svn commit: r362310 - stable/10/sys/dev/mlx5/mlx5_en

[Hans Petter Selasky]

Author: hselasky
Date: Thu Jun 18 10:31:21 2020
New Revision: 362310
URL: https://svnweb.freebsd.org/changeset/base/362310

Log:
  MFC r362044:
  Extend use of unlikely() in the fast path, in mlx5en(4).
  
  Typically the TCP/IP headers fit within the first mbuf and should not
  trigger any of the error cases. Use unlikely() for these cases.
  
  No functional change.
  
  Sponsored by:	Mellanox Technologies

Modified:
  stable/10/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c
Directory Properties:
  stable/10/   (props changed)

Modified: stable/10/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c
==============================================================================
--- stable/10/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c	Thu Jun 18 10:20:16 2020	(r362309)
+++ stable/10/sys/dev/mlx5/mlx5_en/mlx5_en_tx.c	Thu Jun 18 10:31:21 2020	(r362310)
@@ -196,21 +196,21 @@ mlx5e_get_header_size(const struct mbuf *mb)
 	int eth_hdr_len;
 
 	eh = mtod(mb, const struct ether_vlan_header *);
-	if (mb->m_len < ETHER_HDR_LEN)
+	if (unlikely(mb->m_len < ETHER_HDR_LEN))
 		return (0);
 	if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN)) {
+		if (unlikely(mb->m_len < (ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN)))
+			return (0);
 		eth_type = ntohs(eh->evl_proto);
 		eth_hdr_len = ETHER_HDR_LEN + ETHER_VLAN_ENCAP_LEN;
 	} else {
 		eth_type = ntohs(eh->evl_encap_proto);
 		eth_hdr_len = ETHER_HDR_LEN;
 	}
-	if (mb->m_len < eth_hdr_len)
-		return (0);
 	switch (eth_type) {
 	case ETHERTYPE_IP:
 		ip = (const struct ip *)(mb->m_data + eth_hdr_len);
-		if (mb->m_len < eth_hdr_len + sizeof(*ip))
+		if (unlikely(mb->m_len < eth_hdr_len + sizeof(*ip)))
 			return (0);
 		if (ip->ip_p != IPPROTO_TCP)
 			return (0);
@@ -219,7 +219,7 @@ mlx5e_get_header_size(const struct mbuf *mb)
 		break;
 	case ETHERTYPE_IPV6:
 		ip6 = (const struct ip6_hdr *)(mb->m_data + eth_hdr_len);
-		if (mb->m_len < eth_hdr_len + sizeof(*ip6))
+		if (unlikely(mb->m_len < eth_hdr_len + sizeof(*ip6)))
 			return (0);
 		if (ip6->ip6_nxt != IPPROTO_TCP)
 			return (0);
@@ -228,12 +228,17 @@ mlx5e_get_header_size(const struct mbuf *mb)
 	default:
 		return (0);
 	}
-	if (mb->m_len < eth_hdr_len + sizeof(*th))
+	if (unlikely(mb->m_len < eth_hdr_len + sizeof(*th)))
 		return (0);
 	th = (const struct tcphdr *)(mb->m_data + eth_hdr_len);
 	tcp_hlen = th->th_off << 2;
 	eth_hdr_len += tcp_hlen;
-	if (mb->m_len < eth_hdr_len)
+	/*
+	 * m_copydata() will be used on the remaining header which
+	 * does not need to reside within the first m_len bytes of
+	 * data:
+	 */
+	if (unlikely(mb->m_pkthdr.len < eth_hdr_len))
 		return (0);
 	return (eth_hdr_len);
 }