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net: dsa: remove the "dsa_to_port in a loop" antipattern from the core
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Ever since Vivien's conversion of the ds->ports array into a dst->ports
list, and the introduction of dsa_to_port, iterations through the ports
of a switch became quadratic whenever dsa_to_port was needed.

dsa_to_port can either be called directly, or indirectly through the
dsa_is_{user,cpu,dsa,unused}_port helpers.

Use the newly introduced dsa_switch_for_each_port() iteration macro
that works with the iterator variable being a struct dsa_port *dp
directly, and not an int i. It is an expensive variable to go from i to
dp, but cheap to go from dp to i.

This macro iterates through the entire ds->dst->ports list and filters
by the ports belonging just to the switch provided as argument.

Signed-off-by: Vladimir Oltean <[email protected]>
Reviewed-by: Florian Fainelli <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@vladimiroltean @davem330
vladimiroltean authored and davem330 committed Oct 21, 2021
1 parent 82b3189 commit d0004a0
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Showing 6 changed files with 45 additions and 56 deletions.
7 changes: 3 additions & 4 deletions include/net/dsa.h
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Original file line number Diff line number Diff line change
Expand Up @@ -504,12 +504,11 @@ static inline bool dsa_is_user_port(struct dsa_switch *ds, int p)

static inline u32 dsa_user_ports(struct dsa_switch *ds)
{
struct dsa_port *dp;
u32 mask = 0;
int p;

for (p = 0; p < ds->num_ports; p++)
if (dsa_is_user_port(ds, p))
mask |= BIT(p);
dsa_switch_for_each_user_port(dp, ds)
mask |= BIT(dp->index);

return mask;
}
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22 changes: 11 additions & 11 deletions net/dsa/dsa.c
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Original file line number Diff line number Diff line change
Expand Up @@ -280,23 +280,22 @@ static int dsa_switch_rcv(struct sk_buff *skb, struct net_device *dev,
}

#ifdef CONFIG_PM_SLEEP
static bool dsa_is_port_initialized(struct dsa_switch *ds, int p)
static bool dsa_port_is_initialized(const struct dsa_port *dp)
{
const struct dsa_port *dp = dsa_to_port(ds, p);

return dp->type == DSA_PORT_TYPE_USER && dp->slave;
}

int dsa_switch_suspend(struct dsa_switch *ds)
{
int i, ret = 0;
struct dsa_port *dp;
int ret = 0;

/* Suspend slave network devices */
for (i = 0; i < ds->num_ports; i++) {
if (!dsa_is_port_initialized(ds, i))
dsa_switch_for_each_port(dp, ds) {
if (!dsa_port_is_initialized(dp))
continue;

ret = dsa_slave_suspend(dsa_to_port(ds, i)->slave);
ret = dsa_slave_suspend(dp->slave);
if (ret)
return ret;
}
Expand All @@ -310,7 +309,8 @@ EXPORT_SYMBOL_GPL(dsa_switch_suspend);

int dsa_switch_resume(struct dsa_switch *ds)
{
int i, ret = 0;
struct dsa_port *dp;
int ret = 0;

if (ds->ops->resume)
ret = ds->ops->resume(ds);
Expand All @@ -319,11 +319,11 @@ int dsa_switch_resume(struct dsa_switch *ds)
return ret;

/* Resume slave network devices */
for (i = 0; i < ds->num_ports; i++) {
if (!dsa_is_port_initialized(ds, i))
dsa_switch_for_each_port(dp, ds) {
if (!dsa_port_is_initialized(dp))
continue;

ret = dsa_slave_resume(dsa_to_port(ds, i)->slave);
ret = dsa_slave_resume(dp->slave);
if (ret)
return ret;
}
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13 changes: 6 additions & 7 deletions net/dsa/dsa2.c
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Original file line number Diff line number Diff line change
Expand Up @@ -802,17 +802,16 @@ static int dsa_switch_setup_tag_protocol(struct dsa_switch *ds)
{
const struct dsa_device_ops *tag_ops = ds->dst->tag_ops;
struct dsa_switch_tree *dst = ds->dst;
int port, err;
struct dsa_port *cpu_dp;
int err;

if (tag_ops->proto == dst->default_proto)
return 0;

for (port = 0; port < ds->num_ports; port++) {
if (!dsa_is_cpu_port(ds, port))
continue;

dsa_switch_for_each_cpu_port(cpu_dp, ds) {
rtnl_lock();
err = ds->ops->change_tag_protocol(ds, port, tag_ops->proto);
err = ds->ops->change_tag_protocol(ds, cpu_dp->index,
tag_ops->proto);
rtnl_unlock();
if (err) {
dev_err(ds->dev, "Unable to use tag protocol \"%s\": %pe\n",
Expand Down Expand Up @@ -1150,7 +1149,7 @@ int dsa_tree_change_tag_proto(struct dsa_switch_tree *dst,
goto out_unlock;

list_for_each_entry(dp, &dst->ports, list) {
if (!dsa_is_user_port(dp->ds, dp->index))
if (!dsa_port_is_user(dp))
continue;

if (dp->slave->flags & IFF_UP)
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17 changes: 7 additions & 10 deletions net/dsa/port.c
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Original file line number Diff line number Diff line change
Expand Up @@ -515,7 +515,8 @@ static bool dsa_port_can_apply_vlan_filtering(struct dsa_port *dp,
struct netlink_ext_ack *extack)
{
struct dsa_switch *ds = dp->ds;
int err, i;
struct dsa_port *other_dp;
int err;

/* VLAN awareness was off, so the question is "can we turn it on".
* We may have had 8021q uppers, those need to go. Make sure we don't
Expand Down Expand Up @@ -557,10 +558,10 @@ static bool dsa_port_can_apply_vlan_filtering(struct dsa_port *dp,
* different ports of the same switch device and one of them has a
* different setting than what is being requested.
*/
for (i = 0; i < ds->num_ports; i++) {
dsa_switch_for_each_port(other_dp, ds) {
struct net_device *other_bridge;

other_bridge = dsa_to_port(ds, i)->bridge_dev;
other_bridge = other_dp->bridge_dev;
if (!other_bridge)
continue;
/* If it's the same bridge, it also has same
Expand Down Expand Up @@ -607,20 +608,16 @@ int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
return err;

if (ds->vlan_filtering_is_global) {
int port;
struct dsa_port *other_dp;

ds->vlan_filtering = vlan_filtering;

for (port = 0; port < ds->num_ports; port++) {
struct net_device *slave;

if (!dsa_is_user_port(ds, port))
continue;
dsa_switch_for_each_user_port(other_dp, ds) {
struct net_device *slave = dp->slave;

/* We might be called in the unbind path, so not
* all slave devices might still be registered.
*/
slave = dsa_to_port(ds, port)->slave;
if (!slave)
continue;

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2 changes: 1 addition & 1 deletion net/dsa/slave.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2368,7 +2368,7 @@ static int dsa_slave_netdevice_event(struct notifier_block *nb,
dst = cpu_dp->ds->dst;

list_for_each_entry(dp, &dst->ports, list) {
if (!dsa_is_user_port(dp->ds, dp->index))
if (!dsa_port_is_user(dp))
continue;

list_add(&dp->slave->close_list, &close_list);
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40 changes: 17 additions & 23 deletions net/dsa/switch.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,14 +17,11 @@
static unsigned int dsa_switch_fastest_ageing_time(struct dsa_switch *ds,
unsigned int ageing_time)
{
int i;

for (i = 0; i < ds->num_ports; ++i) {
struct dsa_port *dp = dsa_to_port(ds, i);
struct dsa_port *dp;

dsa_switch_for_each_port(dp, ds)
if (dp->ageing_time && dp->ageing_time < ageing_time)
ageing_time = dp->ageing_time;
}

return ageing_time;
}
Expand Down Expand Up @@ -120,7 +117,8 @@ static int dsa_switch_bridge_leave(struct dsa_switch *ds,
struct netlink_ext_ack extack = {0};
bool change_vlan_filtering = false;
bool vlan_filtering;
int err, port;
struct dsa_port *dp;
int err;

if (dst->index == info->tree_index && ds->index == info->sw_index &&
ds->ops->port_bridge_leave)
Expand Down Expand Up @@ -150,10 +148,10 @@ static int dsa_switch_bridge_leave(struct dsa_switch *ds,
* VLAN-aware bridge.
*/
if (change_vlan_filtering && ds->vlan_filtering_is_global) {
for (port = 0; port < ds->num_ports; port++) {
dsa_switch_for_each_port(dp, ds) {
struct net_device *bridge_dev;

bridge_dev = dsa_to_port(ds, port)->bridge_dev;
bridge_dev = dp->bridge_dev;

if (bridge_dev && br_vlan_enabled(bridge_dev)) {
change_vlan_filtering = false;
Expand Down Expand Up @@ -579,38 +577,34 @@ static int dsa_switch_change_tag_proto(struct dsa_switch *ds,
struct dsa_notifier_tag_proto_info *info)
{
const struct dsa_device_ops *tag_ops = info->tag_ops;
int port, err;
struct dsa_port *dp, *cpu_dp;
int err;

if (!ds->ops->change_tag_protocol)
return -EOPNOTSUPP;

ASSERT_RTNL();

for (port = 0; port < ds->num_ports; port++) {
if (!dsa_is_cpu_port(ds, port))
continue;

err = ds->ops->change_tag_protocol(ds, port, tag_ops->proto);
dsa_switch_for_each_cpu_port(cpu_dp, ds) {
err = ds->ops->change_tag_protocol(ds, cpu_dp->index,
tag_ops->proto);
if (err)
return err;

dsa_port_set_tag_protocol(dsa_to_port(ds, port), tag_ops);
dsa_port_set_tag_protocol(cpu_dp, tag_ops);
}

/* Now that changing the tag protocol can no longer fail, let's update
* the remaining bits which are "duplicated for faster access", and the
* bits that depend on the tagger, such as the MTU.
*/
for (port = 0; port < ds->num_ports; port++) {
if (dsa_is_user_port(ds, port)) {
struct net_device *slave;
dsa_switch_for_each_user_port(dp, ds) {
struct net_device *slave = dp->slave;

slave = dsa_to_port(ds, port)->slave;
dsa_slave_setup_tagger(slave);
dsa_slave_setup_tagger(slave);

/* rtnl_mutex is held in dsa_tree_change_tag_proto */
dsa_slave_change_mtu(slave, slave->mtu);
}
/* rtnl_mutex is held in dsa_tree_change_tag_proto */
dsa_slave_change_mtu(slave, slave->mtu);
}

return 0;
Expand Down

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