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Date: Tue, 3 Sep 2013 12:26:50 +0200
From: Daniel Borkmann <dborkman@...hat.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org, netfilter-devel@...r.kernel.org
Subject: [PATCH net-next 2/2] net: use reciprocal_divide instead of reimplementing it
Replace these places with reciprocal_divide() inline function instead of
reimplementing it each time, thus it will become easier to read. We do not
need to explicitly include its header as it's pulled in from linux/net.h
anyway.
Signed-off-by: Daniel Borkmann <dborkman@...hat.com>
Cc: netfilter-devel@...r.kernel.org
---
net/core/dev.c | 2 +-
net/core/flow_dissector.c | 5 ++---
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 | 2 +-
net/netfilter/nf_nat_core.c | 4 ++--
net/netfilter/xt_HMARK.c | 2 +-
net/netfilter/xt_NFQUEUE.c | 4 ++--
net/netfilter/xt_cluster.c | 2 +-
net/netfilter/xt_hashlimit.c | 2 +-
net/sched/sch_fq_codel.c | 2 +-
15 files changed, 21 insertions(+), 22 deletions(-)
diff --git a/net/core/dev.c b/net/core/dev.c
index 6fbb0c9..bc7c839 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3040,7 +3040,7 @@ static int get_rps_cpu(struct net_device *dev, struct sk_buff *skb,
}
if (map) {
- tcpu = map->cpus[((u64) skb->rxhash * map->len) >> 32];
+ tcpu = map->cpus[reciprocal_divide(skb->rxhash, map->len)];
if (cpu_online(tcpu)) {
cpu = tcpu;
diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 159737c..59521e0 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -233,7 +233,7 @@ u16 __skb_tx_hash(const struct net_device *dev, const struct sk_buff *skb,
hash = (__force u16) skb->protocol;
hash = jhash_1word(hash, hashrnd);
- return (u16) (((u64) hash * qcount) >> 32) + qoffset;
+ return (u16) reciprocal_divide(hash, qcount) + qoffset;
}
EXPORT_SYMBOL(__skb_tx_hash);
@@ -324,8 +324,7 @@ static inline int get_xps_queue(struct net_device *dev, struct sk_buff *skb)
hash = (__force u16) skb->protocol ^
skb->rxhash;
hash = jhash_1word(hash, hashrnd);
- queue_index = map->queues[
- ((u64)hash * map->len) >> 32];
+ queue_index = map->queues[reciprocal_divide(hash, 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 7bd8983..731dcbf 100644
--- a/net/ipv4/inet_hashtables.c
+++ b/net/ipv4/inet_hashtables.c
@@ -204,7 +204,7 @@ begin:
}
} else if (score == hiscore && reuseport) {
matches++;
- if (((u64)phash * matches) >> 32 == 0)
+ if (reciprocal_divide(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 0b732ef..0fede8b 100644
--- a/net/ipv4/netfilter/ipt_CLUSTERIP.c
+++ b/net/ipv4/netfilter/ipt_CLUSTERIP.c
@@ -273,7 +273,7 @@ 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_divide(hashval, config->num_total_nodes) + 1;
}
static inline int
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 74d2c95..5db0725 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -223,7 +223,7 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
remaining = (high - low) + 1;
rand = net_random();
- first = (((u64)rand * remaining) >> 32) + low;
+ first = reciprocal_divide(rand, remaining) + low;
/*
* force rand to be an odd multiple of UDP_HTABLE_SIZE
*/
@@ -435,7 +435,7 @@ begin:
}
} else if (score == badness && reuseport) {
matches++;
- if (((u64)hash * matches) >> 32 == 0)
+ if (reciprocal_divide(hash, matches) == 0)
result = sk;
hash = next_pseudo_random32(hash);
}
@@ -516,7 +516,7 @@ begin:
}
} else if (score == badness && reuseport) {
matches++;
- if (((u64)hash * matches) >> 32 == 0)
+ if (reciprocal_divide(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 32b4a16..d9d8908 100644
--- a/net/ipv6/inet6_hashtables.c
+++ b/net/ipv6/inet6_hashtables.c
@@ -187,7 +187,7 @@ begin:
}
} else if (score == hiscore && reuseport) {
matches++;
- if (((u64)phash * matches) >> 32 == 0)
+ if (reciprocal_divide(phash, matches) == 0)
result = sk;
phash = next_pseudo_random32(phash);
}
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index f405815..610013a 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -226,7 +226,7 @@ begin:
goto exact_match;
} else if (score == badness && reuseport) {
matches++;
- if (((u64)hash * matches) >> 32 == 0)
+ if (reciprocal_divide(hash, matches) == 0)
result = sk;
hash = next_pseudo_random32(hash);
}
@@ -306,7 +306,7 @@ begin:
}
} else if (score == badness && reuseport) {
matches++;
- if (((u64)hash * matches) >> 32 == 0)
+ if (reciprocal_divide(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 5d892fe..6378441 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -97,7 +97,7 @@ 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_divide(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 4fd1ca9..c0865e6 100644
--- a/net/netfilter/nf_conntrack_expect.c
+++ b/net/netfilter/nf_conntrack_expect.c
@@ -83,7 +83,7 @@ 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_divide(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 6f0f4f7..ce9083e 100644
--- a/net/netfilter/nf_nat_core.c
+++ b/net/netfilter/nf_nat_core.c
@@ -126,7 +126,7 @@ 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_divide(hash, net->ct.nat_htable_size);
}
/* Is this tuple already taken? (not by us) */
@@ -274,7 +274,7 @@ 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_divide(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 73b73f6..3dd05c4 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_divide(hash, info->hmodulus) + info->hoffset;
}
static void
diff --git a/net/netfilter/xt_NFQUEUE.c b/net/netfilter/xt_NFQUEUE.c
index 1e2fae3..88443c1 100644
--- a/net/netfilter/xt_NFQUEUE.c
+++ b/net/netfilter/xt_NFQUEUE.c
@@ -83,10 +83,10 @@ nfqueue_hash(const struct sk_buff *skb, const struct xt_action_param *par)
u32 queue = info->queuenum;
if (par->family == NFPROTO_IPV4)
- queue += ((u64) hash_v4(skb) * info->queues_total) >> 32;
+ queue += reciprocal_divide(hash_v4(skb), info->queues_total);
#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
else if (par->family == NFPROTO_IPV6)
- queue += ((u64) hash_v6(skb) * info->queues_total) >> 32;
+ queue += reciprocal_divide(hash_v6(skb), info->queues_total);
#endif
return queue;
diff --git a/net/netfilter/xt_cluster.c b/net/netfilter/xt_cluster.c
index f4af1bf..845fc16 100644
--- a/net/netfilter/xt_cluster.c
+++ b/net/netfilter/xt_cluster.c
@@ -55,7 +55,7 @@ xt_cluster_hash(const struct nf_conn *ct,
WARN_ON(1);
break;
}
- return (((u64)hash * info->total_nodes) >> 32);
+ return reciprocal_divide(hash, info->total_nodes);
}
static inline bool
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 9ff035c..9af9021 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_divide(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 5578628..4869671 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -77,7 +77,7 @@ 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_divide(hash, q->flows_cnt);
}
static unsigned int fq_codel_classify(struct sk_buff *skb, struct Qdisc *sch,
--
1.7.11.7
--
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