netdev - [PATCH net-next 10/12] s390/qeth: consolidate skb RX processing in L3 driver

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Date:   Thu, 27 Jun 2019 17:01:31 +0200
From:   Julian Wiedmann <jwi@...ux.ibm.com>
To:     David Miller <davem@...emloft.net>
Cc:     <netdev@...r.kernel.org>, <linux-s390@...r.kernel.org>,
        Heiko Carstens <heiko.carstens@...ibm.com>,
        Stefan Raspl <raspl@...ux.ibm.com>,
        Ursula Braun <ubraun@...ux.ibm.com>,
        Julian Wiedmann <jwi@...ux.ibm.com>
Subject: [PATCH net-next 10/12] s390/qeth: consolidate skb RX processing in L3 driver

Use napi_gro_receive() to pass up all types of packets that a L3 device
may receive.
1) For proper L2 packets received by the IQD sniffer, this is the
   obvious thing to do.
2) For af_iucv (which doesn't provide a GRO assist), the GRO code will
   transparently fall back to netif_receive_skb(). So there's no need to
   special-case this traffic in our code.

Signed-off-by: Julian Wiedmann <jwi@...ux.ibm.com>
---
 drivers/s390/net/qeth_l3_main.c | 30 ++++++++++++------------------
 1 file changed, 12 insertions(+), 18 deletions(-)

diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 44a602aa12ec..15351922b209 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -1312,6 +1312,15 @@ static int qeth_l3_vlan_rx_kill_vid(struct net_device *dev,
 static void qeth_l3_rebuild_skb(struct qeth_card *card, struct sk_buff *skb,
 				struct qeth_hdr *hdr)
 {
+	struct af_iucv_trans_hdr *iucv = (struct af_iucv_trans_hdr *) skb->data;
+	struct net_device *dev = skb->dev;
+
+	if (IS_IQD(card) && iucv->magic == ETH_P_AF_IUCV) {
+		dev_hard_header(skb, dev, ETH_P_AF_IUCV, dev->dev_addr,
+				"FAKELL", skb->len);
+		return;
+	}
+
 	if (!(hdr->hdr.l3.flags & QETH_HDR_PASSTHRU)) {
 		u16 prot = (hdr->hdr.l3.flags & QETH_HDR_IPV6) ? ETH_P_IPV6 :
 								 ETH_P_IP;
@@ -1345,8 +1354,6 @@ static void qeth_l3_rebuild_skb(struct qeth_card *card, struct sk_buff *skb,
 				tg_addr, "FAKELL", skb->len);
 	}
 
-	skb->protocol = eth_type_trans(skb, card->dev);
-
 	/* copy VLAN tag from hdr into skb */
 	if (!card->options.sniffer &&
 	    (hdr->hdr.l3.ext_flags & (QETH_HDR_EXT_VLAN_FRAME |
@@ -1363,12 +1370,10 @@ static void qeth_l3_rebuild_skb(struct qeth_card *card, struct sk_buff *skb,
 static int qeth_l3_process_inbound_buffer(struct qeth_card *card,
 				int budget, int *done)
 {
-	struct net_device *dev = card->dev;
 	int work_done = 0;
 	struct sk_buff *skb;
 	struct qeth_hdr *hdr;
 	unsigned int len;
-	__u16 magic;
 
 	*done = 0;
 	WARN_ON_ONCE(!budget);
@@ -1382,23 +1387,12 @@ static int qeth_l3_process_inbound_buffer(struct qeth_card *card,
 		}
 		switch (hdr->hdr.l3.id) {
 		case QETH_HEADER_TYPE_LAYER3:
-			magic = *(__u16 *)skb->data;
-			if (IS_IQD(card) && magic == ETH_P_AF_IUCV) {
-				len = skb->len;
-				dev_hard_header(skb, dev, ETH_P_AF_IUCV,
-						dev->dev_addr, "FAKELL", len);
-				skb->protocol = eth_type_trans(skb, dev);
-				netif_receive_skb(skb);
-			} else {
-				qeth_l3_rebuild_skb(card, skb, hdr);
-				len = skb->len;
-				napi_gro_receive(&card->napi, skb);
-			}
-			break;
+			qeth_l3_rebuild_skb(card, skb, hdr);
+			/* fall through */
 		case QETH_HEADER_TYPE_LAYER2: /* for HiperSockets sniffer */
 			skb->protocol = eth_type_trans(skb, skb->dev);
 			len = skb->len;
-			netif_receive_skb(skb);
+			napi_gro_receive(&card->napi, skb);
 			break;
 		default:
 			dev_kfree_skb_any(skb);
-- 
2.17.1