[PKT_SCHED]: Proper module refcounting for packet classifiers.

include/net/pkt_cls.h

@@ -39,6 +39,8 @@ struct tcf_walker
 	int	(*fn)(struct tcf_proto *, unsigned long node, struct tcf_walker *);
 };
 
+struct module;
+
 struct tcf_proto_ops
 {
 	struct tcf_proto_ops	*next;
@@ -56,6 +58,8 @@ struct tcf_proto_ops
 
 	/* rtnetlink specific */
 	int			(*dump)(struct tcf_proto*, unsigned long, struct sk_buff *skb, struct tcmsg*);
+
+	struct module		*owner;
 };
 
 /* Main classifier routine: scans classifier chain attached

net/sched/cls_api.c

@@ -17,6 +17,7 @@
 #include <asm/system.h>
 #include <asm/bitops.h>
 #include <linux/config.h>
+#include <linux/module.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
@@ -223,8 +224,9 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 		tp->q = q;
 		tp->classify = tp_ops->classify;
 		tp->classid = parent;
-		err = tp_ops->init(tp);
-		if (err) {
+		err = -EBUSY;
+		if (!try_module_get(tp_ops->owner) ||
+		    (err = tp_ops->init(tp)) != 0) {
 			kfree(tp);
 			goto errout;
 		}
@@ -248,6 +250,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n, void *arg)
 			write_unlock(&qdisc_tree_lock);
 
 			tp->ops->destroy(tp);
+			module_put(tp->ops->owner);
 			kfree(tp);
 			err = 0;
 			goto errout;

net/sched/cls_fw.c

@@ -117,7 +117,6 @@ static void fw_put(struct tcf_proto *tp, unsigned long f)
 
 static int fw_init(struct tcf_proto *tp)
 {
-	MOD_INC_USE_COUNT;
 	return 0;
 }
 
@@ -127,10 +126,8 @@ static void fw_destroy(struct tcf_proto *tp)
 	struct fw_filter *f;
 	int h;
 
-	if (head == NULL) {
-		MOD_DEC_USE_COUNT;
+	if (head == NULL)
 		return;
-	}
 
 	for (h=0; h<256; h++) {
 		while ((f=head->ht[h]) != NULL) {
@@ -146,7 +143,6 @@ static void fw_destroy(struct tcf_proto *tp)
 		}
 	}
 	kfree(head);
-	MOD_DEC_USE_COUNT;
 }
 
 static int fw_delete(struct tcf_proto *tp, unsigned long arg)
@@ -351,18 +347,18 @@ static int fw_dump(struct tcf_proto *tp, unsigned long fh,
 }
 
 struct tcf_proto_ops cls_fw_ops = {
-	NULL,
-	"fw",
-	fw_classify,
-	fw_init,
-	fw_destroy,
-
-	fw_get,
-	fw_put,
-	fw_change,
-	fw_delete,
-	fw_walk,
-	fw_dump
+	.next		=	NULL,
+	.kind		=	"fw",
+	.classify	=	fw_classify,
+	.init		=	fw_init,
+	.destroy	=	fw_destroy,
+	.get		=	fw_get,
+	.put		=	fw_put,
+	.change		=	fw_change,
+	.delete		=	fw_delete,
+	.walk		=	fw_walk,
+	.dump		=	fw_dump,
+	.owner		=	THIS_MODULE,
 };
 
 #ifdef MODULE

net/sched/cls_route.c

@@ -272,7 +272,6 @@ static void route4_put(struct tcf_proto *tp, unsigned long f)
 
 static int route4_init(struct tcf_proto *tp)
 {
-	MOD_INC_USE_COUNT;
 	return 0;
 }
 
@@ -281,10 +280,8 @@ static void route4_destroy(struct tcf_proto *tp)
 	struct route4_head *head = xchg(&tp->root, NULL);
 	int h1, h2;
 
-	if (head == NULL) {
-		MOD_DEC_USE_COUNT;
+	if (head == NULL)
 		return;
-	}
 
 	for (h1=0; h1<=256; h1++) {
 		struct route4_bucket *b;
@@ -309,7 +306,6 @@ static void route4_destroy(struct tcf_proto *tp)
 		}
 	}
 	kfree(head);
-	MOD_DEC_USE_COUNT;
 }
 
 static int route4_delete(struct tcf_proto *tp, unsigned long arg)
@@ -607,18 +603,18 @@ static int route4_dump(struct tcf_proto *tp, unsigned long fh,
 }
 
 struct tcf_proto_ops cls_route4_ops = {
-	NULL,
-	"route",
-	route4_classify,
-	route4_init,
-	route4_destroy,
-
-	route4_get,
-	route4_put,
-	route4_change,
-	route4_delete,
-	route4_walk,
-	route4_dump
+	.next		=	NULL,
+	.kind		=	"route",
+	.classify	=	route4_classify,
+	.init		=	route4_init,
+	.destroy	=	route4_destroy,
+	.get		=	route4_get,
+	.put		=	route4_put,
+	.change		=	route4_change,
+	.delete		=	route4_delete,
+	.walk		=	route4_walk,
+	.dump		=	route4_dump,
+	.owner		=	THIS_MODULE,
 };
 
 #ifdef MODULE

net/sched/cls_rsvp.h

@@ -242,14 +242,12 @@ static int rsvp_init(struct tcf_proto *tp)
 {
 	struct rsvp_head *data;
 
-	MOD_INC_USE_COUNT;
 	data = kmalloc(sizeof(struct rsvp_head), GFP_KERNEL);
 	if (data) {
 		memset(data, 0, sizeof(struct rsvp_head));
 		tp->root = data;
 		return 0;
 	}
-	MOD_DEC_USE_COUNT;
 	return -ENOBUFS;
 }
 
@@ -289,7 +287,6 @@ static void rsvp_destroy(struct tcf_proto *tp)
 		}
 	}
 	kfree(data);
-	MOD_DEC_USE_COUNT;
 }
 
 static int rsvp_delete(struct tcf_proto *tp, unsigned long arg)
@@ -668,18 +665,18 @@ static int rsvp_dump(struct tcf_proto *tp, unsigned long fh,
 }
 
 struct tcf_proto_ops RSVP_OPS = {
-	NULL,
-	RSVP_ID,
-	rsvp_classify,
-	rsvp_init,
-	rsvp_destroy,
-
-	rsvp_get,
-	rsvp_put,
-	rsvp_change,
-	rsvp_delete,
-	rsvp_walk,
-	rsvp_dump
+	.next		=	NULL,
+	.kind		=	RSVP_ID,
+	.classify	=	rsvp_classify,
+	.init		=	rsvp_init,
+	.destroy	=	rsvp_destroy,
+	.get		=	rsvp_get,
+	.put		=	rsvp_put,
+	.change		=	rsvp_change,
+	.delete		=	rsvp_delete,
+	.walk		=	rsvp_walk,
+	.dump		=	rsvp_dump,
+	.owner		=	THIS_MODULE,
 };
 
 #ifdef MODULE

net/sched/cls_tcindex.c

@@ -144,12 +144,10 @@ static int tcindex_init(struct tcf_proto *tp)
 	struct tcindex_data *p;
 
 	DPRINTK("tcindex_init(tp %p)\n",tp);
-	MOD_INC_USE_COUNT;
 	p = kmalloc(sizeof(struct tcindex_data),GFP_KERNEL);
-	if (!p) {
-		MOD_DEC_USE_COUNT;
+	if (!p)
 		return -ENOMEM;
-	}
+
 	tp->root = p;
 	p->perfect = NULL;
 	p->h = NULL;
@@ -417,7 +415,6 @@ static void tcindex_destroy(struct tcf_proto *tp)
 		kfree(p->h);
 	kfree(p);
 	tp->root = NULL;
-	MOD_DEC_USE_COUNT;
 }
 
 
@@ -480,18 +477,18 @@ static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
 }
 
 struct tcf_proto_ops cls_tcindex_ops = {
-	NULL,
-	"tcindex",
-	tcindex_classify,
-	tcindex_init,
-	tcindex_destroy,
-
-	tcindex_get,
-	tcindex_put,
-	tcindex_change,
-	tcindex_delete,
-	tcindex_walk,
-	tcindex_dump
+	.next		=	NULL,
+	.kind		=	"tcindex",
+	.classify	=	tcindex_classify,
+	.init		=	tcindex_init,
+	.destroy	=	tcindex_destroy,
+	.get		=	tcindex_get,
+	.put		=	tcindex_put,
+	.change		=	tcindex_change,
+	.delete		=	tcindex_delete,
+	.walk		=	tcindex_walk,
+	.dump		=	tcindex_dump,
+	.owner		=	THIS_MODULE,
 };
 
 

net/sched/cls_u32.c

@@ -257,17 +257,14 @@ static int u32_init(struct tcf_proto *tp)
 	struct tc_u_hnode *root_ht;
 	struct tc_u_common *tp_c;
 
-	MOD_INC_USE_COUNT;
-
 	for (tp_c = u32_list; tp_c; tp_c = tp_c->next)
 		if (tp_c->q == tp->q)
 			break;
 
 	root_ht = kmalloc(sizeof(*root_ht), GFP_KERNEL);
-	if (root_ht == NULL) {
-		MOD_DEC_USE_COUNT;
+	if (root_ht == NULL)
 		return -ENOBUFS;
-	}
+
 	memset(root_ht, 0, sizeof(*root_ht));
 	root_ht->divisor = 0;
 	root_ht->refcnt++;
@@ -277,7 +274,6 @@ static int u32_init(struct tcf_proto *tp)
 		tp_c = kmalloc(sizeof(*tp_c), GFP_KERNEL);
 		if (tp_c == NULL) {
 			kfree(root_ht);
-			MOD_DEC_USE_COUNT;
 			return -ENOBUFS;
 		}
 		memset(tp_c, 0, sizeof(*tp_c));
@@ -402,7 +398,6 @@ static void u32_destroy(struct tcf_proto *tp)
 		kfree(tp_c);
 	}
 
-	MOD_DEC_USE_COUNT;
 	tp->data = NULL;
 }
 
@@ -690,18 +685,18 @@ static int u32_dump(struct tcf_proto *tp, unsigned long fh,
 }
 
 struct tcf_proto_ops cls_u32_ops = {
-	NULL,
-	"u32",
-	u32_classify,
-	u32_init,
-	u32_destroy,
-
-	u32_get,
-	u32_put,
-	u32_change,
-	u32_delete,
-	u32_walk,
-	u32_dump
+	.next		=	NULL,
+	.kind		=	"u32",
+	.classify	=	u32_classify,
+	.init		=	u32_init,
+	.destroy	=	u32_destroy,
+	.get		=	u32_get,
+	.put		=	u32_put,
+	.change		=	u32_change,
+	.delete		=	u32_delete,
+	.walk		=	u32_walk,
+	.dump		=	u32_dump,
+	.owner		=	THIS_MODULE,
 };
 
 #ifdef MODULE