From f9184df3b99375964340c1a78e33f304bbf15f06 Mon Sep 17 00:00:00 2001 From: Neil Horman Date: Tue, 15 Jan 2013 14:34:40 -0500 Subject: [PATCH] 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 Reviewed-by: Yi Zou Signed-off-by: Robert Love --- drivers/scsi/fcoe/fcoe.c | 31 +++++++++++++++++++++++++++---- 1 file changed, 27 insertions(+), 4 deletions(-) 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 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(); -- 2.7.4