Merge branch 'reciprocal'

Hannes Frederic Sowa says:

====================
reciprocal_divide update

This patch is on top of aee636c4809fa5 ("bpf: do not use reciprocal
divide") from Eric that sits in net tree. It will not create a merge
conflict, but it depends on this one, so we suggest, if possible, to
merge net into net-next.

We are proposing this change with only small modifications from the
v2 version, namely updating the name of trim to reciprocal_scale
(as commented on by Ben Hutchings and Eric Dumazet, thanks!).

We thought about introducing the reciprocal_divide algorithm in
parallel to the one already used by the kernel but faced organizational
issues, leading us to the conclusion that it is best to just replace
the old one: We could not come up with names for the different
implementations and also with a way to describe the differences to
guide developers which one to choose in which situation. This is
because we cannot specify the correct semantics for the version
which is currently used by the kernel. Altough it seems to not be
causing problems in the kernel, we cannot surely say so in the
case of flex_array for the future. Current usage seems ok, but
future users could run into problems.

Changelog:

v1->v2:
 - changed name to prandom_u32_max in p1
 - changed name to trim in p2
 - reworked code in p3
v2->v3:
 - p1 and p3 stays unchanged, only small update in commit
   message in p3
 - changed name to reciprocal_scale in p2
 - fixed kernel doc format
v3->v4:
 - pseduo -> pseudo (thanks to Tilman Schmidt)
v4->v5:
 - fix pseduo -> pseudo for real now, sorry for the noise
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 31 insertions, 28 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 3220b488dd1e..f100bd958b88 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -79,7 +79,6 @@
 #include <net/pkt_sched.h>
 #include <linux/rculist.h>
 #include <net/flow_keys.h>
-#include <linux/reciprocal_div.h>
 #include "bonding.h"
 #include "bond_3ad.h"
 #include "bond_alb.h"
@@ -3596,8 +3595,9 @@ static void bond_xmit_slave_id(struct bonding *bond, struct sk_buff *skb, int sl
  */
 static u32 bond_rr_gen_slave_id(struct bonding *bond)
 {
-	int packets_per_slave = bond->params.packets_per_slave;
 	u32 slave_id;
+	struct reciprocal_value reciprocal_packets_per_slave;
+	int packets_per_slave = bond->params.packets_per_slave;
 
 	switch (packets_per_slave) {
 	case 0:
@@ -3607,8 +3607,10 @@ static u32 bond_rr_gen_slave_id(struct bonding *bond)
 		slave_id = bond->rr_tx_counter;
 		break;
 	default:
+		reciprocal_packets_per_slave =
+			bond->params.reciprocal_packets_per_slave;
 		slave_id = reciprocal_divide(bond->rr_tx_counter,
-					     packets_per_slave);
+					     reciprocal_packets_per_slave);
 		break;
 	}
 	bond->rr_tx_counter++;
@@ -4343,10 +4345,18 @@ static int bond_check_params(struct bond_params *params)
 	params->resend_igmp = resend_igmp;
 	params->min_links = min_links;
 	params->lp_interval = lp_interval;
-	if (packets_per_slave > 1)
-		params->packets_per_slave = reciprocal_value(packets_per_slave);
-	else
-		params->packets_per_slave = packets_per_slave;
+	params->packets_per_slave = packets_per_slave;
+	if (packets_per_slave > 0) {
+		params->reciprocal_packets_per_slave =
+			reciprocal_value(packets_per_slave);
+	} else {
+		/* reciprocal_packets_per_slave is unused if
+		 * packets_per_slave is 0 or 1, just initialize it
+		 */
+		params->reciprocal_packets_per_slave =
+			(struct reciprocal_value) { 0 };
+	}
+
 	if (primary) {
 		strncpy(params->primary, primary, IFNAMSIZ);
 		params->primary[IFNAMSIZ - 1] = 0;
diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
index 21c648854a8c..e8526552790c 100644
--- a/drivers/net/bonding/bond_netlink.c
+++ b/drivers/net/bonding/bond_netlink.c
@@ -19,7 +19,6 @@
 #include <linux/if_ether.h>
 #include <net/netlink.h>
 #include <net/rtnetlink.h>
-#include <linux/reciprocal_div.h>
 #include "bonding.h"
 
 int bond_get_slave(struct net_device *slave_dev, struct sk_buff *skb)
@@ -452,9 +451,6 @@ static int bond_fill_info(struct sk_buff *skb,
 		goto nla_put_failure;
 
 	packets_per_slave = bond->params.packets_per_slave;
-	if (packets_per_slave > 1)
-		packets_per_slave = reciprocal_value(packets_per_slave);
-
 	if (nla_put_u32(skb, IFLA_BOND_PACKETS_PER_SLAVE,
 			packets_per_slave))
 		goto nla_put_failure;
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index 945a6668da83..85e434886f2e 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -16,7 +16,6 @@
 #include <linux/netdevice.h>
 #include <linux/rwlock.h>
 #include <linux/rcupdate.h>
-#include <linux/reciprocal_div.h>
 #include "bonding.h"
 
 int bond_option_mode_set(struct bonding *bond, int mode)
@@ -671,11 +670,17 @@ int bond_option_packets_per_slave_set(struct bonding *bond,
 		pr_warn("%s: Warning: packets_per_slave has effect only in balance-rr mode\n",
 			bond->dev->name);
 
-	if (packets_per_slave > 1)
-		bond->params.packets_per_slave =
+	bond->params.packets_per_slave = packets_per_slave;
+	if (packets_per_slave > 0) {
+		bond->params.reciprocal_packets_per_slave =
 			reciprocal_value(packets_per_slave);
-	else
-		bond->params.packets_per_slave = packets_per_slave;
+	} else {
+		/* reciprocal_packets_per_slave is unused if
+		 * packets_per_slave is 0 or 1, just initialize it
+		 */
+		bond->params.reciprocal_packets_per_slave =
+			(struct reciprocal_value) { 0 };
+	}
 
 	return 0;
 }
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 011f163c2c67..c083e9a66ece 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -39,7 +39,6 @@
 #include <net/net_namespace.h>
 #include <net/netns/generic.h>
 #include <linux/nsproxy.h>
-#include <linux/reciprocal_div.h>
 
 #include "bonding.h"
 
@@ -1374,10 +1373,6 @@ static ssize_t bonding_show_packets_per_slave(struct device *d,
 {
 	struct bonding *bond = to_bond(d);
 	unsigned int packets_per_slave = bond->params.packets_per_slave;
-
-	if (packets_per_slave > 1)
-		packets_per_slave = reciprocal_value(packets_per_slave);
-
 	return sprintf(buf, "%u\n", packets_per_slave);
 }
 
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 8a935f8f2b3c..0a616c41dc94 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -23,6 +23,8 @@
 #include <linux/netpoll.h>
 #include <linux/inetdevice.h>
 #include <linux/etherdevice.h>
+#include <linux/reciprocal_div.h>
+
 #include "bond_3ad.h"
 #include "bond_alb.h"
 
@@ -171,6 +173,7 @@ struct bond_params {
 	int resend_igmp;
 	int lp_interval;
 	int packets_per_slave;
+	struct reciprocal_value reciprocal_packets_per_slave;
 };
 
 struct bond_parm_tbl {
diff --git a/drivers/net/team/team_mode_random.c b/drivers/net/team/team_mode_random.c
index 7f032e211343..cd2f692b8074 100644
--- a/drivers/net/team/team_mode_random.c
+++ b/drivers/net/team/team_mode_random.c
@@ -13,20 +13,14 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/skbuff.h>
-#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 = prandom_u32_max(team->en_port_count);
 	port = team_get_port_by_index_rcu(team, port_index);
 	if (unlikely(!port))
 		goto drop;