[PATCH net-next v2 0/3] Drop get_headlen functions in favor of generic function

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8 messages, 4 authors, 2014-09-06 · open the first message on its own page

[PATCH net-next v2 0/3] Drop get_headlen functions in favor of generic function

From: Alexander Duyck <hidden>
Date: 2014-09-05 23:28:43

This series replaces the igb_get_headlen and ixgbe_get_headlen functions
with a generic function named eth_get_headlen.

I have done some performance testing on ixgbe with 258 byte frames since
the calls are only used on frames larger than 256 bytes and have seen no
significant difference in CPU utilization.

v2: renamed __skb_get_poff to skb_get_poff
    renamed ___skb_get_poff to __skb_get_poff

---

Alexander Duyck (3):
      net: Add function for parsing the header length out of linear ethernet frames
      igb: use new eth_get_headlen interface
      ixgbe: use new eth_get_headlen interface


 drivers/net/ethernet/intel/igb/igb_main.c     |  109 -----------------------
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  116 -------------------------
 include/linux/etherdevice.h                   |    1 
 include/linux/skbuff.h                        |    4 +
 include/net/flow_keys.h                       |    2 
 net/core/filter.c                             |    2 
 net/core/flow_dissector.c                     |   46 +++++++---
 net/ethernet/eth.c                            |   27 ++++++
 8 files changed, 68 insertions(+), 239 deletions(-)

-- 

[PATCH net-next v2 2/3] igb: use new eth_get_headlen interface

From: Alexander Duyck <hidden>
Date: 2014-09-05 23:29:19

Update igb to drop the igb_get_headlen function in favor of eth_get_headlen.

Signed-off-by: Alexander Duyck <redacted>
---
 drivers/net/ethernet/intel/igb/igb_main.c |  109 -----------------------------
 1 file changed, 1 insertion(+), 108 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 89de7fe..4c023f0 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6769,113 +6769,6 @@ static bool igb_is_non_eop(struct igb_ring *rx_ring,
 }
 
 /**
- *  igb_get_headlen - determine size of header for LRO/GRO
- *  @data: pointer to the start of the headers
- *  @max_len: total length of section to find headers in
- *
- *  This function is meant to determine the length of headers that will
- *  be recognized by hardware for LRO, and GRO offloads.  The main
- *  motivation of doing this is to only perform one pull for IPv4 TCP
- *  packets so that we can do basic things like calculating the gso_size
- *  based on the average data per packet.
- **/
-static unsigned int igb_get_headlen(unsigned char *data,
-				    unsigned int max_len)
-{
-	union {
-		unsigned char *network;
-		/* l2 headers */
-		struct ethhdr *eth;
-		struct vlan_hdr *vlan;
-		/* l3 headers */
-		struct iphdr *ipv4;
-		struct ipv6hdr *ipv6;
-	} hdr;
-	__be16 protocol;
-	u8 nexthdr = 0;	/* default to not TCP */
-	u8 hlen;
-
-	/* this should never happen, but better safe than sorry */
-	if (max_len < ETH_HLEN)
-		return max_len;
-
-	/* initialize network frame pointer */
-	hdr.network = data;
-
-	/* set first protocol and move network header forward */
-	protocol = hdr.eth->h_proto;
-	hdr.network += ETH_HLEN;
-
-	/* handle any vlan tag if present */
-	if (protocol == htons(ETH_P_8021Q)) {
-		if ((hdr.network - data) > (max_len - VLAN_HLEN))
-			return max_len;
-
-		protocol = hdr.vlan->h_vlan_encapsulated_proto;
-		hdr.network += VLAN_HLEN;
-	}
-
-	/* handle L3 protocols */
-	if (protocol == htons(ETH_P_IP)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct iphdr)))
-			return max_len;
-
-		/* access ihl as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[0] & 0x0F) << 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct iphdr))
-			return hdr.network - data;
-
-		/* record next protocol if header is present */
-		if (!(hdr.ipv4->frag_off & htons(IP_OFFSET)))
-			nexthdr = hdr.ipv4->protocol;
-	} else if (protocol == htons(ETH_P_IPV6)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct ipv6hdr)))
-			return max_len;
-
-		/* record next protocol */
-		nexthdr = hdr.ipv6->nexthdr;
-		hlen = sizeof(struct ipv6hdr);
-	} else {
-		return hdr.network - data;
-	}
-
-	/* relocate pointer to start of L4 header */
-	hdr.network += hlen;
-
-	/* finally sort out TCP */
-	if (nexthdr == IPPROTO_TCP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct tcphdr)))
-			return max_len;
-
-		/* access doff as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[12] & 0xF0) >> 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct tcphdr))
-			return hdr.network - data;
-
-		hdr.network += hlen;
-	} else if (nexthdr == IPPROTO_UDP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct udphdr)))
-			return max_len;
-
-		hdr.network += sizeof(struct udphdr);
-	}
-
-	/* If everything has gone correctly hdr.network should be the
-	 * data section of the packet and will be the end of the header.
-	 * If not then it probably represents the end of the last recognized
-	 * header.
-	 */
-	if ((hdr.network - data) < max_len)
-		return hdr.network - data;
-	else
-		return max_len;
-}
-
-/**
  *  igb_pull_tail - igb specific version of skb_pull_tail
  *  @rx_ring: rx descriptor ring packet is being transacted on
  *  @rx_desc: pointer to the EOP Rx descriptor
@@ -6919,7 +6812,7 @@ static void igb_pull_tail(struct igb_ring *rx_ring,
 	/* we need the header to contain the greater of either ETH_HLEN or
 	 * 60 bytes if the skb->len is less than 60 for skb_pad.
 	 */
-	pull_len = igb_get_headlen(va, IGB_RX_HDR_LEN);
+	pull_len = eth_get_headlen(va, IGB_RX_HDR_LEN);
 
 	/* align pull length to size of long to optimize memcpy performance */
 	skb_copy_to_linear_data(skb, va, ALIGN(pull_len, sizeof(long)));

[PATCH net-next v2 1/3] net: Add function for parsing the header length out of linear ethernet frames

From: Alexander Duyck <hidden>
Date: 2014-09-05 23:29:23

This patch updates some of the flow_dissector api so that it can be used to
parse the length of ethernet buffers stored in fragments.  Most of the
changes needed were to __skb_get_poff as it needed to be updated to support
sending a linear buffer instead of a skb.

I have split __skb_get_poff into two functions, the first is skb_get_poff
and it retains the functionality of the original __skb_get_poff.  The other
function is __skb_get_poff which now works much like __skb_flow_dissect in
relation to skb_flow_dissect in that it provides the same functionality but
works with just a data buffer and hlen instead of needing an skb.

Signed-off-by: Alexander Duyck <redacted>
---
 include/linux/etherdevice.h |    1 +
 include/linux/skbuff.h      |    4 +++-
 include/net/flow_keys.h     |    2 ++
 net/core/filter.c           |    2 +-
 net/core/flow_dissector.c   |   46 ++++++++++++++++++++++++++++++-------------
 net/ethernet/eth.c          |   27 +++++++++++++++++++++++++
 6 files changed, 66 insertions(+), 16 deletions(-)
diff --git a/include/linux/etherdevice.h b/include/linux/etherdevice.h
index 9c5529d..733980f 100644
--- a/include/linux/etherdevice.h
+++ b/include/linux/etherdevice.h
@@ -29,6 +29,7 @@
 #include <asm/bitsperlong.h>
 
 #ifdef __KERNEL__
+u32 eth_get_headlen(void *data, unsigned int max_len);
 __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev);
 extern const struct header_ops eth_header_ops;
 
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 02529fc..72fcc90 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -3216,7 +3216,9 @@ bool skb_partial_csum_set(struct sk_buff *skb, u16 start, u16 off);
 
 int skb_checksum_setup(struct sk_buff *skb, bool recalculate);
 
-u32 __skb_get_poff(const struct sk_buff *skb);
+u32 skb_get_poff(const struct sk_buff *skb);
+u32 __skb_get_poff(const struct sk_buff *skb, void *data,
+	 	   const struct flow_keys *keys, int hlen);
 
 /**
  * skb_head_is_locked - Determine if the skb->head is locked down
diff --git a/include/net/flow_keys.h b/include/net/flow_keys.h
index 9a03f73..7ee2df0 100644
--- a/include/net/flow_keys.h
+++ b/include/net/flow_keys.h
@@ -40,4 +40,6 @@ static inline __be32 skb_flow_get_ports(const struct sk_buff *skb, int thoff, u8
 	return __skb_flow_get_ports(skb, thoff, ip_proto, NULL, 0);
 }
 u32 flow_hash_from_keys(struct flow_keys *keys);
+unsigned int flow_get_hlen(const unsigned char *data, unsigned int max_len,
+			   __be16 protocol);
 #endif
diff --git a/net/core/filter.c b/net/core/filter.c
index d814b8a..613409e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -113,7 +113,7 @@ static unsigned int pkt_type_offset(void)
 
 static u64 __skb_get_pay_offset(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
 {
-	return __skb_get_poff((struct sk_buff *)(unsigned long) ctx);
+	return skb_get_poff((struct sk_buff *)(unsigned long) ctx);
 }
 
 static u64 __skb_get_nlattr(u64 ctx, u64 a, u64 x, u64 r4, u64 r5)
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 12f48ca..8e5decb 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -13,6 +13,7 @@
 #include <linux/if_pppox.h>
 #include <linux/ppp_defs.h>
 #include <net/flow_keys.h>
+#include <scsi/fc/fc_fcoe.h>
 
 /* copy saddr & daddr, possibly using 64bit load/store
  * Equivalent to :	flow->src = iph->saddr;
@@ -117,6 +118,13 @@ ipv6:
 		flow->dst = (__force __be32)ipv6_addr_hash(&iph->daddr);
 		nhoff += sizeof(struct ipv6hdr);
 
+		/* skip the flow label processing if skb is NULL.  The
+		 * assumption here is that if there is no skb we are not
+		 * looking for flow info as much as we are length.
+		 */
+		if (!skb)
+			break;
+
 		flow_label = ip6_flowlabel(iph);
 		if (flow_label) {
 			/* Awesome, IPv6 packet has a flow label so we can
@@ -165,6 +173,9 @@ ipv6:
 			return false;
 		}
 	}
+	case htons(ETH_P_FCOE):
+		flow->thoff = (u16)(nhoff + FCOE_HEADER_LEN);
+		/* fall through */
 	default:
 		return false;
 	}
@@ -316,26 +327,18 @@ u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb,
 }
 EXPORT_SYMBOL(__skb_tx_hash);
 
-/* __skb_get_poff() returns the offset to the payload as far as it could
- * be dissected. The main user is currently BPF, so that we can dynamically
- * truncate packets without needing to push actual payload to the user
- * space and can analyze headers only, instead.
- */
-u32 __skb_get_poff(const struct sk_buff *skb)
+u32 __skb_get_poff(const struct sk_buff *skb, void *data,
+	 	   const struct flow_keys *keys, int hlen)
 {
-	struct flow_keys keys;
-	u32 poff = 0;
+	u32 poff = keys->thoff;
 
-	if (!skb_flow_dissect(skb, &keys))
-		return 0;
-
-	poff += keys.thoff;
-	switch (keys.ip_proto) {
+	switch (keys->ip_proto) {
 	case IPPROTO_TCP: {
 		const struct tcphdr *tcph;
 		struct tcphdr _tcph;
 
-		tcph = skb_header_pointer(skb, poff, sizeof(_tcph), &_tcph);
+		tcph = __skb_header_pointer(skb, poff, sizeof(_tcph),
+					    data, hlen, &_tcph);
 		if (!tcph)
 			return poff;
 
@@ -369,6 +372,21 @@ u32 __skb_get_poff(const struct sk_buff *skb)
 	return poff;
 }
 
+/* skb_get_poff() returns the offset to the payload as far as it could
+ * be dissected. The main user is currently BPF, so that we can dynamically
+ * truncate packets without needing to push actual payload to the user
+ * space and can analyze headers only, instead.
+ */
+u32 skb_get_poff(const struct sk_buff *skb)
+{
+	struct flow_keys keys;
+
+	if (!skb_flow_dissect(skb, &keys))
+		return 0;
+
+	return __skb_get_poff(skb, skb->data, &keys, skb_headlen(skb));
+}
+
 static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
 {
 #ifdef CONFIG_XPS
diff --git a/net/ethernet/eth.c b/net/ethernet/eth.c
index 5cebca1..33a140e 100644
--- a/net/ethernet/eth.c
+++ b/net/ethernet/eth.c
@@ -146,6 +146,33 @@ int eth_rebuild_header(struct sk_buff *skb)
 EXPORT_SYMBOL(eth_rebuild_header);
 
 /**
+ * eth_get_headlen - determine the the length of header for an ethernet frame
+ * @data: pointer to start of frame
+ * @len: total length of frame
+ *
+ * Make a best effort attempt to pull the length for all of the headers for
+ * a given frame in a linear buffer.
+ */
+u32 eth_get_headlen(void *data, unsigned int len)
+{
+	const struct ethhdr *eth = (const struct ethhdr *)data;
+	struct flow_keys keys;
+
+	/* this should never happen, but better safe than sorry */
+	if (len < sizeof(*eth))
+		return len;
+
+	/* parse any remaining L2/L3 headers, check for L4 */
+	if (!__skb_flow_dissect(NULL, &keys, data,
+				eth->h_proto, sizeof(*eth), len))
+		return max_t(u32, keys.thoff, sizeof(*eth));
+
+	/* parse for any L4 headers */
+	return min_t(u32, __skb_get_poff(NULL, data, &keys, len), len);
+}
+EXPORT_SYMBOL(eth_get_headlen);
+
+/**
  * eth_type_trans - determine the packet's protocol ID.
  * @skb: received socket data
  * @dev: receiving network device

[PATCH net-next v2 3/3] ixgbe: use new eth_get_headlen interface

From: Alexander Duyck <hidden>
Date: 2014-09-05 23:30:49

Update ixgbe to drop the ixgbe_get_headlen function in favor of eth_get_headlen.

Signed-off-by: Alexander Duyck <redacted>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  116 -------------------------
 1 file changed, 1 insertion(+), 115 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 53fbf06..09c3746 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1521,120 +1521,6 @@ void ixgbe_alloc_rx_buffers(struct ixgbe_ring *rx_ring, u16 cleaned_count)
 		ixgbe_release_rx_desc(rx_ring, i);
 }
 
-/**
- * ixgbe_get_headlen - determine size of header for RSC/LRO/GRO/FCOE
- * @data: pointer to the start of the headers
- * @max_len: total length of section to find headers in
- *
- * This function is meant to determine the length of headers that will
- * be recognized by hardware for LRO, GRO, and RSC offloads.  The main
- * motivation of doing this is to only perform one pull for IPv4 TCP
- * packets so that we can do basic things like calculating the gso_size
- * based on the average data per packet.
- **/
-static unsigned int ixgbe_get_headlen(unsigned char *data,
-				      unsigned int max_len)
-{
-	union {
-		unsigned char *network;
-		/* l2 headers */
-		struct ethhdr *eth;
-		struct vlan_hdr *vlan;
-		/* l3 headers */
-		struct iphdr *ipv4;
-		struct ipv6hdr *ipv6;
-	} hdr;
-	__be16 protocol;
-	u8 nexthdr = 0;	/* default to not TCP */
-	u8 hlen;
-
-	/* this should never happen, but better safe than sorry */
-	if (max_len < ETH_HLEN)
-		return max_len;
-
-	/* initialize network frame pointer */
-	hdr.network = data;
-
-	/* set first protocol and move network header forward */
-	protocol = hdr.eth->h_proto;
-	hdr.network += ETH_HLEN;
-
-	/* handle any vlan tag if present */
-	if (protocol == htons(ETH_P_8021Q)) {
-		if ((hdr.network - data) > (max_len - VLAN_HLEN))
-			return max_len;
-
-		protocol = hdr.vlan->h_vlan_encapsulated_proto;
-		hdr.network += VLAN_HLEN;
-	}
-
-	/* handle L3 protocols */
-	if (protocol == htons(ETH_P_IP)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct iphdr)))
-			return max_len;
-
-		/* access ihl as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[0] & 0x0F) << 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct iphdr))
-			return hdr.network - data;
-
-		/* record next protocol if header is present */
-		if (!(hdr.ipv4->frag_off & htons(IP_OFFSET)))
-			nexthdr = hdr.ipv4->protocol;
-	} else if (protocol == htons(ETH_P_IPV6)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct ipv6hdr)))
-			return max_len;
-
-		/* record next protocol */
-		nexthdr = hdr.ipv6->nexthdr;
-		hlen = sizeof(struct ipv6hdr);
-#ifdef IXGBE_FCOE
-	} else if (protocol == htons(ETH_P_FCOE)) {
-		if ((hdr.network - data) > (max_len - FCOE_HEADER_LEN))
-			return max_len;
-		hlen = FCOE_HEADER_LEN;
-#endif
-	} else {
-		return hdr.network - data;
-	}
-
-	/* relocate pointer to start of L4 header */
-	hdr.network += hlen;
-
-	/* finally sort out TCP/UDP */
-	if (nexthdr == IPPROTO_TCP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct tcphdr)))
-			return max_len;
-
-		/* access doff as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[12] & 0xF0) >> 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct tcphdr))
-			return hdr.network - data;
-
-		hdr.network += hlen;
-	} else if (nexthdr == IPPROTO_UDP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct udphdr)))
-			return max_len;
-
-		hdr.network += sizeof(struct udphdr);
-	}
-
-	/*
-	 * If everything has gone correctly hdr.network should be the
-	 * data section of the packet and will be the end of the header.
-	 * If not then it probably represents the end of the last recognized
-	 * header.
-	 */
-	if ((hdr.network - data) < max_len)
-		return hdr.network - data;
-	else
-		return max_len;
-}
-
 static void ixgbe_set_rsc_gso_size(struct ixgbe_ring *ring,
 				   struct sk_buff *skb)
 {
@@ -1793,7 +1679,7 @@ static void ixgbe_pull_tail(struct ixgbe_ring *rx_ring,
 	 * we need the header to contain the greater of either ETH_HLEN or
 	 * 60 bytes if the skb->len is less than 60 for skb_pad.
 	 */
-	pull_len = ixgbe_get_headlen(va, IXGBE_RX_HDR_SIZE);
+	pull_len = eth_get_headlen(va, IXGBE_RX_HDR_SIZE);
 
 	/* align pull length to size of long to optimize memcpy performance */
 	skb_copy_to_linear_data(skb, va, ALIGN(pull_len, sizeof(long)));

Re: [PATCH net-next v2 2/3] igb: use new eth_get_headlen interface

From: Jeff Kirsher <hidden>
Date: 2014-09-05 23:34:26

On Fri, 2014-09-05 at 19:20 -0400, Alexander Duyck wrote:
Update igb to drop the igb_get_headlen function in favor of eth_get_headlen.

Signed-off-by: Alexander Duyck <redacted>
Acked-by:  Jeff Kirsher <redacted>
quoted hunk
---
 drivers/net/ethernet/intel/igb/igb_main.c |  109 -----------------------------
 1 file changed, 1 insertion(+), 108 deletions(-)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 89de7fe..4c023f0 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -6769,113 +6769,6 @@ static bool igb_is_non_eop(struct igb_ring *rx_ring,
 }
 
 /**
- *  igb_get_headlen - determine size of header for LRO/GRO
- *  @data: pointer to the start of the headers
- *  @max_len: total length of section to find headers in
- *
- *  This function is meant to determine the length of headers that will
- *  be recognized by hardware for LRO, and GRO offloads.  The main
- *  motivation of doing this is to only perform one pull for IPv4 TCP
- *  packets so that we can do basic things like calculating the gso_size
- *  based on the average data per packet.
- **/
-static unsigned int igb_get_headlen(unsigned char *data,
-				    unsigned int max_len)
-{
-	union {
-		unsigned char *network;
-		/* l2 headers */
-		struct ethhdr *eth;
-		struct vlan_hdr *vlan;
-		/* l3 headers */
-		struct iphdr *ipv4;
-		struct ipv6hdr *ipv6;
-	} hdr;
-	__be16 protocol;
-	u8 nexthdr = 0;	/* default to not TCP */
-	u8 hlen;
-
-	/* this should never happen, but better safe than sorry */
-	if (max_len < ETH_HLEN)
-		return max_len;
-
-	/* initialize network frame pointer */
-	hdr.network = data;
-
-	/* set first protocol and move network header forward */
-	protocol = hdr.eth->h_proto;
-	hdr.network += ETH_HLEN;
-
-	/* handle any vlan tag if present */
-	if (protocol == htons(ETH_P_8021Q)) {
-		if ((hdr.network - data) > (max_len - VLAN_HLEN))
-			return max_len;
-
-		protocol = hdr.vlan->h_vlan_encapsulated_proto;
-		hdr.network += VLAN_HLEN;
-	}
-
-	/* handle L3 protocols */
-	if (protocol == htons(ETH_P_IP)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct iphdr)))
-			return max_len;
-
-		/* access ihl as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[0] & 0x0F) << 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct iphdr))
-			return hdr.network - data;
-
-		/* record next protocol if header is present */
-		if (!(hdr.ipv4->frag_off & htons(IP_OFFSET)))
-			nexthdr = hdr.ipv4->protocol;
-	} else if (protocol == htons(ETH_P_IPV6)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct ipv6hdr)))
-			return max_len;
-
-		/* record next protocol */
-		nexthdr = hdr.ipv6->nexthdr;
-		hlen = sizeof(struct ipv6hdr);
-	} else {
-		return hdr.network - data;
-	}
-
-	/* relocate pointer to start of L4 header */
-	hdr.network += hlen;
-
-	/* finally sort out TCP */
-	if (nexthdr == IPPROTO_TCP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct tcphdr)))
-			return max_len;
-
-		/* access doff as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[12] & 0xF0) >> 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct tcphdr))
-			return hdr.network - data;
-
-		hdr.network += hlen;
-	} else if (nexthdr == IPPROTO_UDP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct udphdr)))
-			return max_len;
-
-		hdr.network += sizeof(struct udphdr);
-	}
-
-	/* If everything has gone correctly hdr.network should be the
-	 * data section of the packet and will be the end of the header.
-	 * If not then it probably represents the end of the last recognized
-	 * header.
-	 */
-	if ((hdr.network - data) < max_len)
-		return hdr.network - data;
-	else
-		return max_len;
-}
-
-/**
  *  igb_pull_tail - igb specific version of skb_pull_tail
  *  @rx_ring: rx descriptor ring packet is being transacted on
  *  @rx_desc: pointer to the EOP Rx descriptor
@@ -6919,7 +6812,7 @@ static void igb_pull_tail(struct igb_ring *rx_ring,
 	/* we need the header to contain the greater of either ETH_HLEN or
 	 * 60 bytes if the skb->len is less than 60 for skb_pad.
 	 */
-	pull_len = igb_get_headlen(va, IGB_RX_HDR_LEN);
+	pull_len = eth_get_headlen(va, IGB_RX_HDR_LEN);
 
 	/* align pull length to size of long to optimize memcpy performance */
 	skb_copy_to_linear_data(skb, va, ALIGN(pull_len, sizeof(long)));

Re: [PATCH net-next v2 3/3] ixgbe: use new eth_get_headlen interface

From: Jeff Kirsher <hidden>
Date: 2014-09-05 23:35:13

On Fri, 2014-09-05 at 19:22 -0400, Alexander Duyck wrote:
Update ixgbe to drop the ixgbe_get_headlen function in favor of eth_get_headlen.

Signed-off-by: Alexander Duyck <redacted>
Acked-by: Jeff Kirsher <redacted>
quoted hunk
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  116 -------------------------
 1 file changed, 1 insertion(+), 115 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index 53fbf06..09c3746 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1521,120 +1521,6 @@ void ixgbe_alloc_rx_buffers(struct ixgbe_ring *rx_ring, u16 cleaned_count)
 		ixgbe_release_rx_desc(rx_ring, i);
 }
 
-/**
- * ixgbe_get_headlen - determine size of header for RSC/LRO/GRO/FCOE
- * @data: pointer to the start of the headers
- * @max_len: total length of section to find headers in
- *
- * This function is meant to determine the length of headers that will
- * be recognized by hardware for LRO, GRO, and RSC offloads.  The main
- * motivation of doing this is to only perform one pull for IPv4 TCP
- * packets so that we can do basic things like calculating the gso_size
- * based on the average data per packet.
- **/
-static unsigned int ixgbe_get_headlen(unsigned char *data,
-				      unsigned int max_len)
-{
-	union {
-		unsigned char *network;
-		/* l2 headers */
-		struct ethhdr *eth;
-		struct vlan_hdr *vlan;
-		/* l3 headers */
-		struct iphdr *ipv4;
-		struct ipv6hdr *ipv6;
-	} hdr;
-	__be16 protocol;
-	u8 nexthdr = 0;	/* default to not TCP */
-	u8 hlen;
-
-	/* this should never happen, but better safe than sorry */
-	if (max_len < ETH_HLEN)
-		return max_len;
-
-	/* initialize network frame pointer */
-	hdr.network = data;
-
-	/* set first protocol and move network header forward */
-	protocol = hdr.eth->h_proto;
-	hdr.network += ETH_HLEN;
-
-	/* handle any vlan tag if present */
-	if (protocol == htons(ETH_P_8021Q)) {
-		if ((hdr.network - data) > (max_len - VLAN_HLEN))
-			return max_len;
-
-		protocol = hdr.vlan->h_vlan_encapsulated_proto;
-		hdr.network += VLAN_HLEN;
-	}
-
-	/* handle L3 protocols */
-	if (protocol == htons(ETH_P_IP)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct iphdr)))
-			return max_len;
-
-		/* access ihl as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[0] & 0x0F) << 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct iphdr))
-			return hdr.network - data;
-
-		/* record next protocol if header is present */
-		if (!(hdr.ipv4->frag_off & htons(IP_OFFSET)))
-			nexthdr = hdr.ipv4->protocol;
-	} else if (protocol == htons(ETH_P_IPV6)) {
-		if ((hdr.network - data) > (max_len - sizeof(struct ipv6hdr)))
-			return max_len;
-
-		/* record next protocol */
-		nexthdr = hdr.ipv6->nexthdr;
-		hlen = sizeof(struct ipv6hdr);
-#ifdef IXGBE_FCOE
-	} else if (protocol == htons(ETH_P_FCOE)) {
-		if ((hdr.network - data) > (max_len - FCOE_HEADER_LEN))
-			return max_len;
-		hlen = FCOE_HEADER_LEN;
-#endif
-	} else {
-		return hdr.network - data;
-	}
-
-	/* relocate pointer to start of L4 header */
-	hdr.network += hlen;
-
-	/* finally sort out TCP/UDP */
-	if (nexthdr == IPPROTO_TCP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct tcphdr)))
-			return max_len;
-
-		/* access doff as a u8 to avoid unaligned access on ia64 */
-		hlen = (hdr.network[12] & 0xF0) >> 2;
-
-		/* verify hlen meets minimum size requirements */
-		if (hlen < sizeof(struct tcphdr))
-			return hdr.network - data;
-
-		hdr.network += hlen;
-	} else if (nexthdr == IPPROTO_UDP) {
-		if ((hdr.network - data) > (max_len - sizeof(struct udphdr)))
-			return max_len;
-
-		hdr.network += sizeof(struct udphdr);
-	}
-
-	/*
-	 * If everything has gone correctly hdr.network should be the
-	 * data section of the packet and will be the end of the header.
-	 * If not then it probably represents the end of the last recognized
-	 * header.
-	 */
-	if ((hdr.network - data) < max_len)
-		return hdr.network - data;
-	else
-		return max_len;
-}
-
 static void ixgbe_set_rsc_gso_size(struct ixgbe_ring *ring,
 				   struct sk_buff *skb)
 {
@@ -1793,7 +1679,7 @@ static void ixgbe_pull_tail(struct ixgbe_ring *rx_ring,
 	 * we need the header to contain the greater of either ETH_HLEN or
 	 * 60 bytes if the skb->len is less than 60 for skb_pad.
 	 */
-	pull_len = ixgbe_get_headlen(va, IXGBE_RX_HDR_SIZE);
+	pull_len = eth_get_headlen(va, IXGBE_RX_HDR_SIZE);
 
 	/* align pull length to size of long to optimize memcpy performance */
 	skb_copy_to_linear_data(skb, va, ALIGN(pull_len, sizeof(long)));

Re: [PATCH net-next v2 1/3] net: Add function for parsing the header length out of linear ethernet frames

From: Alexei Starovoitov <hidden>
Date: 2014-09-05 23:39:11

On Fri, Sep 05, 2014 at 07:20:26PM -0400, Alexander Duyck wrote:
This patch updates some of the flow_dissector api so that it can be used to
parse the length of ethernet buffers stored in fragments.  Most of the
changes needed were to __skb_get_poff as it needed to be updated to support
sending a linear buffer instead of a skb.

I have split __skb_get_poff into two functions, the first is skb_get_poff
and it retains the functionality of the original __skb_get_poff.  The other
function is __skb_get_poff which now works much like __skb_flow_dissect in
relation to skb_flow_dissect in that it provides the same functionality but
works with just a data buffer and hlen instead of needing an skb.

Signed-off-by: Alexander Duyck <redacted>
---
 include/linux/etherdevice.h |    1 +
 include/linux/skbuff.h      |    4 +++-
 include/net/flow_keys.h     |    2 ++
 net/core/filter.c           |    2 +-
 net/core/flow_dissector.c   |   46 ++++++++++++++++++++++++++++++-------------
 net/ethernet/eth.c          |   27 +++++++++++++++++++++++++
 6 files changed, 66 insertions(+), 16 deletions(-)
names and bpf related bits look good to me
Acked-by: Alexei Starovoitov <redacted>

Re: [PATCH net-next v2 0/3] Drop get_headlen functions in favor of generic function

From: David Miller <davem@davemloft.net>
Date: 2014-09-06 00:47:31

From: Alexander Duyck <redacted>
Date: Fri, 05 Sep 2014 19:20:12 -0400
This series replaces the igb_get_headlen and ixgbe_get_headlen functions
with a generic function named eth_get_headlen.

I have done some performance testing on ixgbe with 258 byte frames since
the calls are only used on frames larger than 256 bytes and have seen no
significant difference in CPU utilization.

v2: renamed __skb_get_poff to skb_get_poff
    renamed ___skb_get_poff to __skb_get_poff
Nice work, series applied, thanks Alex.
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