Merge branch 's390-qeth-next'

Julian Wiedmann says:

====================
s390/net: more updates for 4.14

please apply another batch of qeth patches for net-next.
This reworks the xmit path for L2 OSAs to use skb_cow_head() instead of
skb_realloc_headroom().
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_core.h

@@ -949,9 +949,10 @@ int qeth_get_elements_for_frags(struct sk_buff *);
 int qeth_do_send_packet_fast(struct qeth_card *card,
 			     struct qeth_qdio_out_q *queue, struct sk_buff *skb,
 			     struct qeth_hdr *hdr, unsigned int offset,
-			     int hd_len);
-int qeth_do_send_packet(struct qeth_card *, struct qeth_qdio_out_q *,
-		    struct sk_buff *, struct qeth_hdr *, int);
+			     unsigned int hd_len);
+int qeth_do_send_packet(struct qeth_card *card, struct qeth_qdio_out_q *queue,
+			struct sk_buff *skb, struct qeth_hdr *hdr,
+			unsigned int hd_len, unsigned int offset, int elements);
 int qeth_do_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
 int qeth_core_get_sset_count(struct net_device *, int);
 void qeth_core_get_ethtool_stats(struct net_device *,
@@ -984,6 +985,7 @@ int qeth_set_features(struct net_device *, netdev_features_t);
 int qeth_recover_features(struct net_device *);
 netdev_features_t qeth_fix_features(struct net_device *, netdev_features_t);
 int qeth_vm_request_mac(struct qeth_card *card);
+int qeth_push_hdr(struct sk_buff *skb, struct qeth_hdr **hdr, unsigned int len);
 
 /* exports for OSN */
 int qeth_osn_assist(struct net_device *, void *, int);

drivers/s390/net/qeth_core_main.c

@@ -3890,6 +3890,34 @@ int qeth_hdr_chk_and_bounce(struct sk_buff *skb, struct qeth_hdr **hdr, int len)
 }
 EXPORT_SYMBOL_GPL(qeth_hdr_chk_and_bounce);
 
+/**
+ * qeth_push_hdr() - push a qeth_hdr onto an skb.
+ * @skb: skb that the qeth_hdr should be pushed onto.
+ * @hdr: double pointer to a qeth_hdr. When returning with >= 0,
+ *	 it contains a valid pointer to a qeth_hdr.
+ * @len: length of the hdr that needs to be pushed on.
+ *
+ * Returns the pushed length. If the header can't be pushed on
+ * (eg. because it would cross a page boundary), it is allocated from
+ * the cache instead and 0 is returned.
+ * Error to create the hdr is indicated by returning with < 0.
+ */
+int qeth_push_hdr(struct sk_buff *skb, struct qeth_hdr **hdr, unsigned int len)
+{
+	if (skb_headroom(skb) >= len &&
+	    qeth_get_elements_for_range((addr_t)skb->data - len,
+					(addr_t)skb->data) == 1) {
+		*hdr = skb_push(skb, len);
+		return len;
+	}
+	/* fall back */
+	*hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC);
+	if (!*hdr)
+		return -ENOMEM;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qeth_push_hdr);
+
 static void __qeth_fill_buffer(struct sk_buff *skb,
 			       struct qeth_qdio_out_buffer *buf,
 			       bool is_first_elem, unsigned int offset)
@@ -3953,43 +3981,38 @@ static void __qeth_fill_buffer(struct sk_buff *skb,
 	buf->next_element_to_fill = element;
 }
 
+/**
+ * qeth_fill_buffer() - map skb into an output buffer
+ * @queue:	QDIO queue to submit the buffer on
+ * @buf:	buffer to transport the skb
+ * @skb:	skb to map into the buffer
+ * @hdr:	qeth_hdr for this skb. Either at skb->data, or allocated
+ *		from qeth_core_header_cache.
+ * @offset:	when mapping the skb, start at skb->data + offset
+ * @hd_len:	if > 0, build a dedicated header element of this size
+ */
 static int qeth_fill_buffer(struct qeth_qdio_out_q *queue,
 			    struct qeth_qdio_out_buffer *buf,
 			    struct sk_buff *skb, struct qeth_hdr *hdr,
-			    unsigned int offset, int hd_len)
+			    unsigned int offset, unsigned int hd_len)
 {
-	struct qdio_buffer *buffer;
-	int flush_cnt = 0, hdr_len;
+	struct qdio_buffer *buffer = buf->buffer;
 	bool is_first_elem = true;
+	int flush_cnt = 0;
 
-	buffer = buf->buffer;
 	refcount_inc(&skb->users);
 	skb_queue_tail(&buf->skb_list, skb);
 
-	if (hdr->hdr.l3.id == QETH_HEADER_TYPE_TSO) {
-		int element = buf->next_element_to_fill;
-		is_first_elem = false;
-
-		hdr_len = sizeof(struct qeth_hdr_tso) +
-			((struct qeth_hdr_tso *)hdr)->ext.dg_hdr_len;
-		/*fill first buffer entry only with header information */
-		buffer->element[element].addr = skb->data;
-		buffer->element[element].length = hdr_len;
-		buffer->element[element].eflags = SBAL_EFLAGS_FIRST_FRAG;
-		buf->next_element_to_fill++;
-		skb_pull(skb, hdr_len);
-	}
-
-	/* IQD */
-	if (offset > 0) {
+	/* build dedicated header element */
+	if (hd_len) {
 		int element = buf->next_element_to_fill;
 		is_first_elem = false;
 
 		buffer->element[element].addr = hdr;
-		buffer->element[element].length = sizeof(struct qeth_hdr) +
-							hd_len;
+		buffer->element[element].length = hd_len;
 		buffer->element[element].eflags = SBAL_EFLAGS_FIRST_FRAG;
-		buf->is_header[element] = 1;
+		/* remember to free cache-allocated qeth_hdr: */
+		buf->is_header[element] = ((void *)hdr != skb->data);
 		buf->next_element_to_fill++;
 	}
 
@@ -4020,7 +4043,7 @@ static int qeth_fill_buffer(struct qeth_qdio_out_q *queue,
 int qeth_do_send_packet_fast(struct qeth_card *card,
 			     struct qeth_qdio_out_q *queue, struct sk_buff *skb,
 			     struct qeth_hdr *hdr, unsigned int offset,
-			     int hd_len)
+			     unsigned int hd_len)
 {
 	struct qeth_qdio_out_buffer *buffer;
 	int index;
@@ -4050,8 +4073,9 @@ int qeth_do_send_packet_fast(struct qeth_card *card,
 EXPORT_SYMBOL_GPL(qeth_do_send_packet_fast);
 
 int qeth_do_send_packet(struct qeth_card *card, struct qeth_qdio_out_q *queue,
-		struct sk_buff *skb, struct qeth_hdr *hdr,
-		int elements_needed)
+			struct sk_buff *skb, struct qeth_hdr *hdr,
+			unsigned int offset, unsigned int hd_len,
+			int elements_needed)
 {
 	struct qeth_qdio_out_buffer *buffer;
 	int start_index;
@@ -4100,7 +4124,7 @@ int qeth_do_send_packet(struct qeth_card *card, struct qeth_qdio_out_q *queue,
 			}
 		}
 	}
-	tmp = qeth_fill_buffer(queue, buffer, skb, hdr, 0, 0);
+	tmp = qeth_fill_buffer(queue, buffer, skb, hdr, offset, hd_len);
 	queue->next_buf_to_fill = (queue->next_buf_to_fill + tmp) %
 				  QDIO_MAX_BUFFERS_PER_Q;
 	flush_count += tmp;

drivers/s390/net/qeth_l2_main.c

@@ -259,13 +259,14 @@ static void qeth_l2_hdr_csum(struct qeth_card *card, struct qeth_hdr *hdr,
 		card->perf_stats.tx_csum++;
 }
 
-static void qeth_l2_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
-			struct sk_buff *skb, int cast_type)
+static void qeth_l2_fill_header(struct qeth_hdr *hdr, struct sk_buff *skb,
+				int cast_type, unsigned int data_len)
 {
 	struct vlan_ethhdr *veth = (struct vlan_ethhdr *)skb_mac_header(skb);
 
 	memset(hdr, 0, sizeof(struct qeth_hdr));
 	hdr->hdr.l2.id = QETH_HEADER_TYPE_LAYER2;
+	hdr->hdr.l2.pkt_length = data_len;
 
 	/* set byte byte 3 to casting flags */
 	if (cast_type == RTN_MULTICAST)
@@ -275,7 +276,6 @@ static void qeth_l2_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
 	else
 		hdr->hdr.l2.flags[2] |= QETH_LAYER2_FLAG_UNICAST;
 
-	hdr->hdr.l2.pkt_length = skb->len - sizeof(struct qeth_hdr);
 	/* VSWITCH relies on the VLAN
 	 * information to be present in
 	 * the QDIO header */
@@ -676,143 +676,172 @@ static void qeth_l2_set_rx_mode(struct net_device *dev)
 		qeth_promisc_to_bridge(card);
 }
 
-static netdev_tx_t qeth_l2_hard_start_xmit(struct sk_buff *skb,
-					   struct net_device *dev)
+static int qeth_l2_xmit_iqd(struct qeth_card *card, struct sk_buff *skb,
+			    struct qeth_qdio_out_q *queue, int cast_type)
 {
+	unsigned int data_offset = ETH_HLEN;
+	struct qeth_hdr *hdr;
 	int rc;
-	struct qeth_hdr *hdr = NULL;
-	int elements = 0;
-	struct qeth_card *card = dev->ml_priv;
-	struct sk_buff *new_skb = skb;
-	int cast_type = qeth_l2_get_cast_type(card, skb);
-	struct qeth_qdio_out_q *queue;
-	int tx_bytes = skb->len;
-	int data_offset = -1;
-	int elements_needed = 0;
-	int hd_len = 0;
-	unsigned int nr_frags;
 
-	if (card->qdio.do_prio_queueing || (cast_type &&
-					card->info.is_multicast_different))
-		queue = card->qdio.out_qs[qeth_get_priority_queue(card, skb,
-					qeth_get_ip_version(skb), cast_type)];
-	else
-		queue = card->qdio.out_qs[card->qdio.default_out_queue];
+	hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC);
+	if (!hdr)
+		return -ENOMEM;
+	qeth_l2_fill_header(hdr, skb, cast_type, skb->len);
+	skb_copy_from_linear_data(skb, ((char *)hdr) + sizeof(*hdr),
+				  data_offset);
 
-	if ((card->state != CARD_STATE_UP) || !card->lan_online) {
-		card->stats.tx_carrier_errors++;
-		goto tx_drop;
+	if (!qeth_get_elements_no(card, skb, 1, data_offset)) {
+		rc = -E2BIG;
+		goto out;
 	}
+	rc = qeth_do_send_packet_fast(card, queue, skb, hdr, data_offset,
+				      sizeof(*hdr) + data_offset);
+out:
+	if (rc)
+		kmem_cache_free(qeth_core_header_cache, hdr);
+	return rc;
+}
 
-	if ((card->info.type == QETH_CARD_TYPE_OSN) &&
-	    (skb->protocol == htons(ETH_P_IPV6)))
-		goto tx_drop;
-
-	if (card->options.performance_stats) {
-		card->perf_stats.outbound_cnt++;
-		card->perf_stats.outbound_start_time = qeth_get_micros();
-	}
-	netif_stop_queue(dev);
+static int qeth_l2_xmit_osa(struct qeth_card *card, struct sk_buff *skb,
+			    struct qeth_qdio_out_q *queue, int cast_type)
+{
+	int push_len = sizeof(struct qeth_hdr);
+	unsigned int elements, nr_frags;
+	unsigned int hdr_elements = 0;
+	struct qeth_hdr *hdr = NULL;
+	unsigned int hd_len = 0;
+	int rc;
 
 	/* fix hardware limitation: as long as we do not have sbal
 	 * chaining we can not send long frag lists
 	 */
-	if ((card->info.type != QETH_CARD_TYPE_IQD) &&
-	    !qeth_get_elements_no(card, new_skb, 0, 0)) {
-		int lin_rc = skb_linearize(new_skb);
+	if (!qeth_get_elements_no(card, skb, 0, 0)) {
+		rc = skb_linearize(skb);
 
 		if (card->options.performance_stats) {
-			if (lin_rc)
+			if (rc)
 				card->perf_stats.tx_linfail++;
 			else
 				card->perf_stats.tx_lin++;
 		}
-		if (lin_rc)
-			goto tx_drop;
-	}
-	nr_frags = skb_shinfo(new_skb)->nr_frags;
-
-	if (card->info.type == QETH_CARD_TYPE_OSN)
-		hdr = (struct qeth_hdr *)skb->data;
-	else {
-		if (card->info.type == QETH_CARD_TYPE_IQD) {
-			new_skb = skb;
-			data_offset = ETH_HLEN;
-			hd_len = ETH_HLEN;
-			hdr = kmem_cache_alloc(qeth_core_header_cache,
-						GFP_ATOMIC);
-			if (!hdr)
-				goto tx_drop;
-			elements_needed++;
-			qeth_l2_fill_header(card, hdr, new_skb, cast_type);
-			hdr->hdr.l2.pkt_length = new_skb->len;
-			skb_copy_from_linear_data(new_skb,
-						  ((char *)hdr) + sizeof(*hdr),
-						  ETH_HLEN);
-		} else {
-			/* create a clone with writeable headroom */
-			new_skb = skb_realloc_headroom(skb,
-						sizeof(struct qeth_hdr));
-			if (!new_skb)
-				goto tx_drop;
-			hdr = skb_push(new_skb, sizeof(struct qeth_hdr));
-			qeth_l2_fill_header(card, hdr, new_skb, cast_type);
-			if (new_skb->ip_summed == CHECKSUM_PARTIAL)
-				qeth_l2_hdr_csum(card, hdr, new_skb);
-		}
+		if (rc)
+			return rc;
 	}
+	nr_frags = skb_shinfo(skb)->nr_frags;
 
-	elements = qeth_get_elements_no(card, new_skb, elements_needed,
-					(data_offset > 0) ? data_offset : 0);
+	rc = skb_cow_head(skb, push_len);
+	if (rc)
+		return rc;
+	push_len = qeth_push_hdr(skb, &hdr, push_len);
+	if (push_len < 0)
+		return push_len;
+	if (!push_len) {
+		/* hdr was allocated from cache */
+		hd_len = sizeof(*hdr);
+		hdr_elements = 1;
+	}
+	qeth_l2_fill_header(hdr, skb, cast_type, skb->len - push_len);
+	if (skb->ip_summed == CHECKSUM_PARTIAL)
+		qeth_l2_hdr_csum(card, hdr, skb);
+
+	elements = qeth_get_elements_no(card, skb, hdr_elements, 0);
 	if (!elements) {
-		if (data_offset >= 0)
-			kmem_cache_free(qeth_core_header_cache, hdr);
-		goto tx_drop;
+		rc = -E2BIG;
+		goto out;
 	}
+	elements += hdr_elements;
 
-	if (card->info.type != QETH_CARD_TYPE_IQD) {
-		if (qeth_hdr_chk_and_bounce(new_skb, &hdr,
-		    sizeof(struct qeth_hdr_layer2)))
-			goto tx_drop;
-		rc = qeth_do_send_packet(card, queue, new_skb, hdr,
-					 elements);
-	} else
-		rc = qeth_do_send_packet_fast(card, queue, new_skb, hdr,
-					      data_offset, hd_len);
+	/* TODO: remove the skb_orphan() once TX completion is fast enough */
+	skb_orphan(skb);
+	rc = qeth_do_send_packet(card, queue, skb, hdr, 0, hd_len, elements);
+out:
 	if (!rc) {
-		card->stats.tx_packets++;
-		card->stats.tx_bytes += tx_bytes;
 		if (card->options.performance_stats && nr_frags) {
 			card->perf_stats.sg_skbs_sent++;
 			/* nr_frags + skb->data */
 			card->perf_stats.sg_frags_sent += nr_frags + 1;
 		}
-		if (new_skb != skb)
-			dev_kfree_skb_any(skb);
-		rc = NETDEV_TX_OK;
 	} else {
-		if (data_offset >= 0)
+		if (hd_len)
 			kmem_cache_free(qeth_core_header_cache, hdr);
+		if (rc == -EBUSY)
+			/* roll back to ETH header */
+			skb_pull(skb, push_len);
+	}
+	return rc;
+}
 
-		if (rc == -EBUSY) {
-			if (new_skb != skb)
-				dev_kfree_skb_any(new_skb);
-			return NETDEV_TX_BUSY;
-		} else
-			goto tx_drop;
+static int qeth_l2_xmit_osn(struct qeth_card *card, struct sk_buff *skb,
+			    struct qeth_qdio_out_q *queue)
+{
+	unsigned int elements;
+	struct qeth_hdr *hdr;
+
+	if (skb->protocol == htons(ETH_P_IPV6))
+		return -EPROTONOSUPPORT;
+
+	hdr = (struct qeth_hdr *)skb->data;
+	elements = qeth_get_elements_no(card, skb, 0, 0);
+	if (!elements)
+		return -E2BIG;
+	if (qeth_hdr_chk_and_bounce(skb, &hdr, sizeof(*hdr)))
+		return -EINVAL;
+	return qeth_do_send_packet(card, queue, skb, hdr, 0, 0, elements);
+}
+
+static netdev_tx_t qeth_l2_hard_start_xmit(struct sk_buff *skb,
+					   struct net_device *dev)
+{
+	struct qeth_card *card = dev->ml_priv;
+	int cast_type = qeth_l2_get_cast_type(card, skb);
+	struct qeth_qdio_out_q *queue;
+	int tx_bytes = skb->len;
+	int rc;
+
+	if (card->qdio.do_prio_queueing || (cast_type &&
+					card->info.is_multicast_different))
+		queue = card->qdio.out_qs[qeth_get_priority_queue(card, skb,
+					qeth_get_ip_version(skb), cast_type)];
+	else
+		queue = card->qdio.out_qs[card->qdio.default_out_queue];
+
+	if ((card->state != CARD_STATE_UP) || !card->lan_online) {
+		card->stats.tx_carrier_errors++;
+		goto tx_drop;
 	}
 
-	netif_wake_queue(dev);
-	if (card->options.performance_stats)
-		card->perf_stats.outbound_time += qeth_get_micros() -
-			card->perf_stats.outbound_start_time;
-	return rc;
+	if (card->options.performance_stats) {
+		card->perf_stats.outbound_cnt++;
+		card->perf_stats.outbound_start_time = qeth_get_micros();
+	}
+	netif_stop_queue(dev);
+
+	switch (card->info.type) {
+	case QETH_CARD_TYPE_OSN:
+		rc = qeth_l2_xmit_osn(card, skb, queue);
+		break;
+	case QETH_CARD_TYPE_IQD:
+		rc = qeth_l2_xmit_iqd(card, skb, queue, cast_type);
+		break;
+	default:
+		rc = qeth_l2_xmit_osa(card, skb, queue, cast_type);
+	}
+
+	if (!rc) {
+		card->stats.tx_packets++;
+		card->stats.tx_bytes += tx_bytes;
+		if (card->options.performance_stats)
+			card->perf_stats.outbound_time += qeth_get_micros() -
+				card->perf_stats.outbound_start_time;
+		netif_wake_queue(dev);
+		return NETDEV_TX_OK;
+	} else if (rc == -EBUSY) {
+		return NETDEV_TX_BUSY;
+	} /* else fall through */
 
 tx_drop:
 	card->stats.tx_dropped++;
 	card->stats.tx_errors++;
-	if ((new_skb != skb) && new_skb)
-		dev_kfree_skb_any(new_skb);
 	dev_kfree_skb_any(skb);
 	netif_wake_queue(dev);
 	return NETDEV_TX_OK;
@@ -990,6 +1019,12 @@ static int qeth_l2_setup_netdev(struct qeth_card *card)
 			card->dev->vlan_features |= NETIF_F_RXCSUM;
 		}
 	}
+	if (card->info.type != QETH_CARD_TYPE_OSN &&
+	    card->info.type != QETH_CARD_TYPE_IQD) {
+		card->dev->priv_flags &= ~IFF_TX_SKB_SHARING;
+		card->dev->needed_headroom = sizeof(struct qeth_hdr);
+	}
+
 	card->info.broadcast_capable = 1;
 	qeth_l2_request_initial_mac(card);
 	card->dev->gso_max_size = (QETH_MAX_BUFFER_ELEMENTS(card) - 1) *

drivers/s390/net/qeth_l3_main.c

@@ -2637,6 +2637,7 @@ static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
 			qeth_get_priority_queue(card, skb, ipv, cast_type) :
 			card->qdio.default_out_queue];
 	int tx_bytes = skb->len;
+	unsigned int hd_len = 0;
 	bool use_tso;
 	int data_offset = -1;
 	unsigned int nr_frags;
@@ -2669,6 +2670,7 @@ static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
 	if (card->info.type == QETH_CARD_TYPE_IQD) {
 		new_skb = skb;
 		data_offset = ETH_HLEN;
+		hd_len = sizeof(*hdr);
 		hdr = kmem_cache_alloc(qeth_core_header_cache, GFP_ATOMIC);
 		if (!hdr)
 			goto tx_drop;
@@ -2756,19 +2758,21 @@ static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
 
 	if (card->info.type != QETH_CARD_TYPE_IQD) {
 		int len;
-		if (use_tso)
-			len = ((unsigned long)tcp_hdr(new_skb) +
-				tcp_hdrlen(new_skb)) -
-				(unsigned long)new_skb->data;
-		else
+		if (use_tso) {
+			hd_len = sizeof(struct qeth_hdr_tso) +
+				 ip_hdrlen(new_skb) + tcp_hdrlen(new_skb);
+			len = hd_len;
+		} else {
 			len = sizeof(struct qeth_hdr_layer3);
+		}
 
 		if (qeth_hdr_chk_and_bounce(new_skb, &hdr, len))
 			goto tx_drop;
-		rc = qeth_do_send_packet(card, queue, new_skb, hdr, elements);
+		rc = qeth_do_send_packet(card, queue, new_skb, hdr, hd_len,
+					 hd_len, elements);
 	} else
 		rc = qeth_do_send_packet_fast(card, queue, new_skb, hdr,
-					      data_offset, 0);
+					      data_offset, hd_len);
 
 	if (!rc) {
 		card->stats.tx_packets++;