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. CC: John Fastabend <[email protected]> Signed-off-by: Chris Leech <[email protected]> --- drivers/scsi/fcoe/fcoe.c | 132 ++++++++++++++-------------------------------- drivers/scsi/fcoe/fcoe.h | 1 2 files changed, 41 insertions(+), 92 deletions(-) diff --git a/drivers/scsi/fcoe/fcoe.c b/drivers/scsi/fcoe/fcoe.c index c41fd16..be7f2c3 100644 --- a/drivers/scsi/fcoe/fcoe.c +++ b/drivers/scsi/fcoe/fcoe.c @@ -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_interface_destroy_work(struct work_struct *work); /** * fcoe_interface_create() @@ -232,7 +233,9 @@ static struct fcoe_interface *fcoe_interface_create(struct net_device *netdev) return NULL; } + dev_hold(netdev); kref_init(&fcoe->kref); + INIT_WORK(&fcoe->destroy_work, fcoe_interface_destroy_work); /* * Initialize FIP. @@ -279,10 +282,13 @@ 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); + netdev = fcoe->real_dev; fcoe_interface_cleanup(fcoe); kfree(fcoe); + dev_put(netdev); } /** @@ -625,8 +631,7 @@ 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(fcoe->real_dev); + /* Release the Scsi_Host */ scsi_host_put(lport->host); fcoe_interface_put(fcoe); } @@ -753,7 +758,6 @@ static struct fc_lport *fcoe_if_create(struct fcoe_interface *fcoe, goto out_lp_destroy; } - dev_hold(netdev); fcoe_interface_get(fcoe); return lport; @@ -1552,6 +1556,10 @@ static int fcoe_device_notification(struct notifier_block *notifier, break; case NETDEV_REGISTER: break; + case NETDEV_UNREGISTER: + schedule_work(&fcoe->destroy_work); + goto out; + break; default: FCOE_NETDEV_DBG(real_dev, "Unknown event %ld " "from netdev netlink\n", event); @@ -1588,73 +1596,18 @@ 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) +static int __fcoe_destroy(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; + struct fc_lport *lport; - 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; + /* look for existing lport */ + lport = fcoe_hostlist_lookup(netdev); + if (!lport) + return -ENODEV; + /* Remove the instance from fcoe's list */ + fcoe_hostlist_remove(lport); + fcoe_if_destroy(lport); + return 0; } /** @@ -1667,9 +1620,6 @@ 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; int rc; mutex_lock(&fcoe_create_mutex); @@ -1683,26 +1633,24 @@ 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) { - 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; -out_putdev: + + rc = __fcoe_destroy(netdev); dev_put(netdev); out_nodev: mutex_unlock(&fcoe_create_mutex); return rc; } +static void fcoe_interface_destroy_work(struct work_struct *work) +{ + struct fcoe_interface *fcoe; + + fcoe = container_of(work, struct fcoe_interface, destroy_work); + mutex_lock(&fcoe_create_mutex); + __fcoe_destroy(fcoe->real_dev); + mutex_unlock(&fcoe_create_mutex); +} + /** * fcoe_create() - Handles the create call from sysfs * @buffer: expected to be an eth if name @@ -1728,12 +1676,12 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp) 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) { @@ -1745,7 +1693,6 @@ 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; goto out_free; } @@ -1762,11 +1709,12 @@ static int fcoe_create(const char *buffer, struct kernel_param *kp) if (!fcoe_link_ok(lport)) fcoe_ctlr_link_up(&fcoe->ctlr); - dev_put(netdev); - mutex_unlock(&fcoe_create_mutex); - return 0; - + rc = 0; out_free: + /* + * Release from init in fcoe_interface_create(), on success lport + * should be holding a reference taken in fcoe_if_create(). + */ fcoe_interface_put(fcoe); out_putdev: dev_put(netdev); @@ -2023,7 +1971,7 @@ static void __exit fcoe_exit(void) /* releases the associated fcoe hosts */ list_for_each_entry_safe(fcoe, tmp, &fcoe_hostlist, list) - fcoe_if_destroy(fcoe->ctlr.lp); + __fcoe_destroy(fcoe->real_dev); unregister_hotcpu_notifier(&fcoe_cpu_notifier); diff --git a/drivers/scsi/fcoe/fcoe.h b/drivers/scsi/fcoe/fcoe.h index 9781f58..70917ec 100644 --- a/drivers/scsi/fcoe/fcoe.h +++ b/drivers/scsi/fcoe/fcoe.h @@ -86,6 +86,7 @@ struct fcoe_interface { struct fcoe_ctlr ctlr; struct fc_exch_mgr *oem; /* offload exchange manger */ struct kref kref; + struct work_struct destroy_work; /* to prevent rtnl deadlocks */ }; /* _______________________________________________ devel mailing list [email protected] http://www.open-fcoe.org/mailman/listinfo/devel
