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Date: Tue, 3 Sep 2013 12:26:49 +0200
From: Daniel Borkmann <dborkman@...hat.com>
To: davem@...emloft.net
Cc: netdev@...r.kernel.org
Subject: [PATCH net-next 1/2] net: introduce generic net_random_N helper
We have implemented the same function over and over, so introduce a
generic helper net_random_N() that unifies these implementations.
It internally used net_random() which eventually resolves to
prandom_u32(). Explicit include of reciprocal_div.h is not necessary.
Signed-off-by: Daniel Borkmann <dborkman@...hat.com>
---
drivers/net/team/team_mode_random.c | 7 +------
include/linux/net.h | 7 +++++++
include/net/red.h | 2 +-
net/802/garp.c | 2 +-
net/802/mrp.c | 2 +-
net/packet/af_packet.c | 2 +-
net/sched/sch_choke.c | 8 +-------
7 files changed, 13 insertions(+), 17 deletions(-)
diff --git a/drivers/net/team/team_mode_random.c b/drivers/net/team/team_mode_random.c
index 7f032e2..b2294f8 100644
--- a/drivers/net/team/team_mode_random.c
+++ b/drivers/net/team/team_mode_random.c
@@ -16,17 +16,12 @@
#include <linux/reciprocal_div.h>
#include <linux/if_team.h>
-static u32 random_N(unsigned int N)
-{
- return reciprocal_divide(prandom_u32(), N);
-}
-
static bool rnd_transmit(struct team *team, struct sk_buff *skb)
{
struct team_port *port;
int port_index;
- port_index = random_N(team->en_port_count);
+ port_index = net_random_N(team->en_port_count);
port = team_get_port_by_index_rcu(team, port_index);
if (unlikely(!port))
goto drop;
diff --git a/include/linux/net.h b/include/linux/net.h
index 4f27575..86ffce7 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -24,6 +24,7 @@
#include <linux/fcntl.h> /* For O_CLOEXEC and O_NONBLOCK */
#include <linux/kmemcheck.h>
#include <linux/rcupdate.h>
+#include <linux/reciprocal_div.h>
#include <uapi/linux/net.h>
struct poll_table_struct;
@@ -243,6 +244,12 @@ do { \
#define net_random() prandom_u32()
#define net_srandom(seed) prandom_seed((__force u32)(seed))
+/* deliver a random number between 0 and N - 1 */
+static inline u32 net_random_N(u32 N)
+{
+ return reciprocal_divide(net_random(), N);
+}
+
extern int kernel_sendmsg(struct socket *sock, struct msghdr *msg,
struct kvec *vec, size_t num, size_t len);
extern int kernel_recvmsg(struct socket *sock, struct msghdr *msg,
diff --git a/include/net/red.h b/include/net/red.h
index ef46058..b17ed60 100644
--- a/include/net/red.h
+++ b/include/net/red.h
@@ -303,7 +303,7 @@ static inline unsigned long red_calc_qavg(const struct red_parms *p,
static inline u32 red_random(const struct red_parms *p)
{
- return reciprocal_divide(net_random(), p->max_P_reciprocal);
+ return net_random_N(p->max_P_reciprocal);
}
static inline int red_mark_probability(const struct red_parms *p,
diff --git a/net/802/garp.c b/net/802/garp.c
index 5d9630a..c6fe7ca 100644
--- a/net/802/garp.c
+++ b/net/802/garp.c
@@ -397,7 +397,7 @@ static void garp_join_timer_arm(struct garp_applicant *app)
{
unsigned long delay;
- delay = (u64)msecs_to_jiffies(garp_join_time) * net_random() >> 32;
+ delay = net_random_N(msecs_to_jiffies(garp_join_time));
mod_timer(&app->join_timer, jiffies + delay);
}
diff --git a/net/802/mrp.c b/net/802/mrp.c
index 1eb05d8..7338a7c 100644
--- a/net/802/mrp.c
+++ b/net/802/mrp.c
@@ -578,7 +578,7 @@ static void mrp_join_timer_arm(struct mrp_applicant *app)
{
unsigned long delay;
- delay = (u64)msecs_to_jiffies(mrp_join_time) * net_random() >> 32;
+ delay = net_random_N(msecs_to_jiffies(mrp_join_time));
mod_timer(&app->join_timer, jiffies + delay);
}
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 2e8286b..7ac669e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1162,7 +1162,7 @@ static unsigned int fanout_demux_rnd(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int num)
{
- return reciprocal_divide(prandom_u32(), num);
+ return net_random_N(num);
}
static unsigned int fanout_demux_rollover(struct packet_fanout *f,
diff --git a/net/sched/sch_choke.c b/net/sched/sch_choke.c
index ef53ab8..e19b20be 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -77,12 +77,6 @@ struct choke_sched_data {
struct sk_buff **tab;
};
-/* deliver a random number between 0 and N - 1 */
-static u32 random_N(unsigned int N)
-{
- return reciprocal_divide(prandom_u32(), N);
-}
-
/* number of elements in queue including holes */
static unsigned int choke_len(const struct choke_sched_data *q)
{
@@ -233,7 +227,7 @@ static struct sk_buff *choke_peek_random(const struct choke_sched_data *q,
int retrys = 3;
do {
- *pidx = (q->head + random_N(choke_len(q))) & q->tab_mask;
+ *pidx = (q->head + net_random_N(choke_len(q))) & q->tab_mask;
skb = q->tab[*pidx];
if (skb)
return skb;
--
1.7.11.7
--
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