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charset="utf-8" tun.c changed from skb_get_hash() to __skb_get_hash_symmetric() on commit feec084a7cf4 ("tun: use symmetric hash"), which exposes an overhead for OVS datapath, where ovs_dp_process_packet() has to calculate the hash again because __skb_get_hash_symmetric() does not retain the hash that it calculates. Introduce skb_get_hash_symmetric(), which will get and save the hash in one go, so that calcuation work does not go to waste, and plumb it into tun.c. Fixes: feec084a7cf4 ("tun: use symmetric hash") Signed-off-by: Jon Kohler CC: Jason Wang CC: David S. Miller --- drivers/net/tun.c | 8 ++++---- include/linux/skbuff.h | 1 + net/core/flow_dissector.c | 29 +++++++++++++++++++++++++++++ 3 files changed, 34 insertions(+), 4 deletions(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index d75456adc62a..27e9be434593 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -528,7 +528,7 @@ static u16 tun_automq_select_queue(struct tun_struct *t= un, struct sk_buff *skb) numqueues =3D READ_ONCE(tun->numqueues); - txq =3D __skb_get_hash_symmetric(skb); + txq =3D skb_get_hash_symmetric(skb); e =3D tun_flow_find(&tun->flows[tun_hashfn(txq)], txq); if (e) { tun_flow_save_rps_rxhash(e, txq); @@ -1046,7 +1046,7 @@ static void tun_automq_xmit(struct tun_struct *tun, s= truct sk_buff *skb) struct tun_flow_entry *e; __u32 rxhash; - rxhash =3D __skb_get_hash_symmetric(skb); + rxhash =3D skb_get_hash_symmetric(skb); e =3D tun_flow_find(&tun->flows[tun_hashfn(rxhash)], rxhash); if (e) tun_flow_save_rps_rxhash(e, rxhash); @@ -1933,7 +1933,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, s= truct tun_file *tfile, */ if (!rcu_access_pointer(tun->steering_prog) && tun->numqueues > 1 && !tfile->detached) - rxhash =3D __skb_get_hash_symmetric(skb); + rxhash =3D skb_get_hash_symmetric(skb); rcu_read_lock(); if (unlikely(!(tun->dev->flags & IFF_UP))) { @@ -2515,7 +2515,7 @@ static int tun_xdp_one(struct tun_struct *tun, if (!rcu_dereference(tun->steering_prog) && tun->numqueues > 1 && !tfile->detached) - rxhash =3D __skb_get_hash_symmetric(skb); + rxhash =3D skb_get_hash_symmetric(skb); if (tfile->napi_enabled) { queue =3D &tfile->sk.sk_write_queue; diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 0b40417457cd..8112b1ab5735 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1474,6 +1474,7 @@ __skb_set_sw_hash(struct sk_buff *skb, __u32 hash, bo= ol is_l4) void __skb_get_hash(struct sk_buff *skb); u32 __skb_get_hash_symmetric(const struct sk_buff *skb); +u32 skb_get_hash_symmetric(struct sk_buff *skb); u32 skb_get_poff(const struct sk_buff *skb); u32 __skb_get_poff(const struct sk_buff *skb, const void *data, const struct flow_keys_basic *keys, int hlen); diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 25fb0bbc310f..d8c0e804bbfe 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -1747,6 +1747,35 @@ u32 __skb_get_hash_symmetric(const struct sk_buff *s= kb) } EXPORT_SYMBOL_GPL(__skb_get_hash_symmetric); +/** + * skb_get_hash_symmetric: calculate and set a flow hash in @skb, using + * flow_keys_dissector_symmetric. + * @skb: sk_buff to calculate flow hash from + * + * This function is similar to __skb_get_hash_symmetric except that it + * retains the hash within the skb, such that it can be reused without + * being recalculated later. + */ +u32 skb_get_hash_symmetric(struct sk_buff *skb) +{ + struct flow_keys keys; + u32 hash; + + __flow_hash_secret_init(); + + memset(&keys, 0, sizeof(keys)); + __skb_flow_dissect(NULL, skb, &flow_keys_dissector_symmetric, + &keys, NULL, 0, 0, 0, + FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL); + + hash =3D __flow_hash_from_keys(&keys, &hashrnd); + + __skb_set_sw_hash(skb, hash, flow_keys_have_l4(&keys)); + + return hash; +} +EXPORT_SYMBOL_GPL(skb_get_hash_symmetric); + /** * __skb_get_hash: calculate a flow hash * @skb: sk_buff to calculate flow hash from -- 2.30.1 (Apple Git-130)