[SCSI] fcoe: use rtnl mutex in place of hostlist lock

This just cuts down on the number of locks we're dealing with, and
eliminates the need to take another lock in the netdev notifier.
Signed-off-by: Chris Leech <christopher.leech@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/fcoe/fcoe.c

@@ -58,8 +58,8 @@ MODULE_PARM_DESC(ddp_min, "Minimum I/O size in bytes for "	\
 DEFINE_MUTEX(fcoe_config_mutex);
 
 /* fcoe host list */
+/* must only by accessed under the RTNL mutex */
 LIST_HEAD(fcoe_hostlist);
-DEFINE_RWLOCK(fcoe_hostlist_lock);
 DEFINE_PER_CPU(struct fcoe_percpu_s, fcoe_percpu);
 
 /* Function Prototypes */
@@ -527,8 +527,6 @@ bool fcoe_oem_match(struct fc_frame *fp)
  * fcoe_em_config() - allocates em for this lport
  * @lp: the fcoe that em is to allocated for
  *
- * Called with write fcoe_hostlist_lock held.
- *
  * Returns : 0 on success
  */
 static inline int fcoe_em_config(struct fc_lport *lp)
@@ -1539,7 +1537,6 @@ static int fcoe_device_notification(struct notifier_block *notifier,
 	u32 mfs;
 	int rc = NOTIFY_OK;
 
-	write_lock(&fcoe_hostlist_lock);
 	list_for_each_entry(fcoe, &fcoe_hostlist, list) {
 		if (fcoe->netdev == netdev) {
 			lp = fcoe->ctlr.lp;
@@ -1586,7 +1583,6 @@ static int fcoe_device_notification(struct notifier_block *notifier,
 		fcoe_clean_pending_queue(lp);
 	}
 out:
-	write_unlock(&fcoe_hostlist_lock);
 	return rc;
 }
 
@@ -1643,16 +1639,14 @@ static int fcoe_destroy(const char *buffer, struct kernel_param *kp)
 		goto out_nodev;
 	}
 
-	write_lock(&fcoe_hostlist_lock);
+	rtnl_lock();
 	fcoe = fcoe_hostlist_lookup_port(netdev);
 	if (!fcoe) {
-		write_unlock(&fcoe_hostlist_lock);
+		rtnl_unlock();
 		rc = -ENODEV;
 		goto out_putdev;
 	}
 	list_del(&fcoe->list);
-	write_unlock(&fcoe_hostlist_lock);
-	rtnl_lock();
 	fcoe_interface_cleanup(fcoe);
 	rtnl_unlock();
 	fcoe_if_destroy(fcoe->ctlr.lp);
@@ -1870,9 +1864,8 @@ int fcoe_reset(struct Scsi_Host *shost)
  * fcoe_hostlist_lookup_port() - find the corresponding lport by a given device
  * @dev: this is currently ptr to net_device
  *
- * Called with fcoe_hostlist_lock held.
- *
  * Returns: NULL or the located fcoe_port
+ * Locking: must be called with the RNL mutex held
  */
 static struct fcoe_interface *
 fcoe_hostlist_lookup_port(const struct net_device *dev)
@@ -1891,15 +1884,13 @@ fcoe_hostlist_lookup_port(const struct net_device *dev)
  * @netdev: ptr to net_device
  *
  * Returns: 0 for success
+ * Locking: must be called with the RTNL mutex held
  */
-struct fc_lport *fcoe_hostlist_lookup(const struct net_device *netdev)
+static struct fc_lport *fcoe_hostlist_lookup(const struct net_device *netdev)
 {
 	struct fcoe_interface *fcoe;
 
-	read_lock(&fcoe_hostlist_lock);
 	fcoe = fcoe_hostlist_lookup_port(netdev);
-	read_unlock(&fcoe_hostlist_lock);
-
 	return (fcoe) ? fcoe->ctlr.lp : NULL;
 }
 
@@ -1908,20 +1899,19 @@ struct fc_lport *fcoe_hostlist_lookup(const struct net_device *netdev)
  * @lp: ptr to the fc_lport to be added
  *
  * Returns: 0 for success
+ * Locking: must be called with the RTNL mutex held
  */
-int fcoe_hostlist_add(const struct fc_lport *lport)
+static int fcoe_hostlist_add(const struct fc_lport *lport)
 {
 	struct fcoe_interface *fcoe;
 	struct fcoe_port *port;
 
-	write_lock_bh(&fcoe_hostlist_lock);
 	fcoe = fcoe_hostlist_lookup_port(fcoe_netdev(lport));
 	if (!fcoe) {
 		port = lport_priv(lport);
 		fcoe = port->fcoe;
 		list_add_tail(&fcoe->list, &fcoe_hostlist);
 	}
-	write_unlock_bh(&fcoe_hostlist_lock);
 	return 0;
 }
 
@@ -1979,7 +1969,6 @@ 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);
@@ -1987,18 +1976,14 @@ static void __exit fcoe_exit(void)
 	fcoe_dev_cleanup();
 
 	/* releases the associated fcoe hosts */
-	write_lock_bh(&fcoe_hostlist_lock);
-	list_splice_init(&fcoe_hostlist, &local_list);
-	write_unlock_bh(&fcoe_hostlist_lock);
-
-	list_for_each_entry_safe(fcoe, tmp, &local_list, list) {
+	rtnl_lock();
+	list_for_each_entry_safe(fcoe, tmp, &fcoe_hostlist, list) {
 		list_del(&fcoe->list);
 		port = lport_priv(fcoe->ctlr.lp);
-		rtnl_lock();
 		fcoe_interface_cleanup(fcoe);
-		rtnl_unlock();
 		schedule_work(&port->destroy_work);
 	}
+	rtnl_unlock();
 
 	unregister_hotcpu_notifier(&fcoe_cpu_notifier);