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: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c
index 0b33368..d605700 100644
--- a/drivers/scsi/fcoe/fcoe.c
+++ b/drivers/scsi/fcoe/fcoe.c
@@ -86,6 +86,7 @@
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 @@
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 @@
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 @@
/* 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 @@
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 @@
/* 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();