From 8ecd949df59ad0ee752a50f86f9eebb507853922 Mon Sep 17 00:00:00 2001
From: Rostislav Lisovy <lisovy@gmail.com>
Date: Fri, 22 Jun 2012 16:16:39 +0200
Subject: [PATCH] em_canid: Number of rules passed during configuration is no
 longer limited.

---
 net/sched/em_canid.c | 36 +++++++++++++++++++++++-------------
 1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/net/sched/em_canid.c b/net/sched/em_canid.c
index 5cc6e5e4b68..1cdd4a175af 100644
--- a/net/sched/em_canid.c
+++ b/net/sched/em_canid.c
@@ -24,22 +24,22 @@
 #include <net/pkt_cls.h>
 #include <linux/can.h>
 
-#define EM_CAN_RULES_SIZE				32
+#define EM_CAN_RULES_MAX					500
 
 struct canid_match {
-	/*
-	 * Raw rules copied from netlink message; Used for sending
-	 * information to userspace (when 'tc filter show' is invoked)
-	 * AND when matching EFF frames
-	 */
-	struct can_filter rules_raw[EM_CAN_RULES_SIZE];
-
 	/* For each SFF CAN ID (11 bit) there is one record in this bitfield */
 	DECLARE_BITMAP(match_sff, (1 << CAN_SFF_ID_BITS));
 
 	int rules_count;
-	int eff_rules_count;
 	int sff_rules_count;
+	int eff_rules_count;
+
+	/*
+	 * Raw rules copied from netlink message; Used for sending
+	 * information to userspace (when 'tc filter show' is invoked)
+	 * AND when matching EFF frames
+	 */
+	struct can_filter rules_raw[];
 };
 
 /**
@@ -90,7 +90,7 @@ static void em_canid_sff_match_add(struct canid_match *cm, u32 can_id,
 
 static inline struct canid_match *em_canid_priv(struct tcf_ematch *m)
 {
-	return (struct canid_match *) (m)->data;
+	return (struct canid_match *) m->data;
 }
 
 static int em_canid_match(struct sk_buff *skb, struct tcf_ematch *m,
@@ -131,24 +131,29 @@ static int em_canid_change(struct tcf_proto *tp, void *data, int len,
 					 * fixed size EM_CAN_RULES_SIZE
 					 */
 	struct canid_match *cm;
+	struct canid_match *cm_old = (struct canid_match *) m->data;
 	int err;
 	int i;
+	int rulescnt;
 
 	if (len < sizeof(struct can_filter))
 		return -EINVAL;
 
+	rulescnt = len / sizeof(struct can_filter);
+
 	err = -ENOBUFS;
-	cm = kzalloc(sizeof(*cm), GFP_KERNEL);
+	cm = kzalloc(sizeof(struct canid_match) + sizeof(struct can_filter) *
+		rulescnt, GFP_KERNEL);
 	if (cm == NULL)
 		goto errout;
 
 	cm->sff_rules_count = 0;
 	cm->eff_rules_count = 0;
-	cm->rules_count = len/sizeof(struct can_filter);
+	cm->rules_count = rulescnt;
 	err = -EINVAL;
 
 	/* Be sure to fit into the array */
-	if (cm->rules_count > EM_CAN_RULES_SIZE)
+	if (cm->rules_count > EM_CAN_RULES_MAX)
 		goto errout_free;
 
 	/*
@@ -191,6 +196,11 @@ static int em_canid_change(struct tcf_proto *tp, void *data, int len,
 	m->datalen = sizeof(*cm);
 	m->data = (unsigned long) cm;
 
+	if (cm_old != NULL) {
+		printk("canid: Configuring an existing ematch!\n");
+		kfree(cm_old);
+	}
+
 	return 0;
 
 errout_free:
-- 
2.39.2