From 8fc54f68919298ff9689d980efb495707ef43f30 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Sat, 23 Aug 2014 20:58:54 +0200 Subject: [PATCH] net: use reciprocal_scale() helper Replace open codings of (((u64) * ) >> 32) with reciprocal_scale(). Signed-off-by: Daniel Borkmann Cc: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/core/dev.c | 3 +-- net/core/flow_dissector.c | 7 +++---- net/ipv4/inet_hashtables.c | 2 +- net/ipv4/netfilter/ipt_CLUSTERIP.c | 2 +- net/ipv4/udp.c | 6 +++--- net/ipv6/inet6_hashtables.c | 2 +- net/ipv6/udp.c | 4 ++-- net/netfilter/nf_conntrack_core.c | 2 +- net/netfilter/nf_conntrack_expect.c | 3 ++- net/netfilter/nf_nat_core.c | 5 +++-- net/netfilter/xt_HMARK.c | 2 +- net/netfilter/xt_cluster.c | 3 ++- net/netfilter/xt_hashlimit.c | 2 +- net/sched/sch_fq_codel.c | 3 ++- 14 files changed, 24 insertions(+), 22 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index b65a5051361f..1421dad4cb29 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3124,8 +3124,7 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb, } if (map) { - tcpu = map->cpus[((u64) hash * map->len) >> 32]; - + tcpu = map->cpus[reciprocal_scale(hash, map->len)]; if (cpu_online(tcpu)) { cpu = tcpu; goto done; diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c index 660c6492fb78..8ffcc97871c8 100644 --- a/net/core/flow_dissector.c +++ b/net/core/flow_dissector.c @@ -298,7 +298,7 @@ u16 __skb_tx_hash(const struct net_device *dev, struct sk_buff *skb, qcount = dev->tc_to_txq[tc].count; } - return (u16) (((u64)skb_get_hash(skb) * qcount) >> 32) + qoffset; + return (u16) reciprocal_scale(skb_get_hash(skb), qcount) + qoffset; } EXPORT_SYMBOL(__skb_tx_hash); @@ -371,9 +371,8 @@ static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb) if (map->len == 1) queue_index = map->queues[0]; else - queue_index = map->queues[ - ((u64)skb_get_hash(skb) * map->len) >> 32]; - + queue_index = map->queues[reciprocal_scale(skb_get_hash(skb), + map->len)]; if (unlikely(queue_index >= dev->real_num_tx_queues)) queue_index = -1; } diff --git a/net/ipv4/inet_hashtables.c b/net/ipv4/inet_hashtables.c index 43116e8c8e13..9111a4e22155 100644 --- a/net/ipv4/inet_hashtables.c +++ b/net/ipv4/inet_hashtables.c @@ -229,7 +229,7 @@ begin: } } else if (score == hiscore && reuseport) { matches++; - if (((u64)phash * matches) >> 32 == 0) + if (reciprocal_scale(phash, matches) == 0) result = sk; phash = next_pseudo_random32(phash); } diff --git a/net/ipv4/netfilter/ipt_CLUSTERIP.c b/net/ipv4/netfilter/ipt_CLUSTERIP.c index 2510c02c2d21..e90f83a3415b 100644 --- a/net/ipv4/netfilter/ipt_CLUSTERIP.c +++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c @@ -285,7 +285,7 @@ clusterip_hashfn(const struct sk_buff *skb, } /* node numbers are 1..n, not 0..n */ - return (((u64)hashval * config->num_total_nodes) >> 32) + 1; + return reciprocal_scale(hashval, config->num_total_nodes) + 1; } static inline int diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index f57c0e4c2326..32f9571e776b 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -224,7 +224,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum, remaining = (high - low) + 1; rand = prandom_u32(); - first = (((u64)rand * remaining) >> 32) + low; + first = reciprocal_scale(rand, remaining) + low; /* * force rand to be an odd multiple of UDP_HTABLE_SIZE */ @@ -448,7 +448,7 @@ begin: } } else if (score == badness && reuseport) { matches++; - if (((u64)hash * matches) >> 32 == 0) + if (reciprocal_scale(hash, matches) == 0) result = sk; hash = next_pseudo_random32(hash); } @@ -529,7 +529,7 @@ begin: } } else if (score == badness && reuseport) { matches++; - if (((u64)hash * matches) >> 32 == 0) + if (reciprocal_scale(hash, matches) == 0) result = sk; hash = next_pseudo_random32(hash); } diff --git a/net/ipv6/inet6_hashtables.c b/net/ipv6/inet6_hashtables.c index 262e13c02ec2..826019008958 100644 --- a/net/ipv6/inet6_hashtables.c +++ b/net/ipv6/inet6_hashtables.c @@ -198,7 +198,7 @@ begin: } } else if (score == hiscore && reuseport) { matches++; - if (((u64)phash * matches) >> 32 == 0) + if (reciprocal_scale(phash, matches) == 0) result = sk; phash = next_pseudo_random32(phash); } diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 4836af8f582d..25ffe737b975 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -243,7 +243,7 @@ begin: goto exact_match; } else if (score == badness && reuseport) { matches++; - if (((u64)hash * matches) >> 32 == 0) + if (reciprocal_scale(hash, matches) == 0) result = sk; hash = next_pseudo_random32(hash); } @@ -323,7 +323,7 @@ begin: } } else if (score == badness && reuseport) { matches++; - if (((u64)hash * matches) >> 32 == 0) + if (reciprocal_scale(hash, matches) == 0) result = sk; hash = next_pseudo_random32(hash); } diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c index 0b634e7f1652..5016a6929085 100644 --- a/net/netfilter/nf_conntrack_core.c +++ b/net/netfilter/nf_conntrack_core.c @@ -142,7 +142,7 @@ static u32 hash_conntrack_raw(const struct nf_conntrack_tuple *tuple, u16 zone) static u32 __hash_bucket(u32 hash, unsigned int size) { - return ((u64)hash * size) >> 32; + return reciprocal_scale(hash, size); } static u32 hash_bucket(u32 hash, const struct net *net) diff --git a/net/netfilter/nf_conntrack_expect.c b/net/netfilter/nf_conntrack_expect.c index f87e8f68ad45..91a1837acd0e 100644 --- a/net/netfilter/nf_conntrack_expect.c +++ b/net/netfilter/nf_conntrack_expect.c @@ -83,7 +83,8 @@ static unsigned int nf_ct_expect_dst_hash(const struct nf_conntrack_tuple *tuple hash = jhash2(tuple->dst.u3.all, ARRAY_SIZE(tuple->dst.u3.all), (((tuple->dst.protonum ^ tuple->src.l3num) << 16) | (__force __u16)tuple->dst.u.all) ^ nf_conntrack_hash_rnd); - return ((u64)hash * nf_ct_expect_hsize) >> 32; + + return reciprocal_scale(hash, nf_ct_expect_hsize); } struct nf_conntrack_expect * diff --git a/net/netfilter/nf_nat_core.c b/net/netfilter/nf_nat_core.c index 552f97cd9fde..4e0b47831d43 100644 --- a/net/netfilter/nf_nat_core.c +++ b/net/netfilter/nf_nat_core.c @@ -126,7 +126,8 @@ hash_by_src(const struct net *net, u16 zone, /* Original src, to ensure we map it consistently if poss. */ hash = jhash2((u32 *)&tuple->src, sizeof(tuple->src) / sizeof(u32), tuple->dst.protonum ^ zone ^ nf_conntrack_hash_rnd); - return ((u64)hash * net->ct.nat_htable_size) >> 32; + + return reciprocal_scale(hash, net->ct.nat_htable_size); } /* Is this tuple already taken? (not by us) */ @@ -274,7 +275,7 @@ find_best_ips_proto(u16 zone, struct nf_conntrack_tuple *tuple, } var_ipp->all[i] = (__force __u32) - htonl(minip + (((u64)j * dist) >> 32)); + htonl(minip + reciprocal_scale(j, dist)); if (var_ipp->all[i] != range->max_addr.all[i]) full_range = true; diff --git a/net/netfilter/xt_HMARK.c b/net/netfilter/xt_HMARK.c index 73b73f687c58..02afaf48a729 100644 --- a/net/netfilter/xt_HMARK.c +++ b/net/netfilter/xt_HMARK.c @@ -126,7 +126,7 @@ hmark_hash(struct hmark_tuple *t, const struct xt_hmark_info *info) hash = jhash_3words(src, dst, t->uports.v32, info->hashrnd); hash = hash ^ (t->proto & info->proto_mask); - return (((u64)hash * info->hmodulus) >> 32) + info->hoffset; + return reciprocal_scale(hash, info->hmodulus) + info->hoffset; } static void diff --git a/net/netfilter/xt_cluster.c b/net/netfilter/xt_cluster.c index f4af1bfafb1c..96fa26b20b67 100644 --- a/net/netfilter/xt_cluster.c +++ b/net/netfilter/xt_cluster.c @@ -55,7 +55,8 @@ xt_cluster_hash(const struct nf_conn *ct, WARN_ON(1); break; } - return (((u64)hash * info->total_nodes) >> 32); + + return reciprocal_scale(hash, info->total_nodes); } static inline bool diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c index 47dc6836830a..52eb3e03458d 100644 --- a/net/netfilter/xt_hashlimit.c +++ b/net/netfilter/xt_hashlimit.c @@ -135,7 +135,7 @@ hash_dst(const struct xt_hashlimit_htable *ht, const struct dsthash_dst *dst) * give results between [0 and cfg.size-1] and same hash distribution, * but using a multiply, less expensive than a divide */ - return ((u64)hash * ht->cfg.size) >> 32; + return reciprocal_scale(hash, ht->cfg.size); } static struct dsthash_ent * diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c index 063b726bf1f8..cc56c8bb9bed 100644 --- a/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c @@ -77,7 +77,8 @@ static unsigned int fq_codel_hash(const struct fq_codel_sched_data *q, hash = jhash_3words((__force u32)keys.dst, (__force u32)keys.src ^ keys.ip_proto, (__force u32)keys.ports, q->perturbation); - return ((u64)hash * q->flows_cnt) >> 32; + + return reciprocal_scale(hash, q->flows_cnt); } static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch, -- 2.20.1