Commit 2e70e241 authored by Chris Leech's avatar Chris Leech Committed by James Bottomley
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[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: default avatarChris Leech <christopher.leech@intel.com>
Signed-off-by: default avatarRobert Love <robert.w.love@intel.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent c863df33

drivers/scsi/fcoe/fcoe.c

+65 −121
Original line number Diff line number Diff line
@@ -74,12 +74,13 @@ static int fcoe_link_ok(struct fc_lport *lp); 


static struct fc_lport *fcoe_hostlist_lookup(const struct net_device *);

static int fcoe_hostlist_add(const struct fc_lport *);

static int fcoe_hostlist_remove(const struct fc_lport *);



static void fcoe_check_wait_queue(struct fc_lport *, struct sk_buff *);

static int fcoe_device_notification(struct notifier_block *, ulong, void *);

static void fcoe_dev_setup(void);

static void fcoe_dev_cleanup(void);

static struct fcoe_interface *

	fcoe_hostlist_lookup_port(const struct net_device *dev);



/* notification function from net device */

static struct notifier_block fcoe_notifier = {
@@ -149,6 +150,7 @@ static int fcoe_fip_recv(struct sk_buff *skb, struct net_device *dev, 
 * @netdev : ptr to the associated netdevice struct

 *

 * Returns : 0 for success

 * Locking: must be called with the RTNL mutex held

 */

static int fcoe_interface_setup(struct fcoe_interface *fcoe,

				struct net_device *netdev)
@@ -188,13 +190,11 @@ static int fcoe_interface_setup(struct fcoe_interface *fcoe, 
	 * or enter promiscuous mode if not capable of listening

	 * for multiple unicast MACs.

	 */

	rtnl_lock();

	memcpy(flogi_maddr, (u8[6]) FC_FCOE_FLOGI_MAC, ETH_ALEN);

	dev_unicast_add(netdev, flogi_maddr);

	if (fip->spma)

		dev_unicast_add(netdev, fip->ctl_src_addr);

	dev_mc_add(netdev, FIP_ALL_ENODE_MACS, ETH_ALEN, 0);

	rtnl_unlock();



	/*

	 * setup the receive function from ethernet driver
@@ -215,6 +215,7 @@ static int fcoe_interface_setup(struct fcoe_interface *fcoe, 


static void fcoe_fip_send(struct fcoe_ctlr *fip, struct sk_buff *skb);

static void fcoe_update_src_mac(struct fcoe_ctlr *fip, u8 *old, u8 *new);

static void fcoe_destroy_work(struct work_struct *work);



/**

 * fcoe_interface_create()
@@ -232,6 +233,7 @@ static struct fcoe_interface *fcoe_interface_create(struct net_device *netdev) 
		return NULL;

	}



	dev_hold(netdev);

	kref_init(&fcoe->kref);



	/*
@@ -249,6 +251,8 @@ static struct fcoe_interface *fcoe_interface_create(struct net_device *netdev) 
/**

 * fcoe_interface_cleanup() - clean up netdev configurations

 * @fcoe:

 *

 * Caller must be holding the RTNL mutex

 */

void fcoe_interface_cleanup(struct fcoe_interface *fcoe)

{
@@ -266,11 +270,7 @@ void fcoe_interface_cleanup(struct fcoe_interface *fcoe) 
	__dev_remove_pack(&fcoe->fip_packet_type);

	synchronize_net();



	/* tear-down the FCoE controller */

	fcoe_ctlr_destroy(&fcoe->ctlr);



	/* Delete secondary MAC addresses */

	rtnl_lock();

	memcpy(flogi_maddr, (u8[6]) FC_FCOE_FLOGI_MAC, ETH_ALEN);

	dev_unicast_delete(netdev, flogi_maddr);

	if (!is_zero_ether_addr(fip->data_src_addr))
@@ -278,7 +278,6 @@ void fcoe_interface_cleanup(struct fcoe_interface *fcoe) 
	if (fip->spma)

		dev_unicast_delete(netdev, fip->ctl_src_addr);

	dev_mc_delete(netdev, FIP_ALL_ENODE_MACS, ETH_ALEN, 0);

	rtnl_unlock();

}



/**
@@ -288,10 +287,14 @@ void fcoe_interface_cleanup(struct fcoe_interface *fcoe) 
static void fcoe_interface_release(struct kref *kref)

{

	struct fcoe_interface *fcoe;

	struct net_device *netdev;



	fcoe = container_of(kref, struct fcoe_interface, kref);

	fcoe_interface_cleanup(fcoe);

	netdev = fcoe->netdev;

	/* tear-down the FCoE controller */

	fcoe_ctlr_destroy(&fcoe->ctlr);

	kfree(fcoe);

	dev_put(netdev);

}



/**
@@ -642,8 +645,7 @@ static void fcoe_if_destroy(struct fc_lport *lport) 
	/* Free memory used by statistical counters */

	fc_lport_free_stats(lport);



	/* Release the net_device and Scsi_Host */

	dev_put(netdev);

	/* Release the Scsi_Host */

	scsi_host_put(lport->host);

}
@@ -718,7 +720,9 @@ static struct fc_lport *fcoe_if_create(struct fcoe_interface *fcoe, 
	}

	lport = shost_priv(shost);

	port = lport_priv(lport);

	port->lport = lport;

	port->fcoe = fcoe;

	INIT_WORK(&port->destroy_work, fcoe_destroy_work);



	/* configure fc_lport, e.g., em */

	rc = fcoe_lport_config(lport);
@@ -769,7 +773,6 @@ static struct fc_lport *fcoe_if_create(struct fcoe_interface *fcoe, 
		goto out_lp_destroy;

	}



	dev_hold(netdev);

	fcoe_interface_get(fcoe);

	return lport;
@@ -1530,19 +1533,19 @@ static int fcoe_device_notification(struct notifier_block *notifier, 
	struct fc_lport *lp = NULL;

	struct net_device *netdev = ptr;

	struct fcoe_interface *fcoe;

	struct fcoe_port *port;

	struct fcoe_dev_stats *stats;

	u32 link_possible = 1;

	u32 mfs;

	int rc = NOTIFY_OK;



	read_lock(&fcoe_hostlist_lock);

	write_lock(&fcoe_hostlist_lock);

	list_for_each_entry(fcoe, &fcoe_hostlist, list) {

		if (fcoe->netdev == netdev) {

			lp = fcoe->ctlr.lp;

			break;

		}

	}

	read_unlock(&fcoe_hostlist_lock);

	if (lp == NULL) {

		rc = NOTIFY_DONE;

		goto out;
@@ -1564,6 +1567,13 @@ static int fcoe_device_notification(struct notifier_block *notifier, 
		break;

	case NETDEV_REGISTER:

		break;

	case NETDEV_UNREGISTER:

		list_del(&fcoe->list);

		port = lport_priv(fcoe->ctlr.lp);

		fcoe_interface_cleanup(fcoe);

		schedule_work(&port->destroy_work);

		goto out;

		break;

	default:

		FCOE_NETDEV_DBG(netdev, "Unknown event %ld "

				"from netdev netlink\n", event);
@@ -1576,6 +1586,7 @@ static int fcoe_device_notification(struct notifier_block *notifier, 
		fcoe_clean_pending_queue(lp);

	}

out:

	write_unlock(&fcoe_hostlist_lock);

	return rc;

}
@@ -1600,75 +1611,6 @@ static struct net_device *fcoe_if_to_netdev(const char *buffer) 
	return NULL;

}



/**

 * fcoe_netdev_to_module_owner() - finds out the driver module of the netdev

 * @netdev: the target netdev

 *

 * Returns: ptr to the struct module, NULL for failure

 */

static struct module *

fcoe_netdev_to_module_owner(const struct net_device *netdev)

{

	struct device *dev;



	if (!netdev)

		return NULL;



	dev = netdev->dev.parent;

	if (!dev)

		return NULL;



	if (!dev->driver)

		return NULL;



	return dev->driver->owner;

}



/**

 * fcoe_ethdrv_get() - Hold the Ethernet driver

 * @netdev: the target netdev

 *

 * Holds the Ethernet driver module by try_module_get() for

 * the corresponding netdev.

 *

 * Returns: 0 for success

 */

static int fcoe_ethdrv_get(const struct net_device *netdev)

{

	struct module *owner;



	owner = fcoe_netdev_to_module_owner(netdev);

	if (owner) {

		FCOE_NETDEV_DBG(netdev, "Hold driver module %s\n",

				module_name(owner));

		return  try_module_get(owner);

	}

	return -ENODEV;

}



/**

 * fcoe_ethdrv_put() - Release the Ethernet driver

 * @netdev: the target netdev

 *

 * Releases the Ethernet driver module by module_put for

 * the corresponding netdev.

 *

 * Returns: 0 for success

 */

static int fcoe_ethdrv_put(const struct net_device *netdev)

{

	struct module *owner;



	owner = fcoe_netdev_to_module_owner(netdev);

	if (owner) {

		FCOE_NETDEV_DBG(netdev, "Release driver module %s\n",

				module_name(owner));

		module_put(owner);

		return 0;

	}

	return -ENODEV;

}



/**

 * fcoe_destroy() - handles the destroy from sysfs

 * @buffer: expected to be an eth if name
@@ -1678,10 +1620,8 @@ static int fcoe_ethdrv_put(const struct net_device *netdev) 
 */

static int fcoe_destroy(const char *buffer, struct kernel_param *kp)

{

	struct net_device *netdev;

	struct fcoe_interface *fcoe;

	struct fcoe_port *port;

	struct fc_lport *lport;

	struct net_device *netdev;

	int rc;



	mutex_lock(&fcoe_config_mutex);
@@ -1702,19 +1642,20 @@ static int fcoe_destroy(const char *buffer, struct kernel_param *kp) 
		rc = -ENODEV;

		goto out_nodev;

	}

	/* look for existing lport */

	lport = fcoe_hostlist_lookup(netdev);

	if (!lport) {



	write_lock(&fcoe_hostlist_lock);

	fcoe = fcoe_hostlist_lookup_port(netdev);

	if (!fcoe) {

		write_unlock(&fcoe_hostlist_lock);

		rc = -ENODEV;

		goto out_putdev;

	}

	/* Remove the instance from fcoe's list */

	fcoe_hostlist_remove(lport);

	port = lport_priv(lport);

	fcoe = port->fcoe;

	fcoe_if_destroy(lport);

	fcoe_ethdrv_put(netdev);

	rc = 0;

	list_del(&fcoe->list);

	write_unlock(&fcoe_hostlist_lock);

	rtnl_lock();

	fcoe_interface_cleanup(fcoe);

	rtnl_unlock();

	fcoe_if_destroy(fcoe->ctlr.lp);

out_putdev:

	dev_put(netdev);

out_nodev:
@@ -1722,6 +1663,16 @@ out_nodev: 
	return rc;

}



static void fcoe_destroy_work(struct work_struct *work)

{

	struct fcoe_port *port;



	port = container_of(work, struct fcoe_port, destroy_work);

	mutex_lock(&fcoe_config_mutex);

	fcoe_if_destroy(port->lport);

	mutex_unlock(&fcoe_config_mutex);

}



/**

 * fcoe_create() - Handles the create call from sysfs

 * @buffer: expected to be an eth if name
@@ -1749,17 +1700,18 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp) 
	}

#endif



	rtnl_lock();

	netdev = fcoe_if_to_netdev(buffer);

	if (!netdev) {

		rc = -ENODEV;

		goto out_nodev;

	}



	/* look for existing lport */

	if (fcoe_hostlist_lookup(netdev)) {

		rc = -EEXIST;

		goto out_putdev;

	}

	fcoe_ethdrv_get(netdev);



	fcoe = fcoe_interface_create(netdev);

	if (!fcoe) {
@@ -1771,8 +1723,8 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp) 
	if (IS_ERR(lport)) {

		printk(KERN_ERR "fcoe: Failed to create interface (%s)\n",

		       netdev->name);

		fcoe_ethdrv_put(netdev);

		rc = -EIO;

		fcoe_interface_cleanup(fcoe);

		goto out_free;

	}
@@ -1798,6 +1750,7 @@ out_free: 
out_putdev:

	dev_put(netdev);

out_nodev:

	rtnl_unlock();

	mutex_unlock(&fcoe_config_mutex);

	return rc;

}
@@ -1972,25 +1925,6 @@ int fcoe_hostlist_add(const struct fc_lport *lport) 
	return 0;

}



/**

 * fcoe_hostlist_remove() - remove a lport from lports list

 * @lp: ptr to the fc_lport to be removed

 *

 * Returns: 0 for success

 */

int fcoe_hostlist_remove(const struct fc_lport *lport)

{

	struct fcoe_interface *fcoe;



	write_lock_bh(&fcoe_hostlist_lock);

	fcoe = fcoe_hostlist_lookup_port(fcoe_netdev(lport));

	BUG_ON(!fcoe);

	list_del(&fcoe->list);

	write_unlock_bh(&fcoe_hostlist_lock);



	return 0;

}



/**

 * fcoe_init() - fcoe module loading initialization

 *
@@ -2046,6 +1980,7 @@ static void __exit fcoe_exit(void) 
	unsigned int cpu;

	struct fcoe_interface *fcoe, *tmp;

	LIST_HEAD(local_list);

	struct fcoe_port *port;



	mutex_lock(&fcoe_config_mutex);
@@ -2058,7 +1993,11 @@ static void __exit fcoe_exit(void) 


	list_for_each_entry_safe(fcoe, tmp, &local_list, list) {

		list_del(&fcoe->list);

		fcoe_if_destroy(fcoe->ctlr.lp);

		port = lport_priv(fcoe->ctlr.lp);

		rtnl_lock();

		fcoe_interface_cleanup(fcoe);

		rtnl_unlock();

		schedule_work(&port->destroy_work);

	}



	unregister_hotcpu_notifier(&fcoe_cpu_notifier);
@@ -2066,9 +2005,14 @@ static void __exit fcoe_exit(void) 
	for_each_online_cpu(cpu)

		fcoe_percpu_thread_destroy(cpu);



	/* detach from scsi transport */

	fcoe_if_exit();



	mutex_unlock(&fcoe_config_mutex);



	/* flush any asyncronous interface destroys,

	 * this should happen after the netdev notifier is unregistered */

	flush_scheduled_work();



	/* detach from scsi transport

	 * must happen after all destroys are done, therefor after the flush */

	fcoe_if_exit();

}

module_exit(fcoe_exit);

drivers/scsi/fcoe/fcoe.h

+2 −0
Original line number Diff line number Diff line
@@ -93,9 +93,11 @@ struct fcoe_interface { 
 */

struct fcoe_port {

	struct fcoe_interface *fcoe;

	struct fc_lport *lport;

	struct sk_buff_head fcoe_pending_queue;

	u8	fcoe_pending_queue_active;

	struct timer_list timer;		/* queue timer */

	struct work_struct destroy_work;	/* to prevent rtnl deadlocks */

};



#define fcoe_from_ctlr(fip) container_of(fip, struct fcoe_interface, ctlr)

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