(fcoe);
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netdev = fcoe->netdev;
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/* tear-down the FCoE controller */
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fcoe_ctlr_destroy(&fcoe->ctlr);
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kfree(fcoe);
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dev_put(netdev);
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}
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/**
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@ -642,8 +645,7 @@ static void fcoe_if_destroy(struct fc_lport *lport)
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/* Free memory used by statistical counters */
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fc_lport_free_stats(lport);
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/* Release the net_device and Scsi_Host */
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dev_put(netdev);
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/* Release the Scsi_Host */
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scsi_host_put(lport->host);
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}
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@ -718,7 +720,9 @@ static struct fc_lport *fcoe_if_create(struct fcoe_interface *fcoe,
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}
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lport = shost_priv(shost);
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port = lport_priv(lport);
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port->lport = lport;
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port->fcoe = fcoe;
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INIT_WORK(&port->destroy_work, fcoe_destroy_work);
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/* configure fc_lport, e.g., em */
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rc = fcoe_lport_config(lport);
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@ -769,7 +773,6 @@ static struct fc_lport *fcoe_if_create(struct fcoe_interface *fcoe,
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goto out_lp_destroy;
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}
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dev_hold(netdev);
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fcoe_interface_get(fcoe);
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return lport;
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@ -1530,19 +1533,19 @@ static int fcoe_device_notification(struct notifier_block *notifier,
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struct fc_lport *lp = NULL;
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struct net_device *netdev = ptr;
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struct fcoe_interface *fcoe;
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struct fcoe_port *port;
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struct fcoe_dev_stats *stats;
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u32 link_possible = 1;
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u32 mfs;
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int rc = NOTIFY_OK;
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read_lock(&fcoe_hostlist_lock);
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write_lock(&fcoe_hostlist_lock);
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list_for_each_entry(fcoe, &fcoe_hostlist, list) {
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if (fcoe->netdev == netdev) {
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lp = fcoe->ctlr.lp;
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break;
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}
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}
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read_unlock(&fcoe_hostlist_lock);
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if (lp == NULL) {
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rc = NOTIFY_DONE;
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goto out;
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@ -1564,6 +1567,13 @@ static int fcoe_device_notification(struct notifier_block *notifier,
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break;
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case NETDEV_REGISTER:
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break;
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case NETDEV_UNREGISTER:
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list_del(&fcoe->list);
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port = lport_priv(fcoe->ctlr.lp);
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fcoe_interface_cleanup(fcoe);
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schedule_work(&port->destroy_work);
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goto out;
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break;
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default:
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FCOE_NETDEV_DBG(netdev, "Unknown event %ld "
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"from netdev netlink\n", event);
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@ -1576,6 +1586,7 @@ static int fcoe_device_notification(struct notifier_block *notifier,
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fcoe_clean_pending_queue(lp);
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}
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out:
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write_unlock(&fcoe_hostlist_lock);
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return rc;
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}
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@ -1600,75 +1611,6 @@ static struct net_device *fcoe_if_to_netdev(const char *buffer)
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return NULL;
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}
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/**
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* fcoe_netdev_to_module_owner() - finds out the driver module of the netdev
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* @netdev: the target netdev
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*
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* Returns: ptr to the struct module, NULL for failure
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*/
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static struct module *
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fcoe_netdev_to_module_owner(const struct net_device *netdev)
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{
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struct device *dev;
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if (!netdev)
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return NULL;
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dev = netdev->dev.parent;
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if (!dev)
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return NULL;
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if (!dev->driver)
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return NULL;
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return dev->driver->owner;
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}
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/**
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* fcoe_ethdrv_get() - Hold the Ethernet driver
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* @netdev: the target netdev
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*
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* Holds the Ethernet driver module by try_module_get() for
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* the corresponding netdev.
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*
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* Returns: 0 for success
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*/
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static int fcoe_ethdrv_get(const struct net_device *netdev)
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{
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struct module *owner;
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owner = fcoe_netdev_to_module_owner(netdev);
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if (owner) {
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FCOE_NETDEV_DBG(netdev, "Hold driver module %s\n",
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module_name(owner));
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return try_module_get(owner);
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}
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return -ENODEV;
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}
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/**
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* fcoe_ethdrv_put() - Release the Ethernet driver
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* @netdev: the target netdev
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*
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* Releases the Ethernet driver module by module_put for
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* the corresponding netdev.
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*
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* Returns: 0 for success
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*/
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static int fcoe_ethdrv_put(const struct net_device *netdev)
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{
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struct module *owner;
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owner = fcoe_netdev_to_module_owner(netdev);
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if (owner) {
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FCOE_NETDEV_DBG(netdev, "Release driver module %s\n",
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module_name(owner));
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module_put(owner);
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return 0;
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}
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return -ENODEV;
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}
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/**
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* fcoe_destroy() - handles the destroy from sysfs
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* @buffer: expected to be an eth if name
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@ -1678,10 +1620,8 @@ static int fcoe_ethdrv_put(const struct net_device *netdev)
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*/
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static int fcoe_destroy(const char *buffer, struct kernel_param *kp)
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{
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struct net_device *netdev;
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struct fcoe_interface *fcoe;
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struct fcoe_port *port;
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struct fc_lport *lport;
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struct net_device *netdev;
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int rc;
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mutex_lock(&fcoe_config_mutex);
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rc = -ENODEV;
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goto out_nodev;
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}
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/* look for existing lport */
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lport = fcoe_hostlist_lookup(netdev);
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if (!lport) {
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write_lock(&fcoe_hostlist_lock);
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fcoe = fcoe_hostlist_lookup_port(netdev);
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if (!fcoe) {
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write_unlock(&fcoe_hostlist_lock);
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rc = -ENODEV;
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goto out_putdev;
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}
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/* Remove the instance from fcoe's list */
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fcoe_hostlist_remove(lport);
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port = lport_priv(lport);
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fcoe = port->fcoe;
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fcoe_if_destroy(lport);
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fcoe_ethdrv_put(netdev);
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rc = 0;
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list_del(&fcoe->list);
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write_unlock(&fcoe_hostlist_lock);
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rtnl_lock();
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fcoe_interface_cleanup(fcoe);
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rtnl_unlock();
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fcoe_if_destroy(fcoe->ctlr.lp);
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out_putdev:
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dev_put(netdev);
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out_nodev:
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@ -1722,6 +1663,16 @@ out_nodev:
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return rc;
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}
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static void fcoe_destroy_work(struct work_struct *work)
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{
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struct fcoe_port *port;
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port = container_of(work, struct fcoe_port, destroy_work);
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mutex_lock(&fcoe_config_mutex);
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fcoe_if_destroy(port->lport);
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mutex_unlock(&fcoe_config_mutex);
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}
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/**
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* fcoe_create() - Handles the create call from sysfs
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* @buffer: expected to be an eth if name
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@ -1749,17 +1700,18 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp)
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}
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#endif
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rtnl_lock();
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netdev = fcoe_if_to_netdev(buffer);
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if (!netdev) {
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rc = -ENODEV;
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goto out_nodev;
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}
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/* look for existing lport */
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if (fcoe_hostlist_lookup(netdev)) {
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rc = -EEXIST;
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goto out_putdev;
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}
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fcoe_ethdrv_get(netdev);
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fcoe = fcoe_interface_create(netdev);
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if (!fcoe) {
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@ -1771,8 +1723,8 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp)
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if (IS_ERR(lport)) {
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printk(KERN_ERR "fcoe: Failed to create interface (%s)\n",
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netdev->name);
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fcoe_ethdrv_put(netdev);
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rc = -EIO;
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fcoe_interface_cleanup(fcoe);
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goto out_free;
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}
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@ -1798,6 +1750,7 @@ out_free:
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out_putdev:
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dev_put(netdev);
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out_nodev:
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rtnl_unlock();
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mutex_unlock(&fcoe_config_mutex);
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return rc;
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}
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@ -1972,25 +1925,6 @@ int fcoe_hostlist_add(const struct fc_lport *lport)
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return 0;
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}
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/**
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* fcoe_hostlist_remove() - remove a lport from lports list
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* @lp: ptr to the fc_lport to be removed
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*
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* Returns: 0 for success
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*/
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int fcoe_hostlist_remove(const struct fc_lport *lport)
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{
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struct fcoe_interface *fcoe;
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write_lock_bh(&fcoe_hostlist_lock);
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fcoe = fcoe_hostlist_lookup_port(fcoe_netdev(lport));
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BUG_ON(!fcoe);
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list_del(&fcoe->list);
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write_unlock_bh(&fcoe_hostlist_lock);
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return 0;
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}
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/**
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* fcoe_init() - fcoe module loading initialization
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*
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@ -2046,6 +1980,7 @@ static void __exit fcoe_exit(void)
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unsigned int cpu;
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struct fcoe_interface *fcoe, *tmp;
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LIST_HEAD(local_list);
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struct fcoe_port *port;
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mutex_lock(&fcoe_config_mutex);
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@ -2058,7 +1993,11 @@ static void __exit fcoe_exit(void)
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list_for_each_entry_safe(fcoe, tmp, &local_list, list) {
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list_del(&fcoe->list);
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fcoe_if_destroy(fcoe->ctlr.lp);
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port = lport_priv(fcoe->ctlr.lp);
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rtnl_lock();
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fcoe_interface_cleanup(fcoe);
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rtnl_unlock();
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schedule_work(&port->destroy_work);
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}
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unregister_hotcpu_notifier(&fcoe_cpu_notifier);
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@ -2066,9 +2005,14 @@ static void __exit fcoe_exit(void)
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for_each_online_cpu(cpu)
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fcoe_percpu_thread_destroy(cpu);
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/* detach from scsi transport */
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fcoe_if_exit();
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mutex_unlock(&fcoe_config_mutex);
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/* flush any asyncronous interface destroys,
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* this should happen after the netdev notifier is unregistered */
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flush_scheduled_work();
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/* detach from scsi transport
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* must happen after all destroys are done, therefor after the flush */
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fcoe_if_exit();
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}
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module_exit(fcoe_exit);
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@ -93,9 +93,11 @@ struct fcoe_interface {
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*/
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struct fcoe_port {
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struct fcoe_interface *fcoe;
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struct fc_lport *lport;
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struct sk_buff_head fcoe_pending_queue;
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u8 fcoe_pending_queue_active;
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struct timer_list timer; /* queue timer */
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struct work_struct destroy_work; /* to prevent rtnl deadlocks */
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};
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#define fcoe_from_ctlr(fip) container_of(fip, struct fcoe_interface, ctlr)
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