net: Only do flow_dissector hash computation once per packet
Add sw_hash flag to skbuff to indicate that skb->hash was computed
from flow_dissector. This flag is checked in skb_get_hash to avoid
repeatedly trying to compute the hash (ie. in the case that no L4 hash
can be computed).
Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b297af7..890fb33 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -455,6 +455,7 @@
* @ooo_okay: allow the mapping of a socket to a queue to be changed
* @l4_hash: indicate hash is a canonical 4-tuple hash over transport
* ports.
+ * @sw_hash: indicates hash was computed in software stack
* @wifi_acked_valid: wifi_acked was set
* @wifi_acked: whether frame was acked on wifi or not
* @no_fcs: Request NIC to treat last 4 bytes as Ethernet FCS
@@ -562,6 +563,7 @@
__u8 pfmemalloc:1;
__u8 ooo_okay:1;
__u8 l4_hash:1;
+ __u8 sw_hash:1;
__u8 wifi_acked_valid:1;
__u8 wifi_acked:1;
__u8 no_fcs:1;
@@ -575,7 +577,7 @@
__u8 encap_hdr_csum:1;
__u8 csum_valid:1;
__u8 csum_complete_sw:1;
- /* 3/5 bit hole (depending on ndisc_nodetype presence) */
+ /* 2/4 bit hole (depending on ndisc_nodetype presence) */
kmemcheck_bitfield_end(flags2);
#if defined CONFIG_NET_DMA || defined CONFIG_NET_RX_BUSY_POLL
@@ -830,13 +832,14 @@
skb_set_hash(struct sk_buff *skb, __u32 hash, enum pkt_hash_types type)
{
skb->l4_hash = (type == PKT_HASH_TYPE_L4);
+ skb->sw_hash = 0;
skb->hash = hash;
}
void __skb_get_hash(struct sk_buff *skb);
static inline __u32 skb_get_hash(struct sk_buff *skb)
{
- if (!skb->l4_hash)
+ if (!skb->l4_hash && !skb->sw_hash)
__skb_get_hash(skb);
return skb->hash;
@@ -850,6 +853,7 @@
static inline void skb_clear_hash(struct sk_buff *skb)
{
skb->hash = 0;
+ skb->sw_hash = 0;
skb->l4_hash = 0;
}
@@ -862,6 +866,7 @@
static inline void skb_copy_hash(struct sk_buff *to, const struct sk_buff *from)
{
to->hash = from->hash;
+ to->sw_hash = from->sw_hash;
to->l4_hash = from->l4_hash;
};