From 71d1656da6cd638110a43e9c873ba97ea3793490 Mon Sep 17 00:00:00 2001
From: Rostislav Lisovy <lisovy@gmail.com>
Date: Thu, 28 Jun 2012 17:47:13 +0200
Subject: [PATCH] em_canid: Removed unnecessary CAN_EFF_MASK masking, error
 handling etc.

---
 net/sched/Kconfig    |  4 ++--
 net/sched/em_canid.c | 48 +++++++++++++++++---------------------------
 2 files changed, 20 insertions(+), 32 deletions(-)

diff --git a/net/sched/Kconfig b/net/sched/Kconfig
index bc0ceab29aa..68a4c38a58b 100644
--- a/net/sched/Kconfig
+++ b/net/sched/Kconfig
@@ -486,11 +486,11 @@ config NET_EMATCH_TEXT
 	  module will be called em_text.
 
 config NET_EMATCH_CANID
-	tristate "CAN ID"
+	tristate "CAN Identifier"
 	depends on NET_EMATCH && CAN
 	---help---
           Say Y here if you want to be able to classify CAN frames based
-          on CAN ID.
+          on CAN Identifier.
 
 	  To compile this code as a module, choose M here: the
 	  module will be called em_canid.
diff --git a/net/sched/em_canid.c b/net/sched/em_canid.c
index 1cdd4a175af..f0c7c757e3a 100644
--- a/net/sched/em_canid.c
+++ b/net/sched/em_canid.c
@@ -24,7 +24,7 @@
 #include <net/pkt_cls.h>
 #include <linux/can.h>
 
-#define EM_CAN_RULES_MAX					500
+#define EM_CAN_RULES_MAX 500
 
 struct canid_match {
 	/* For each SFF CAN ID (11 bit) there is one record in this bitfield */
@@ -98,17 +98,16 @@ static int em_canid_match(struct sk_buff *skb, struct tcf_ematch *m,
 {
 	struct canid_match *cm = em_canid_priv(m);
 	canid_t can_id;
-	unsigned int match = false;
+	int match = false;
 	int i;
+	const struct can_filter *lp;
 
 	can_id = em_canid_get_id(skb);
 
 	if (can_id & CAN_EFF_FLAG) {
-		can_id &= CAN_EFF_MASK;
-
-		for (i = 0; i < cm->eff_rules_count; i++) {
-			if (!(((cm->rules_raw[i].can_id ^ can_id) &
-			    cm->rules_raw[i].can_mask) & CAN_EFF_MASK)) {
+		for (i = 0, lp = cm->rules_raw;
+		     i < cm->eff_rules_count; i++, lp++) {
+			if (!(((lp->can_id ^ can_id) & lp->can_mask))) {
 				match = true;
 				break;
 			}
@@ -132,29 +131,25 @@ static int em_canid_change(struct tcf_proto *tp, void *data, int len,
 					 */
 	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))
+	if (len % sizeof(struct can_filter))
+		return -EINVAL;
+
+	if (len > sizeof(struct can_filter) * EM_CAN_RULES_MAX)
 		return -EINVAL;
 
 	rulescnt = len / sizeof(struct can_filter);
 
-	err = -ENOBUFS;
 	cm = kzalloc(sizeof(struct canid_match) + sizeof(struct can_filter) *
 		rulescnt, GFP_KERNEL);
-	if (cm == NULL)
-		goto errout;
+	if (!cm)
+		return -ENOMEM;
 
 	cm->sff_rules_count = 0;
 	cm->eff_rules_count = 0;
 	cm->rules_count = rulescnt;
-	err = -EINVAL;
-
-	/* Be sure to fit into the array */
-	if (cm->rules_count > EM_CAN_RULES_MAX)
-		goto errout_free;
 
 	/*
 	 * We need two for() loops for copying rules into
@@ -163,8 +158,9 @@ static int em_canid_change(struct tcf_proto *tp, void *data, int len,
 
 	/* Process EFF frame rules*/
 	for (i = 0; i < cm->rules_count; i++) {
-		if ((conf[i].can_id & CAN_EFF_FLAG) &&
-		    (conf[i].can_mask & CAN_EFF_FLAG)) {
+		if (((conf[i].can_id & CAN_EFF_FLAG) &&
+		    (conf[i].can_mask & CAN_EFF_FLAG)) ||
+		    !(conf[i].can_mask & CAN_EFF_FLAG)) {
 			memcpy(cm->rules_raw + cm->eff_rules_count,
 				&conf[i],
 				sizeof(struct can_filter));
@@ -197,16 +193,11 @@ static int em_canid_change(struct tcf_proto *tp, void *data, int len,
 	m->data = (unsigned long) cm;
 
 	if (cm_old != NULL) {
-		printk("canid: Configuring an existing ematch!\n");
+		printk(KERN_ERR"canid: Configuring an existing ematch!\n");
 		kfree(cm_old);
 	}
 
 	return 0;
-
-errout_free:
-	kfree(cm);
-errout:
-	return err;
 }
 
 static void em_canid_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
@@ -224,14 +215,11 @@ static int em_canid_dump(struct sk_buff *skb, struct tcf_ematch *m)
 	 * When configuring this ematch 'rules_count' is set not to exceed
 	 * 'rules_raw' array size
 	 */
-	if (nla_put_nohdr(skb, sizeof(cm->rules_raw[0]) * cm->rules_count,
+	if (nla_put_nohdr(skb, sizeof(struct can_filter) * cm->rules_count,
 	    &cm->rules_raw) < 0)
-		goto nla_put_failure;
+		return -EMSGSIZE;
 
 	return 0;
-
-nla_put_failure:
-	return -1;
 }
 
 static struct tcf_ematch_ops em_canid_ops = {
-- 
2.39.2