[ATM]: lane and mpoa module refcounting and locking cleanup.

net/atm/common.c

@@ -32,21 +32,61 @@
 #include <linux/atmlec.h>
 #include "lec.h"
 #include "lec_arpc.h"
-struct atm_lane_ops atm_lane_ops;
-#endif
-#ifdef CONFIG_ATM_LANE_MODULE
+struct atm_lane_ops *atm_lane_ops;
+static DECLARE_MUTEX(atm_lane_ops_mutex);
+
+void atm_lane_ops_set(struct atm_lane_ops *hook)
+{
+	down(&atm_lane_ops_mutex);
+	atm_lane_ops = hook;
+	up(&atm_lane_ops_mutex);
+}
+
+int try_atm_lane_ops(void)
+{
+	down(&atm_lane_ops_mutex);
+	if (atm_lane_ops && try_module_get(atm_lane_ops->owner)) {
+		up(&atm_lane_ops_mutex);
+		return 1;
+	}
+	up(&atm_lane_ops_mutex);
+	return 0;
+}
+
+#if defined(CONFIG_ATM_LANE_MODULE) || defined(CONFIG_ATM_MPOA_MODULE)
 EXPORT_SYMBOL(atm_lane_ops);
+EXPORT_SYMBOL(try_atm_lane_ops);
+EXPORT_SYMBOL(atm_lane_ops_set);
+#endif
 #endif
 
 #if defined(CONFIG_ATM_MPOA) || defined(CONFIG_ATM_MPOA_MODULE)
 #include <linux/atmmpc.h>
 #include "mpc.h"
-struct atm_mpoa_ops atm_mpoa_ops;
-#endif
+struct atm_mpoa_ops *atm_mpoa_ops;
+static DECLARE_MUTEX(atm_mpoa_ops_mutex);
+
+void atm_mpoa_ops_set(struct atm_mpoa_ops *hook)
+{
+	down(&atm_mpoa_ops_mutex);
+	atm_mpoa_ops = hook;
+	up(&atm_mpoa_ops_mutex);
+}
+
+int try_atm_mpoa_ops(void)
+{
+	down(&atm_mpoa_ops_mutex);
+	if (atm_mpoa_ops && try_module_get(atm_mpoa_ops->owner)) {
+		up(&atm_mpoa_ops_mutex);
+		return 1;
+	}
+	up(&atm_mpoa_ops_mutex);
+	return 0;
+}
 #ifdef CONFIG_ATM_MPOA_MODULE
 EXPORT_SYMBOL(atm_mpoa_ops);
-#ifndef CONFIG_ATM_LANE_MODULE
-EXPORT_SYMBOL(atm_lane_ops);
+EXPORT_SYMBOL(try_atm_mpoa_ops);
+EXPORT_SYMBOL(atm_mpoa_ops_set);
 #endif
 #endif
 
@@ -728,27 +768,40 @@ int atm_ioctl(struct socket *sock,unsigned int cmd,unsigned long arg)
 				ret_val = -EPERM;
 				goto done;
 			}
-                        if (atm_lane_ops.lecd_attach == NULL)
-				atm_lane_init();
-                        if (atm_lane_ops.lecd_attach == NULL) { /* try again */
+#if defined(CONFIG_ATM_LANE_MODULE)
+                        if (!atm_lane_ops)
+				request_module("lec");
+#endif
+			if (try_atm_lane_ops()) {
+				error = atm_lane_ops->lecd_attach(vcc, (int) arg);
+				module_put(atm_lane_ops->owner);
+				if (error >= 0)
+					sock->state = SS_CONNECTED;
+				ret_val =  error;
+			} else
 				ret_val = -ENOSYS;
-				goto done;
-			}
-			error = atm_lane_ops.lecd_attach(vcc, (int)arg);
-			if (error >= 0) sock->state = SS_CONNECTED;
-			ret_val =  error;
 			goto done;
                 case ATMLEC_MCAST:
-			if (!capable(CAP_NET_ADMIN))
+			if (!capable(CAP_NET_ADMIN)) {
 				ret_val = -EPERM;
-			else
-				ret_val = atm_lane_ops.mcast_attach(vcc, (int)arg);
+				goto done;
+			}
+			if (try_atm_lane_ops()) {
+				ret_val = atm_lane_ops->mcast_attach(vcc, (int) arg);
+				module_put(atm_lane_ops->owner);
+			} else
+				ret_val = -ENOSYS;
 			goto done;
                 case ATMLEC_DATA:
-			if (!capable(CAP_NET_ADMIN))
+			if (!capable(CAP_NET_ADMIN)) {
 				ret_val = -EPERM;
-			else
-				ret_val = atm_lane_ops.vcc_attach(vcc, (void*)arg);
+				goto done;
+			}
+			if (try_atm_lane_ops()) {
+				ret_val = atm_lane_ops->vcc_attach(vcc, (void *) arg);
+				module_put(atm_lane_ops->owner);
+			} else
+				ret_val = -ENOSYS;
 			goto done;
 #endif
 #if defined(CONFIG_ATM_MPOA) || defined(CONFIG_ATM_MPOA_MODULE)
@@ -757,21 +810,29 @@ int atm_ioctl(struct socket *sock,unsigned int cmd,unsigned long arg)
 				ret_val = -EPERM;
 				goto done;
 			}
-			if (atm_mpoa_ops.mpoad_attach == NULL)
-                                atm_mpoa_init();
-			if (atm_mpoa_ops.mpoad_attach == NULL) { /* try again */
+#if defined(CONFIG_ATM_MPOA_MODULE)
+			if (!atm_mpoa_ops)
+                                request_module("mpoa");
+#endif
+			if (try_atm_mpoa_ops()) {
+				error = atm_mpoa_ops->mpoad_attach(vcc, (int) arg);
+				module_put(atm_mpoa_ops->owner);
+				if (error >= 0)
+					sock->state = SS_CONNECTED;
+				ret_val = error;
+			} else
 				ret_val = -ENOSYS;
-				goto done;
-			}
-			error = atm_mpoa_ops.mpoad_attach(vcc, (int)arg);
-			if (error >= 0) sock->state = SS_CONNECTED;
-			ret_val = error;
 			goto done;
 		case ATMMPC_DATA:
-			if (!capable(CAP_NET_ADMIN)) 
+			if (!capable(CAP_NET_ADMIN)) {
 				ret_val = -EPERM;
-			else
-				ret_val = atm_mpoa_ops.vcc_attach(vcc, arg);
+				goto done;
+			}
+			if (try_atm_mpoa_ops()) {
+				ret_val = atm_mpoa_ops->vcc_attach(vcc, arg);
+				module_put(atm_mpoa_ops->owner);
+			} else
+				ret_val = -ENOSYS;
 			goto done;
 #endif
 #if defined(CONFIG_ATM_TCP) || defined(CONFIG_ATM_TCP_MODULE)
@@ -1155,40 +1216,6 @@ int atm_getsockopt(struct socket *sock,int level,int optname,
 }
 
 
-/*
- * lane_mpoa_init.c: A couple of helper functions
- * to make modular LANE and MPOA client easier to implement
- */
-
-/*
- * This is how it goes:
- *
- * if xxxx is not compiled as module, call atm_xxxx_init_ops()
- *    from here
- * else call atm_mpoa_init_ops() from init_module() within
- *    the kernel when xxxx module is loaded
- *
- * In either case function pointers in struct atm_xxxx_ops
- * are initialized to their correct values. Either they
- * point to functions in the module or in the kernel
- */
- 
-extern struct atm_mpoa_ops atm_mpoa_ops; /* in common.c */
-extern struct atm_lane_ops atm_lane_ops; /* in common.c */
-
-#if defined(CONFIG_ATM_MPOA) || defined(CONFIG_ATM_MPOA_MODULE)
-void atm_mpoa_init(void)
-{
-#ifndef CONFIG_ATM_MPOA_MODULE /* not module */
-        atm_mpoa_init_ops(&atm_mpoa_ops);
-#else
-	request_module("mpoa");
-#endif
-
-        return;
-}
-#endif
-
 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
 #if defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE)
 struct net_bridge_fdb_entry *(*br_fdb_get_hook)(struct net_bridge *br,
@@ -1199,18 +1226,8 @@ EXPORT_SYMBOL(br_fdb_get_hook);
 EXPORT_SYMBOL(br_fdb_put_hook);
 #endif /* defined(CONFIG_ATM_LANE_MODULE) || defined(CONFIG_BRIDGE_MODULE) */
 #endif /* defined(CONFIG_BRIDGE) || defined(CONFIG_BRIDGE_MODULE) */
+#endif /* defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE) */
 
-void atm_lane_init(void)
-{
-#ifndef CONFIG_ATM_LANE_MODULE /* not module */
-        atm_lane_init_ops(&atm_lane_ops);
-#else
-	request_module("lec");
-#endif
-
-        return;
-}        
-#endif
 
 static int __init atm_init(void)
 {

net/atm/lec.h

@@ -64,7 +64,8 @@ struct atm_lane_ops {
         int (*lecd_attach)(struct atm_vcc *vcc, int arg);
         int (*mcast_attach)(struct atm_vcc *vcc, int arg);
         int (*vcc_attach)(struct atm_vcc *vcc, void *arg);
-        struct net_device **(*get_lecs)(void);
+        struct net_device * (*get_lec)(int itf);
+        struct module *owner;
 };
 
 /*
@@ -102,6 +103,7 @@ struct lec_priv {
            collects all those VCCs. LANEv1 client has only one item in this
            list. These entries are not aged out. */
         atomic_t lec_arp_users;
+        spinlock_t lec_arp_lock;
         struct atm_vcc *mcast_vcc; /* Default Multicast Send VCC */
         struct atm_vcc *lecd;
         struct timer_list lec_arp_timer;
@@ -148,14 +150,16 @@ struct lec_priv {
 int lecd_attach(struct atm_vcc *vcc, int arg);
 int lec_vcc_attach(struct atm_vcc *vcc, void *arg);
 int lec_mcast_attach(struct atm_vcc *vcc, int arg);
-struct net_device **get_dev_lec(void);
+struct net_device *get_dev_lec(int itf);
 int make_lec(struct atm_vcc *vcc);
 int send_to_lecd(struct lec_priv *priv,
                  atmlec_msg_type type, unsigned char *mac_addr,
                  unsigned char *atm_addr, struct sk_buff *data);
 void lec_push(struct atm_vcc *vcc, struct sk_buff *skb);
 
-void atm_lane_init(void);
-void atm_lane_init_ops(struct atm_lane_ops *ops);
+extern struct atm_lane_ops *atm_lane_ops;
+void atm_lane_ops_set(struct atm_lane_ops *hook);
+int try_atm_lane_ops(void);
+
 #endif /* _LEC_H_ */
 

net/atm/mpc.c

@@ -251,12 +251,13 @@ void atm_mpoa_disp_qos(char *page, int *len)
 
 static struct net_device *find_lec_by_itfnum(int itf)
 {
-	extern struct atm_lane_ops atm_lane_ops; /* in common.c */
-	
-	if (atm_lane_ops.get_lecs == NULL)
+	struct net_device *dev;
+	if (!try_atm_lane_ops())
 		return NULL;
 
-	return atm_lane_ops.get_lecs()[itf]; /* FIXME: something better */
+	dev = atm_lane_ops->get_lec(itf);
+	module_put(atm_lane_ops->owner);
+	return dev;
 }
 
 static struct mpoa_client *alloc_mpc(void)
@@ -779,9 +780,10 @@ int atm_mpoa_mpoad_attach (struct atm_vcc *vcc, int arg)
 
 	if (mpc->dev) { /* check if the lec is LANE2 capable */
 		priv = (struct lec_priv *)mpc->dev->priv;
-		if (priv->lane_version < 2)
+		if (priv->lane_version < 2) {
+			dev_put(mpc->dev);
 			mpc->dev = NULL;
-		else
+		} else
 			priv->lane2_ops->associate_indicator = lane2_assoc_ind;  
 	}
 
@@ -802,7 +804,7 @@ int atm_mpoa_mpoad_attach (struct atm_vcc *vcc, int arg)
 			send_set_mps_ctrl_addr(mpc->mps_ctrl_addr, mpc);
 	}
 
-	MOD_INC_USE_COUNT;
+	__module_get(THIS_MODULE);
 	return arg;
 }
 
@@ -839,6 +841,7 @@ static void mpoad_close(struct atm_vcc *vcc)
 		struct lec_priv *priv = (struct lec_priv *)mpc->dev->priv;
 		priv->lane2_ops->associate_indicator = NULL;
 		stop_mpc(mpc);
+		dev_put(mpc->dev);
 	}
 
 	mpc->in_ops->destroy_cache(mpc);
@@ -851,7 +854,7 @@ static void mpoad_close(struct atm_vcc *vcc)
 	
 	printk("mpoa: (%s) going down\n",
 		(mpc->dev) ? mpc->dev->name : "<unknown>");
-	MOD_DEC_USE_COUNT;
+	module_put(THIS_MODULE);
 
 	return;
 }
@@ -975,6 +978,7 @@ static int mpoa_event_listener(struct notifier_block *mpoa_notifier, unsigned lo
 		}
 		mpc->dev_num = priv->itfnum;
 		mpc->dev = dev;
+		dev_hold(dev);
 		dprintk("mpoa: (%s) was initialized\n", dev->name);
 		break;
 	case NETDEV_UNREGISTER:
@@ -984,6 +988,7 @@ static int mpoa_event_listener(struct notifier_block *mpoa_notifier, unsigned lo
 			break;
 		dprintk("mpoa: device (%s) was deallocated\n", dev->name);
 		stop_mpc(mpc);
+		dev_put(mpc->dev);
 		mpc->dev = NULL;
 		break;
 	case NETDEV_UP:
@@ -1393,13 +1398,18 @@ static void mpc_cache_check( unsigned long checking_time  )
 	return;
 }
 
-void atm_mpoa_init_ops(struct atm_mpoa_ops *ops)
+static struct atm_mpoa_ops __atm_mpoa_ops = {
+	.mpoad_attach =	atm_mpoa_mpoad_attach,
+	.vcc_attach =	atm_mpoa_vcc_attach,
+	.owner = THIS_MODULE
+};
+
+static __init int atm_mpoa_init(void)
 {
-	ops->mpoad_attach = atm_mpoa_mpoad_attach;
-	ops->vcc_attach = atm_mpoa_vcc_attach;
+	atm_mpoa_ops_set(&__atm_mpoa_ops);
 
 #ifdef CONFIG_PROC_FS
-	if(mpc_proc_init() != 0)
+	if (mpc_proc_init() != 0)
 		printk(KERN_INFO "mpoa: failed to initialize /proc/mpoa\n");
 	else
 		printk(KERN_INFO "mpoa: /proc/mpoa initialized\n");
@@ -1407,22 +1417,11 @@ void atm_mpoa_init_ops(struct atm_mpoa_ops *ops)
 
 	printk("mpc.c: " __DATE__ " " __TIME__ " initialized\n");
 
-	return;
-}
-
-#ifdef MODULE
-int init_module(void)
-{
-	extern struct atm_mpoa_ops atm_mpoa_ops;
-
-	atm_mpoa_init_ops(&atm_mpoa_ops);
-
 	return 0;
 }
 
-void cleanup_module(void)
+void __exit atm_mpoa_cleanup(void)
 {
-	extern struct atm_mpoa_ops atm_mpoa_ops;
 	struct mpoa_client *mpc, *tmp;
 	struct atm_mpoa_qos *qos, *nextqos;
 	struct lec_priv *priv;
@@ -1433,8 +1432,7 @@ void cleanup_module(void)
 
 	del_timer(&mpc_timer);
 	unregister_netdevice_notifier(&mpoa_notifier);
-	atm_mpoa_ops.mpoad_attach = NULL;
-	atm_mpoa_ops.vcc_attach = NULL;
+	atm_mpoa_ops_set(NULL);
 
 	mpc = mpcs;
 	mpcs = NULL;
@@ -1469,5 +1467,8 @@ void cleanup_module(void)
 
 	return;
 }
-#endif /* MODULE */
+
+module_init(atm_mpoa_init);
+module_exit(atm_mpoa_cleanup);
+
 MODULE_LICENSE("GPL");

net/atm/mpc.h

@@ -48,11 +48,13 @@ struct atm_mpoa_qos {
 struct atm_mpoa_ops {
         int (*mpoad_attach)(struct atm_vcc *vcc, int arg);  /* attach mpoa daemon  */
         int (*vcc_attach)(struct atm_vcc *vcc, long arg);   /* attach shortcut vcc */
+	struct module *owner;
 };
 
 /* Boot/module initialization function */
-void atm_mpoa_init(void);
-void atm_mpoa_init_ops(struct atm_mpoa_ops *ops);
+extern struct atm_mpoa_ops *atm_mpoa_ops;
+int try_atm_mpoa_ops(void);
+void atm_mpoa_ops_set(struct atm_mpoa_ops *hook);
 
 /* MPOA QoS operations */
 struct atm_mpoa_qos *atm_mpoa_add_qos(uint32_t dst_ip, struct atm_qos *qos);

net/atm/proc.c

@@ -47,7 +47,6 @@
 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
 #include "lec.h"
 #include "lec_arpc.h"
-extern struct atm_lane_ops atm_lane_ops; /* in common.c */
 #endif
 
 static ssize_t proc_dev_atm_read(struct file *file,char *buf,size_t count,
@@ -481,57 +480,72 @@ static int atm_arp_info(loff_t pos,char *buf)
 #if defined(CONFIG_ATM_LANE) || defined(CONFIG_ATM_LANE_MODULE)
 static int atm_lec_info(loff_t pos,char *buf)
 {
+	unsigned long flags;
 	struct lec_priv *priv;
 	struct lec_arp_table *entry;
 	int i, count, d, e;
-	struct net_device **dev_lec;
+	struct net_device *dev;
 
 	if (!pos) {
 		return sprintf(buf,"Itf  MAC          ATM destination"
 		    "                          Status            Flags "
 		    "VPI/VCI Recv VPI/VCI\n");
 	}
-	if (atm_lane_ops.get_lecs == NULL)
+	if (!try_atm_lane_ops())
 		return 0; /* the lane module is not there yet */
-	else
-		dev_lec = atm_lane_ops.get_lecs();
 
 	count = pos;
-	for(d=0;d<MAX_LEC_ITF;d++) {
-		if (!dev_lec[d] || !(priv =
-		    (struct lec_priv *) dev_lec[d]->priv)) continue;
-		for(i=0;i<LEC_ARP_TABLE_SIZE;i++) {
-			entry = priv->lec_arp_tables[i];
-			for(;entry;entry=entry->next) {
-				if (--count) continue;
-				e=sprintf(buf,"%s ",
-				    dev_lec[d]->name);
-				lec_info(entry,buf+e);
+	for(d = 0; d < MAX_LEC_ITF; d++) {
+		dev = atm_lane_ops->get_lec(d);
+		if (!dev || !(priv = (struct lec_priv *) dev->priv))
+			continue;
+		spin_lock_irqsave(&priv->lec_arp_lock, flags);
+		for(i = 0; i < LEC_ARP_TABLE_SIZE; i++) {
+			for(entry = priv->lec_arp_tables[i]; entry; entry = entry->next) {
+				if (--count)
+					continue;
+				e = sprintf(buf,"%s ", dev->name);
+				lec_info(entry, buf+e);
+				spin_unlock_irqrestore(&priv->lec_arp_lock, flags);
+				dev_put(dev);
+				module_put(atm_lane_ops->owner);
 				return strlen(buf);
 			}
 		}
-		for(entry=priv->lec_arp_empty_ones; entry;
-		    entry=entry->next) {
-			if (--count) continue;
-			e=sprintf(buf,"%s ",dev_lec[d]->name);
+		for(entry = priv->lec_arp_empty_ones; entry; entry = entry->next) {
+			if (--count)
+				continue;
+			e = sprintf(buf,"%s ", dev->name);
 			lec_info(entry, buf+e);
+			spin_unlock_irqrestore(&priv->lec_arp_lock, flags);
+			dev_put(dev);
+			module_put(atm_lane_ops->owner);
 			return strlen(buf);
 		}
-		for(entry=priv->lec_no_forward; entry;
-		    entry=entry->next) {
-			if (--count) continue;
-			e=sprintf(buf,"%s ",dev_lec[d]->name);
+		for(entry = priv->lec_no_forward; entry; entry=entry->next) {
+			if (--count)
+				continue;
+			e = sprintf(buf,"%s ", dev->name);
 			lec_info(entry, buf+e);
+			spin_unlock_irqrestore(&priv->lec_arp_lock, flags);
+			dev_put(dev);
+			module_put(atm_lane_ops->owner);
 			return strlen(buf);
 		}
-		for(entry=priv->mcast_fwds; entry;
-		    entry=entry->next) {
-			if (--count) continue;
-			e=sprintf(buf,"%s ",dev_lec[d]->name);
+		for(entry = priv->mcast_fwds; entry; entry = entry->next) {
+			if (--count)
+				continue;
+			e = sprintf(buf,"%s ", dev->name);
 			lec_info(entry, buf+e);
+			spin_unlock_irqrestore(&priv->lec_arp_lock, flags);
+			dev_put(dev);
+			module_put(atm_lane_ops->owner);
 			return strlen(buf);
 		}
+		spin_unlock_irqrestore(&priv->lec_arp_lock, flags);
+		dev_put(dev);
 	}
+	module_put(atm_lane_ops->owner);
 	return 0;
 }
 #endif