diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 1b3fe38..f931b76 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -195,8 +195,8 @@ struct qeth_vnicc_info {
 #define QETH_IN_BUF_SIZE_DEFAULT 65536
 #define QETH_IN_BUF_COUNT_DEFAULT 64
 #define QETH_IN_BUF_COUNT_HSDEFAULT 128
-#define QETH_IN_BUF_COUNT_MIN 8
-#define QETH_IN_BUF_COUNT_MAX 128
+#define QETH_IN_BUF_COUNT_MIN	8U
+#define QETH_IN_BUF_COUNT_MAX	128U
 #define QETH_MAX_BUFFER_ELEMENTS(card) ((card)->qdio.in_buf_size >> 12)
 #define QETH_IN_BUF_REQUEUE_THRESHOLD(card) \
 		 ((card)->qdio.in_buf_pool.buf_count / 2)
diff --git a/drivers/s390/net/qeth_core_sys.c b/drivers/s390/net/qeth_core_sys.c
index 8def823..74c70364 100644
--- a/drivers/s390/net/qeth_core_sys.c
+++ b/drivers/s390/net/qeth_core_sys.c
@@ -103,21 +103,21 @@ static ssize_t qeth_dev_portno_store(struct device *dev,
 		struct device_attribute *attr, const char *buf, size_t count)
 {
 	struct qeth_card *card = dev_get_drvdata(dev);
-	char *tmp;
 	unsigned int portno, limit;
 	int rc = 0;
 
+	rc = kstrtouint(buf, 16, &portno);
+	if (rc)
+		return rc;
+	if (portno > QETH_MAX_PORTNO)
+		return -EINVAL;
+
 	mutex_lock(&card->conf_mutex);
 	if (card->state != CARD_STATE_DOWN) {
 		rc = -EPERM;
 		goto out;
 	}
 
-	portno = simple_strtoul(buf, &tmp, 16);
-	if (portno > QETH_MAX_PORTNO) {
-		rc = -EINVAL;
-		goto out;
-	}
 	limit = (card->ssqd.pcnt ? card->ssqd.pcnt - 1 : card->ssqd.pcnt);
 	if (portno > limit) {
 		rc = -EINVAL;
@@ -248,19 +248,19 @@ static ssize_t qeth_dev_bufcnt_store(struct device *dev,
 {
 	struct qeth_card *card = dev_get_drvdata(dev);
 	unsigned int cnt;
-	char *tmp;
 	int rc = 0;
 
+	rc = kstrtouint(buf, 10, &cnt);
+	if (rc)
+		return rc;
+
 	mutex_lock(&card->conf_mutex);
 	if (card->state != CARD_STATE_DOWN) {
 		rc = -EPERM;
 		goto out;
 	}
 
-	cnt = simple_strtoul(buf, &tmp, 10);
-	cnt = (cnt < QETH_IN_BUF_COUNT_MIN) ? QETH_IN_BUF_COUNT_MIN :
-		((cnt > QETH_IN_BUF_COUNT_MAX) ? QETH_IN_BUF_COUNT_MAX : cnt);
-
+	cnt = clamp(cnt, QETH_IN_BUF_COUNT_MIN, QETH_IN_BUF_COUNT_MAX);
 	rc = qeth_resize_buffer_pool(card, cnt);
 
 out:
@@ -341,18 +341,15 @@ static ssize_t qeth_dev_layer2_store(struct device *dev,
 {
 	struct qeth_card *card = dev_get_drvdata(dev);
 	struct net_device *ndev;
-	char *tmp;
-	int i, rc = 0;
 	enum qeth_discipline_id newdis;
+	unsigned int input;
+	int rc;
 
-	mutex_lock(&card->discipline_mutex);
-	if (card->state != CARD_STATE_DOWN) {
-		rc = -EPERM;
-		goto out;
-	}
+	rc = kstrtouint(buf, 16, &input);
+	if (rc)
+		return rc;
 
-	i = simple_strtoul(buf, &tmp, 16);
-	switch (i) {
+	switch (input) {
 	case 0:
 		newdis = QETH_DISCIPLINE_LAYER3;
 		break;
@@ -360,7 +357,12 @@ static ssize_t qeth_dev_layer2_store(struct device *dev,
 		newdis = QETH_DISCIPLINE_LAYER2;
 		break;
 	default:
-		rc = -EINVAL;
+		return -EINVAL;
+	}
+
+	mutex_lock(&card->discipline_mutex);
+	if (card->state != CARD_STATE_DOWN) {
+		rc = -EPERM;
 		goto out;
 	}
 
@@ -551,20 +553,21 @@ static DEVICE_ATTR(hw_trap, 0644, qeth_hw_trap_show,
 static ssize_t qeth_dev_blkt_store(struct qeth_card *card,
 		const char *buf, size_t count, int *value, int max_value)
 {
-	char *tmp;
-	int i, rc = 0;
+	unsigned int input;
+	int rc;
+
+	rc = kstrtouint(buf, 10, &input);
+	if (rc)
+		return rc;
+
+	if (input > max_value)
+		return -EINVAL;
 
 	mutex_lock(&card->conf_mutex);
-	if (card->state != CARD_STATE_DOWN) {
+	if (card->state != CARD_STATE_DOWN)
 		rc = -EPERM;
-		goto out;
-	}
-	i = simple_strtoul(buf, &tmp, 10);
-	if (i <= max_value)
-		*value = i;
 	else
-		rc = -EINVAL;
-out:
+		*value = input;
 	mutex_unlock(&card->conf_mutex);
 	return rc ? rc : count;
 }
diff --git a/drivers/s390/net/qeth_l3.h b/drivers/s390/net/qeth_l3.h
index 6ccfe21..acd130cf 100644
--- a/drivers/s390/net/qeth_l3.h
+++ b/drivers/s390/net/qeth_l3.h
@@ -96,7 +96,7 @@ struct qeth_ipato_entry {
 	struct list_head entry;
 	enum qeth_prot_versions proto;
 	char addr[16];
-	int mask_bits;
+	unsigned int mask_bits;
 };
 
 extern const struct attribute_group *qeth_l3_attr_groups[];
@@ -110,7 +110,7 @@ int qeth_l3_setrouting_v6(struct qeth_card *);
 int qeth_l3_add_ipato_entry(struct qeth_card *, struct qeth_ipato_entry *);
 int qeth_l3_del_ipato_entry(struct qeth_card *card,
 			    enum qeth_prot_versions proto, u8 *addr,
-			    int mask_bits);
+			    unsigned int mask_bits);
 void qeth_l3_update_ipato(struct qeth_card *card);
 int qeth_l3_modify_hsuid(struct qeth_card *card, bool add);
 int qeth_l3_modify_rxip_vipa(struct qeth_card *card, bool add, const u8 *ip,
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 810d65f..876a21d 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -105,11 +105,9 @@ static bool qeth_l3_is_addr_covered_by_ipato(struct qeth_card *card,
 					  (ipatoe->proto == QETH_PROT_IPV4) ?
 					  4 : 16);
 		if (addr->proto == QETH_PROT_IPV4)
-			rc = !memcmp(addr_bits, ipatoe_bits,
-				     min(32, ipatoe->mask_bits));
+			rc = !memcmp(addr_bits, ipatoe_bits, ipatoe->mask_bits);
 		else
-			rc = !memcmp(addr_bits, ipatoe_bits,
-				     min(128, ipatoe->mask_bits));
+			rc = !memcmp(addr_bits, ipatoe_bits, ipatoe->mask_bits);
 		if (rc)
 			break;
 	}
@@ -561,7 +559,7 @@ int qeth_l3_add_ipato_entry(struct qeth_card *card,
 
 int qeth_l3_del_ipato_entry(struct qeth_card *card,
 			    enum qeth_prot_versions proto, u8 *addr,
-			    int mask_bits)
+			    unsigned int mask_bits)
 {
 	struct qeth_ipato_entry *ipatoe, *tmp;
 	int rc = -ENOENT;
diff --git a/drivers/s390/net/qeth_l3_sys.c b/drivers/s390/net/qeth_l3_sys.c
index 05fa986..351763a 100644
--- a/drivers/s390/net/qeth_l3_sys.c
+++ b/drivers/s390/net/qeth_l3_sys.c
@@ -407,10 +407,9 @@ static ssize_t qeth_l3_dev_ipato_add4_show(struct device *dev,
 }
 
 static int qeth_l3_parse_ipatoe(const char *buf, enum qeth_prot_versions proto,
-		  u8 *addr, int *mask_bits)
+				u8 *addr, unsigned int *mask_bits)
 {
-	const char *start;
-	char *sep, *tmp;
+	char *sep;
 	int rc;
 
 	/* Expected input pattern: %addr/%mask */
@@ -424,13 +423,13 @@ static int qeth_l3_parse_ipatoe(const char *buf, enum qeth_prot_versions proto,
 	if (rc)
 		return rc;
 
-	start = sep + 1;
-	*mask_bits = simple_strtoul(start, &tmp, 10);
-	if (!strlen(start) ||
-	    (tmp == start) ||
-	    (*mask_bits > ((proto == QETH_PROT_IPV4) ? 32 : 128))) {
+	rc = kstrtouint(sep + 1, 10, mask_bits);
+	if (rc)
+		return rc;
+
+	if (*mask_bits > ((proto == QETH_PROT_IPV4) ? 32 : 128))
 		return -EINVAL;
-	}
+
 	return 0;
 }
 
@@ -438,8 +437,8 @@ static ssize_t qeth_l3_dev_ipato_add_store(const char *buf, size_t count,
 			 struct qeth_card *card, enum qeth_prot_versions proto)
 {
 	struct qeth_ipato_entry *ipatoe;
+	unsigned int mask_bits;
 	u8 addr[16];
-	int mask_bits;
 	int rc = 0;
 
 	rc = qeth_l3_parse_ipatoe(buf, proto, addr, &mask_bits);
@@ -476,8 +475,8 @@ static QETH_DEVICE_ATTR(ipato_add4, add4, 0644,
 static ssize_t qeth_l3_dev_ipato_del_store(const char *buf, size_t count,
 			 struct qeth_card *card, enum qeth_prot_versions proto)
 {
+	unsigned int mask_bits;
 	u8 addr[16];
-	int mask_bits;
 	int rc = 0;
 
 	rc = qeth_l3_parse_ipatoe(buf, proto, addr, &mask_bits);