genl: Hold reference on correct module while netlink-dump.

[ Upstream commit 33c6b1f6 ]

netlink dump operations take module as parameter to hold
reference for entire netlink dump duration.
Currently it holds ref only on genl module which is not correct
when we use ops registered to genl from another module.
Following patch adds module pointer to genl_ops so that netlink
can hold ref count on it.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
CC: Jesse Gross <jesse@nicira.com>
CC: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/net/genetlink.h

@@ -61,6 +61,7 @@ struct genl_family {
 	struct list_head	ops_list;	/* private */
 	struct list_head	family_list;	/* private */
 	struct list_head	mcast_groups;	/* private */
+	struct module		*module;
 };
 
 /**
@@ -121,9 +122,24 @@ struct genl_ops {
 	struct list_head	ops_list;
 };
 
-extern int genl_register_family(struct genl_family *family);
-extern int genl_register_family_with_ops(struct genl_family *family,
+extern int __genl_register_family(struct genl_family *family);
+
+static inline int genl_register_family(struct genl_family *family)
+{
+	family->module = THIS_MODULE;
+	return __genl_register_family(family);
+}
+
+extern int __genl_register_family_with_ops(struct genl_family *family,
 	struct genl_ops *ops, size_t n_ops);
+
+static inline int genl_register_family_with_ops(struct genl_family *family,
+	struct genl_ops *ops, size_t n_ops)
+{
+	family->module = THIS_MODULE;
+	return __genl_register_family_with_ops(family, ops, n_ops);
+}
+
 extern int genl_unregister_family(struct genl_family *family);
 extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
 extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);

net/netlink/genetlink.c

@@ -364,7 +364,7 @@ int genl_unregister_ops(struct genl_family *family, struct genl_ops *ops)
 EXPORT_SYMBOL(genl_unregister_ops);
 
 /**
- * genl_register_family - register a generic netlink family
+ * __genl_register_family - register a generic netlink family
  * @family: generic netlink family
  *
  * Registers the specified family after validating it first. Only one
@@ -374,7 +374,7 @@ EXPORT_SYMBOL(genl_unregister_ops);
  *
  * Return 0 on success or a negative error code.
  */
-int genl_register_family(struct genl_family *family)
+int __genl_register_family(struct genl_family *family)
 {
 	int err = -EINVAL;
 
@@ -430,10 +430,10 @@ int genl_register_family(struct genl_family *family)
 errout:
 	return err;
 }
-EXPORT_SYMBOL(genl_register_family);
+EXPORT_SYMBOL(__genl_register_family);
 
 /**
- * genl_register_family_with_ops - register a generic netlink family
+ * __genl_register_family_with_ops - register a generic netlink family
  * @family: generic netlink family
  * @ops: operations to be registered
  * @n_ops: number of elements to register
@@ -457,12 +457,12 @@ EXPORT_SYMBOL(genl_register_family);
  *
  * Return 0 on success or a negative error code.
  */
-int genl_register_family_with_ops(struct genl_family *family,
+int __genl_register_family_with_ops(struct genl_family *family,
 	struct genl_ops *ops, size_t n_ops)
 {
 	int err, i;
 
-	err = genl_register_family(family);
+	err = __genl_register_family(family);
 	if (err)
 		return err;
 
@@ -476,7 +476,7 @@ int genl_register_family_with_ops(struct genl_family *family,
 	genl_unregister_family(family);
 	return err;
 }
-EXPORT_SYMBOL(genl_register_family_with_ops);
+EXPORT_SYMBOL(__genl_register_family_with_ops);
 
 /**
  * genl_unregister_family - unregister generic netlink family
@@ -603,22 +603,24 @@ static int genl_family_rcv_msg(struct genl_family *family,
 
 		if (!family->parallel_ops) {
 			struct netlink_dump_control c = {
+				.module = family->module,
 				.data = ops,
 				.dump = genl_lock_dumpit,
 				.done = genl_lock_done,
 			};
 
 			genl_unlock();
-			rc = netlink_dump_start(net->genl_sock, skb, nlh, &c);
+			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 			genl_lock();
 
 		} else {
 			struct netlink_dump_control c = {
+				.module = family->module,
 				.dump = ops->dumpit,
 				.done = ops->done,
 			};
 
-			rc = netlink_dump_start(net->genl_sock, skb, nlh, &c);
+			rc = __netlink_dump_start(net->genl_sock, skb, nlh, &c);
 		}
 
 		return rc;