be2net: fix a Tx stall bug caused by a specific ipv6 packet

The ASIC could lockup in the transmit path when it tries
to insert VLAN in a specific ipv6 packet.
1) Identify the packet which can cause this.
2) Check if the firmware provides a workaround to prevent this.
3) If workaround is not present, drop the packet.
4) If the firmware provides a workaround, insert the VLAN tag in the
packet and inform the firmware to skip further VLAN insertions.

Signed-off-by: Ajit Khaparde <ajit.khaparde@emulex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 92 insertions, 7 deletions

diff --git a/drivers/net/ethernet/emulex/benet/be_main.c b/drivers/net/ethernet/emulex/benet/be_main.c
index a254942ed5a..21109b59fcf 100644
--- a/drivers/net/ethernet/emulex/benet/be_main.c
+++ b/drivers/net/ethernet/emulex/benet/be_main.c
@@ -627,7 +627,7 @@ static inline u16 be_get_tx_vlan_tag(struct be_adapter *adapter,
 }
 
 static void wrb_fill_hdr(struct be_adapter *adapter, struct be_eth_hdr_wrb *hdr,
-		struct sk_buff *skb, u32 wrb_cnt, u32 len)
+		struct sk_buff *skb, u32 wrb_cnt, u32 len, bool skip_hw_vlan)
 {
 	u16 vlan_tag;
 
@@ -654,8 +654,9 @@ static void wrb_fill_hdr(struct be_adapter *adapter, struct be_eth_hdr_wrb *hdr,
 		AMAP_SET_BITS(struct amap_eth_hdr_wrb, vlan_tag, hdr, vlan_tag);
 	}
 
+	/* To skip HW VLAN tagging: evt = 1, compl = 0 */
+	AMAP_SET_BITS(struct amap_eth_hdr_wrb, complete, hdr, !skip_hw_vlan);
 	AMAP_SET_BITS(struct amap_eth_hdr_wrb, event, hdr, 1);
-	AMAP_SET_BITS(struct amap_eth_hdr_wrb, complete, hdr, 1);
 	AMAP_SET_BITS(struct amap_eth_hdr_wrb, num_wrb, hdr, wrb_cnt);
 	AMAP_SET_BITS(struct amap_eth_hdr_wrb, len, hdr, len);
 }
@@ -678,7 +679,8 @@ static void unmap_tx_frag(struct device *dev, struct be_eth_wrb *wrb,
 }
 
 static int make_tx_wrbs(struct be_adapter *adapter, struct be_queue_info *txq,
-		struct sk_buff *skb, u32 wrb_cnt, bool dummy_wrb)
+		struct sk_buff *skb, u32 wrb_cnt, bool dummy_wrb,
+		bool skip_hw_vlan)
 {
 	dma_addr_t busaddr;
 	int i, copied = 0;
@@ -727,7 +729,7 @@ static int make_tx_wrbs(struct be_adapter *adapter, struct be_queue_info *txq,
 		queue_head_inc(txq);
 	}
 
-	wrb_fill_hdr(adapter, hdr, first_skb, wrb_cnt, copied);
+	wrb_fill_hdr(adapter, hdr, first_skb, wrb_cnt, copied, skip_hw_vlan);
 	be_dws_cpu_to_le(hdr, sizeof(*hdr));
 
 	return copied;
@@ -744,7 +746,8 @@ dma_err:
 }
 
 static struct sk_buff *be_insert_vlan_in_pkt(struct be_adapter *adapter,
-					     struct sk_buff *skb)
+					     struct sk_buff *skb,
+					     bool *skip_hw_vlan)
 {
 	u16 vlan_tag = 0;
 
@@ -759,9 +762,67 @@ static struct sk_buff *be_insert_vlan_in_pkt(struct be_adapter *adapter,
 			skb->vlan_tci = 0;
 	}
 
+	if (qnq_async_evt_rcvd(adapter) && adapter->pvid) {
+		if (!vlan_tag)
+			vlan_tag = adapter->pvid;
+		if (skip_hw_vlan)
+			*skip_hw_vlan = true;
+	}
+
+	if (vlan_tag) {
+		skb = __vlan_put_tag(skb, vlan_tag);
+		if (unlikely(!skb))
+			return skb;
+
+		skb->vlan_tci = 0;
+	}
+
+	/* Insert the outer VLAN, if any */
+	if (adapter->qnq_vid) {
+		vlan_tag = adapter->qnq_vid;
+		skb = __vlan_put_tag(skb, vlan_tag);
+		if (unlikely(!skb))
+			return skb;
+		if (skip_hw_vlan)
+			*skip_hw_vlan = true;
+	}
+
 	return skb;
 }
 
+static bool be_ipv6_exthdr_check(struct sk_buff *skb)
+{
+	struct ethhdr *eh = (struct ethhdr *)skb->data;
+	u16 offset = ETH_HLEN;
+
+	if (eh->h_proto == htons(ETH_P_IPV6)) {
+		struct ipv6hdr *ip6h = (struct ipv6hdr *)(skb->data + offset);
+
+		offset += sizeof(struct ipv6hdr);
+		if (ip6h->nexthdr != NEXTHDR_TCP &&
+		    ip6h->nexthdr != NEXTHDR_UDP) {
+			struct ipv6_opt_hdr *ehdr =
+				(struct ipv6_opt_hdr *) (skb->data + offset);
+
+			/* offending pkt: 2nd byte following IPv6 hdr is 0xff */
+			if (ehdr->hdrlen == 0xff)
+				return true;
+		}
+	}
+	return false;
+}
+
+static int be_vlan_tag_tx_chk(struct be_adapter *adapter, struct sk_buff *skb)
+{
+	return vlan_tx_tag_present(skb) || adapter->pvid || adapter->qnq_vid;
+}
+
+static int be_ipv6_tx_stall_chk(struct be_adapter *adapter, struct sk_buff *skb)
+{
+	return BE3_chip(adapter) &&
+		be_ipv6_exthdr_check(skb);
+}
+
 static netdev_tx_t be_xmit(struct sk_buff *skb,
 			struct net_device *netdev)
 {
@@ -772,6 +833,7 @@ static netdev_tx_t be_xmit(struct sk_buff *skb,
 	u32 wrb_cnt = 0, copied = 0;
 	u32 start = txq->head, eth_hdr_len;
 	bool dummy_wrb, stopped = false;
+	bool skip_hw_vlan = false;
 
 	eth_hdr_len = ntohs(skb->protocol) == ETH_P_8021Q ?
 		VLAN_ETH_HLEN : ETH_HLEN;
@@ -790,14 +852,37 @@ static netdev_tx_t be_xmit(struct sk_buff *skb,
 	 */
 	if (skb->ip_summed != CHECKSUM_PARTIAL &&
 			vlan_tx_tag_present(skb)) {
-		skb = be_insert_vlan_in_pkt(adapter, skb);
+		skb = be_insert_vlan_in_pkt(adapter, skb, &skip_hw_vlan);
+		if (unlikely(!skb))
+			goto tx_drop;
+	}
+
+	/* HW may lockup when VLAN HW tagging is requested on
+	 * certain ipv6 packets. Drop such pkts if the HW workaround to
+	 * skip HW tagging is not enabled by FW.
+	 */
+	if (unlikely(be_ipv6_tx_stall_chk(adapter, skb) &&
+		     (adapter->pvid || adapter->qnq_vid) &&
+		     !qnq_async_evt_rcvd(adapter)))
+		goto tx_drop;
+
+	/* Manual VLAN tag insertion to prevent:
+	 * ASIC lockup when the ASIC inserts VLAN tag into
+	 * certain ipv6 packets. Insert VLAN tags in driver,
+	 * and set event, completion, vlan bits accordingly
+	 * in the Tx WRB.
+	 */
+	if (be_ipv6_tx_stall_chk(adapter, skb) &&
+	    be_vlan_tag_tx_chk(adapter, skb)) {
+		skb = be_insert_vlan_in_pkt(adapter, skb, &skip_hw_vlan);
 		if (unlikely(!skb))
 			goto tx_drop;
 	}
 
 	wrb_cnt = wrb_cnt_for_skb(adapter, skb, &dummy_wrb);
 
-	copied = make_tx_wrbs(adapter, txq, skb, wrb_cnt, dummy_wrb);
+	copied = make_tx_wrbs(adapter, txq, skb, wrb_cnt, dummy_wrb,
+			      skip_hw_vlan);
 	if (copied) {
 		int gso_segs = skb_shinfo(skb)->gso_segs;