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Commit f9184df3 authored by Neil Horman's avatar Neil Horman Committed by Robert Love
Browse files

fcoe: close race on link speed detection in fcoe code 



When creating an fcoe interfce, we call fcoe_link_speed_update before we add the
lports fcoe interface to the fc_hostlist.  Since network device events like
NETDEV_CHANGE are only processed if an fcoe interface is found with an
underlying netdev that matches the netdev of the event.  Since this processing
in fcoe_device_notification is how link_speed changes get communicated to the
libfc  code (via fcoe_link_speed_update), we have a race condition - if a
NETDEV_CHANGE event is sent after the call to fcoe_link_speed_update in
fcoe_netdev_config, but before we add the interface to the fc_hostlist, we will
loose the event and attributes like /sys/class/fc_host/hostX/speed will not get
updated properly.

Fix this by moving the add to the fc_hostlist above the serialized call to
fcoe_netdev_config, ensuring that we catch netdev envents before we make a
direct call to fcoe_link_speed_update.

Also use this opportunity to clean up access to the fc_hostlist a bit by
creating a fcoe_hostlist_del accessor and replacing the cleanup in fcoe_exit to
use it properly.

Tested by myself successfully

[ Comment over 80 chars broken into multi-line by Robert Love to
  satisfy checkpatch.pl ]

Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Reviewed-by: default avatarYi Zou <yi.zou@intel.com>
Signed-off-by: default avatarRobert Love <robert.w.love@intel.com>
parent cf028200

drivers/scsi/fcoe/fcoe.c

+27 −4
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ static int fcoe_link_ok(struct fc_lport *); 


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

static int fcoe_hostlist_add(const struct fc_lport *);

static void fcoe_hostlist_del(const struct fc_lport *);



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

static void fcoe_dev_setup(void);
@@ -1119,6 +1120,12 @@ static struct fc_lport *fcoe_if_create(struct fcoe_interface *fcoe, 
	port->min_queue_depth = FCOE_MIN_QUEUE_DEPTH;

	INIT_WORK(&port->destroy_work, fcoe_destroy_work);



	/*

	 * Need to add the lport to the hostlist

	 * so we catch NETDEV_CHANGE events.

	 */

	fcoe_hostlist_add(lport);



	/* configure a fc_lport including the exchange manager */

	rc = fcoe_lport_config(lport);

	if (rc) {
@@ -1190,6 +1197,7 @@ static struct fc_lport *fcoe_if_create(struct fcoe_interface *fcoe, 
out_lp_destroy:

	fc_exch_mgr_free(lport);

out_host_put:

	fcoe_hostlist_del(lport);

	scsi_host_put(lport->host);

out:

	return ERR_PTR(rc);
@@ -2313,9 +2321,6 @@ static int _fcoe_create(struct net_device *netdev, enum fip_state fip_mode, 
	/* setup DCB priority attributes. */

	fcoe_dcb_create(fcoe);



	/* add to lports list */

	fcoe_hostlist_add(lport);



	/* start FIP Discovery and FLOGI */

	lport->boot_time = jiffies;

	fc_fabric_login(lport);
@@ -2523,6 +2528,24 @@ static int fcoe_hostlist_add(const struct fc_lport *lport) 
	return 0;

}



/**

 * fcoe_hostlist_del() - Remove the FCoE interface identified by a local

 *			 port to the hostlist

 * @lport: The local port that identifies the FCoE interface to be added

 *

 * Locking: must be called with the RTNL mutex held

 *

 */

static void fcoe_hostlist_del(const struct fc_lport *lport)

{

	struct fcoe_interface *fcoe;

	struct fcoe_port *port;



	port = lport_priv(lport);

	fcoe = port->priv;

	list_del(&fcoe->list);

	return;

}



static struct fcoe_transport fcoe_sw_transport = {

	.name = {FCOE_TRANSPORT_DEFAULT},
@@ -2613,9 +2636,9 @@ static void __exit fcoe_exit(void) 
	/* releases the associated fcoe hosts */

	rtnl_lock();

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

		list_del(&fcoe->list);

		ctlr = fcoe_to_ctlr(fcoe);

		port = lport_priv(ctlr->lp);

		fcoe_hostlist_del(port->lport);

		queue_work(fcoe_wq, &port->destroy_work);

	}

	rtnl_unlock();