1 files changed, 89 insertions, 30 deletions

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index 5abf31e432ca..2a1c00048fd6 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -71,7 +71,7 @@ struct tc_u_hnode {
 	struct tc_u_hnode __rcu	*next;
 	u32			handle;
 	u32			prio;
-	int			refcnt;
+	refcount_t		refcnt;
 	unsigned int		divisor;
 	struct idr		handle_idr;
 	bool			is_root;
@@ -86,12 +86,22 @@ struct tc_u_hnode {
 struct tc_u_common {
 	struct tc_u_hnode __rcu	*hlist;
 	void			*ptr;
-	int			refcnt;
+	refcount_t		refcnt;
 	struct idr		handle_idr;
 	struct hlist_node	hnode;
 	long			knodes;
 };
 
+static u32 handle2id(u32 h)
+{
+	return ((h & 0x80000000) ? ((h >> 20) & 0x7FF) : h);
+}
+
+static u32 id2handle(u32 id)
+{
+	return (id | 0x800U) << 20;
+}
+
 static inline unsigned int u32_hash_fold(__be32 key,
 					 const struct tc_u32_sel *sel,
 					 u8 fshift)
@@ -310,7 +320,7 @@ static u32 gen_new_htid(struct tc_u_common *tp_c, struct tc_u_hnode *ptr)
 	int id = idr_alloc_cyclic(&tp_c->handle_idr, ptr, 1, 0x7FF, GFP_KERNEL);
 	if (id < 0)
 		return 0;
-	return (id | 0x800U) << 20;
+	return id2handle(id);
 }
 
 static struct hlist_head *tc_u_common_hash;
@@ -359,30 +369,32 @@ static int u32_init(struct tcf_proto *tp)
 	if (root_ht == NULL)
 		return -ENOBUFS;
 
-	root_ht->refcnt++;
-	root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : 0x80000000;
+	refcount_set(&root_ht->refcnt, 1);
+	root_ht->handle = tp_c ? gen_new_htid(tp_c, root_ht) : id2handle(0);
 	root_ht->prio = tp->prio;
 	root_ht->is_root = true;
 	idr_init(&root_ht->handle_idr);
 
 	if (tp_c == NULL) {
-		tp_c = kzalloc(struct_size(tp_c, hlist->ht, 1), GFP_KERNEL);
+		tp_c = kzalloc(sizeof(*tp_c), GFP_KERNEL);
 		if (tp_c == NULL) {
 			kfree(root_ht);
 			return -ENOBUFS;
 		}
+		refcount_set(&tp_c->refcnt, 1);
 		tp_c->ptr = key;
 		INIT_HLIST_NODE(&tp_c->hnode);
 		idr_init(&tp_c->handle_idr);
 
 		hlist_add_head(&tp_c->hnode, tc_u_hash(key));
+	} else {
+		refcount_inc(&tp_c->refcnt);
 	}
 
-	tp_c->refcnt++;
 	RCU_INIT_POINTER(root_ht->next, tp_c->hlist);
 	rcu_assign_pointer(tp_c->hlist, root_ht);
 
-	root_ht->refcnt++;
+	/* root_ht must be destroyed when tcf_proto is destroyed */
 	rcu_assign_pointer(tp->root, root_ht);
 	tp->data = tp_c;
 	return 0;
@@ -393,7 +405,7 @@ static void __u32_destroy_key(struct tc_u_knode *n)
 	struct tc_u_hnode *ht = rtnl_dereference(n->ht_down);
 
 	tcf_exts_destroy(&n->exts);
-	if (ht && --ht->refcnt == 0)
+	if (ht && refcount_dec_and_test(&ht->refcnt))
 		kfree(ht);
 	kfree(n);
 }
@@ -601,8 +613,6 @@ static int u32_destroy_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht,
 	struct tc_u_hnode __rcu **hn;
 	struct tc_u_hnode *phn;
 
-	WARN_ON(--ht->refcnt);
-
 	u32_clear_hnode(tp, ht, extack);
 
 	hn = &tp_c->hlist;
@@ -612,7 +622,7 @@ static int u32_destroy_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht,
 		if (phn == ht) {
 			u32_clear_hw_hnode(tp, ht, extack);
 			idr_destroy(&ht->handle_idr);
-			idr_remove(&tp_c->handle_idr, ht->handle);
+			idr_remove(&tp_c->handle_idr, handle2id(ht->handle));
 			RCU_INIT_POINTER(*hn, ht->next);
 			kfree_rcu(ht, rcu);
 			return 0;
@@ -630,10 +640,10 @@ static void u32_destroy(struct tcf_proto *tp, bool rtnl_held,
 
 	WARN_ON(root_ht == NULL);
 
-	if (root_ht && --root_ht->refcnt == 1)
+	if (root_ht && refcount_dec_and_test(&root_ht->refcnt))
 		u32_destroy_hnode(tp, root_ht, extack);
 
-	if (--tp_c->refcnt == 0) {
+	if (refcount_dec_and_test(&tp_c->refcnt)) {
 		struct tc_u_hnode *ht;
 
 		hlist_del(&tp_c->hnode);
@@ -645,7 +655,7 @@ static void u32_destroy(struct tcf_proto *tp, bool rtnl_held,
 			/* u32_destroy_key() will later free ht for us, if it's
 			 * still referenced by some knode
 			 */
-			if (--ht->refcnt == 0)
+			if (refcount_dec_and_test(&ht->refcnt))
 				kfree_rcu(ht, rcu);
 		}
 
@@ -674,7 +684,7 @@ static int u32_delete(struct tcf_proto *tp, void *arg, bool *last,
 		return -EINVAL;
 	}
 
-	if (ht->refcnt == 1) {
+	if (refcount_dec_if_one(&ht->refcnt)) {
 		u32_destroy_hnode(tp, ht, extack);
 	} else {
 		NL_SET_ERR_MSG_MOD(extack, "Can not delete in-use filter");
@@ -682,7 +692,7 @@ static int u32_delete(struct tcf_proto *tp, void *arg, bool *last,
 	}
 
 out:
-	*last = tp_c->refcnt == 1 && tp_c->knodes == 0;
+	*last = refcount_read(&tp_c->refcnt) == 1 && tp_c->knodes == 0;
 	return ret;
 }
 
@@ -766,14 +776,14 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
 				NL_SET_ERR_MSG_MOD(extack, "Not linking to root node");
 				return -EINVAL;
 			}
-			ht_down->refcnt++;
+			refcount_inc(&ht_down->refcnt);
 		}
 
 		ht_old = rtnl_dereference(n->ht_down);
 		rcu_assign_pointer(n->ht_down, ht_down);
 
 		if (ht_old)
-			ht_old->refcnt--;
+			refcount_dec(&ht_old->refcnt);
 	}
 
 	if (ifindex >= 0)
@@ -826,7 +836,6 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp,
 
 	new->ifindex = n->ifindex;
 	new->fshift = n->fshift;
-	new->res = n->res;
 	new->flags = n->flags;
 	RCU_INIT_POINTER(new->ht_down, ht);
 
@@ -853,7 +862,7 @@ static struct tc_u_knode *u32_init_knode(struct net *net, struct tcf_proto *tp,
 
 	/* bump reference count as long as we hold pointer to structure */
 	if (ht)
-		ht->refcnt++;
+		refcount_inc(&ht->refcnt);
 
 	return new;
 }
@@ -933,7 +942,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 
 				ht_old = rtnl_dereference(n->ht_down);
 				if (ht_old)
-					ht_old->refcnt++;
+					refcount_inc(&ht_old->refcnt);
 			}
 			__u32_destroy_key(new);
 			return err;
@@ -942,6 +951,8 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		if (!tc_in_hw(new->flags))
 			new->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 
+		tcf_proto_update_usesw(tp, new->flags);
+
 		u32_replace_knode(tp, tp_c, new);
 		tcf_unbind_filter(tp, &n->res);
 		tcf_exts_get_net(&n->exts);
@@ -981,7 +992,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 				return err;
 			}
 		}
-		ht->refcnt = 1;
+		refcount_set(&ht->refcnt, 1);
 		ht->divisor = divisor;
 		ht->handle = handle;
 		ht->prio = tp->prio;
@@ -990,7 +1001,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 
 		err = u32_replace_hw_hnode(tp, ht, userflags, extack);
 		if (err) {
-			idr_remove(&tp_c->handle_idr, handle);
+			idr_remove(&tp_c->handle_idr, handle2id(handle));
 			kfree(ht);
 			return err;
 		}
@@ -1024,18 +1035,62 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		return -EINVAL;
 	}
 
+	/* At this point, we need to derive the new handle that will be used to
+	 * uniquely map the identity of this table match entry. The
+	 * identity of the entry that we need to construct is 32 bits made of:
+	 *     htid(12b):bucketid(8b):node/entryid(12b)
+	 *
+	 * At this point _we have the table(ht)_ in which we will insert this
+	 * entry. We carry the table's id in variable "htid".
+	 * Note that earlier code picked the ht selection either by a) the user
+	 * providing the htid specified via TCA_U32_HASH attribute or b) when
+	 * no such attribute is passed then the root ht, is default to at ID
+	 * 0x[800][00][000]. Rule: the root table has a single bucket with ID 0.
+	 * If OTOH the user passed us the htid, they may also pass a bucketid of
+	 * choice. 0 is fine. For example a user htid is 0x[600][01][000] it is
+	 * indicating hash bucketid of 1. Rule: the entry/node ID _cannot_ be
+	 * passed via the htid, so even if it was non-zero it will be ignored.
+	 *
+	 * We may also have a handle, if the user passed one. The handle also
+	 * carries the same addressing of htid(12b):bucketid(8b):node/entryid(12b).
+	 * Rule: the bucketid on the handle is ignored even if one was passed;
+	 * rather the value on "htid" is always assumed to be the bucketid.
+	 */
 	if (handle) {
+		/* Rule: The htid from handle and tableid from htid must match */
 		if (TC_U32_HTID(handle) && TC_U32_HTID(handle ^ htid)) {
 			NL_SET_ERR_MSG_MOD(extack, "Handle specified hash table address mismatch");
 			return -EINVAL;
 		}
-		handle = htid | TC_U32_NODE(handle);
-		err = idr_alloc_u32(&ht->handle_idr, NULL, &handle, handle,
-				    GFP_KERNEL);
-		if (err)
-			return err;
-	} else
+		/* Ok, so far we have a valid htid(12b):bucketid(8b) but we
+		 * need to finalize the table entry identification with the last
+		 * part - the node/entryid(12b)). Rule: Nodeid _cannot be 0_ for
+		 * entries. Rule: nodeid of 0 is reserved only for tables(see
+		 * earlier code which processes TC_U32_DIVISOR attribute).
+		 * Rule: The nodeid can only be derived from the handle (and not
+		 * htid).
+		 * Rule: if the handle specified zero for the node id example
+		 * 0x60000000, then pick a new nodeid from the pool of IDs
+		 * this hash table has been allocating from.
+		 * If OTOH it is specified (i.e for example the user passed a
+		 * handle such as 0x60000123), then we use it generate our final
+		 * handle which is used to uniquely identify the match entry.
+		 */
+		if (!TC_U32_NODE(handle)) {
+			handle = gen_new_kid(ht, htid);
+		} else {
+			handle = htid | TC_U32_NODE(handle);
+			err = idr_alloc_u32(&ht->handle_idr, NULL, &handle,
+					    handle, GFP_KERNEL);
+			if (err)
+				return err;
+		}
+	} else {
+		/* The user did not give us a handle; lets just generate one
+		 * from the table's pool of nodeids.
+		 */
 		handle = gen_new_kid(ht, htid);
+	}
 
 	if (tb[TCA_U32_SEL] == NULL) {
 		NL_SET_ERR_MSG_MOD(extack, "Selector not specified");
@@ -1111,6 +1166,8 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
 		if (!tc_in_hw(n->flags))
 			n->flags |= TCA_CLS_FLAGS_NOT_IN_HW;
 
+		tcf_proto_update_usesw(tp, n->flags);
+
 		ins = &ht->ht[TC_U32_HASH(handle)];
 		for (pins = rtnl_dereference(*ins); pins;
 		     ins = &pins->next, pins = rtnl_dereference(*ins))
@@ -1410,6 +1467,7 @@ static struct tcf_proto_ops cls_u32_ops __read_mostly = {
 	.bind_class	=	u32_bind_class,
 	.owner		=	THIS_MODULE,
 };
+MODULE_ALIAS_NET_CLS("u32");
 
 static int __init init_u32(void)
 {
@@ -1446,4 +1504,5 @@ static void __exit exit_u32(void)
 
 module_init(init_u32)
 module_exit(exit_u32)
+MODULE_DESCRIPTION("Universal 32bit based TC Classifier");
 MODULE_LICENSE("GPL");