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sched: act: ife: update parameters via rcu handling
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This patch changes the parameter updating via RCU and not protected by a
spinlock anymore. This reduce the time that the spinlock is being held.

Signed-off-by: Alexander Aring <aring@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Alexander Aring authored and David S. Miller committed Oct 13, 2017
1 parent ced273e commit aa9fd9a
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Showing 2 changed files with 67 additions and 30 deletions.
10 changes: 8 additions & 2 deletions include/net/tc_act/tc_ife.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -6,12 +6,18 @@
#include <linux/rtnetlink.h>
#include <linux/module.h>

struct tcf_ife_info {
struct tc_action common;
struct tcf_ife_params {
u8 eth_dst[ETH_ALEN];
u8 eth_src[ETH_ALEN];
u16 eth_type;
u16 flags;

struct rcu_head rcu;
};

struct tcf_ife_info {
struct tc_action common;
struct tcf_ife_params __rcu *params;
/* list of metaids allowed */
struct list_head metalist;
};
Expand Down
87 changes: 59 additions & 28 deletions net/sched/act_ife.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -406,10 +406,14 @@ static void _tcf_ife_cleanup(struct tc_action *a, int bind)
static void tcf_ife_cleanup(struct tc_action *a, int bind)
{
struct tcf_ife_info *ife = to_ife(a);
struct tcf_ife_params *p;

spin_lock_bh(&ife->tcf_lock);
_tcf_ife_cleanup(a, bind);
spin_unlock_bh(&ife->tcf_lock);

p = rcu_dereference_protected(ife->params, 1);
kfree_rcu(p, rcu);
}

/* under ife->tcf_lock for existing action */
Expand Down Expand Up @@ -446,6 +450,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
struct tc_action_net *tn = net_generic(net, ife_net_id);
struct nlattr *tb[TCA_IFE_MAX + 1];
struct nlattr *tb2[IFE_META_MAX + 1];
struct tcf_ife_params *p, *p_old;
struct tcf_ife_info *ife;
u16 ife_type = ETH_P_IFE;
struct tc_ife *parm;
Expand All @@ -471,24 +476,34 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
if (parm->flags & ~IFE_ENCODE)
return -EINVAL;

p = kzalloc(sizeof(*p), GFP_KERNEL);
if (!p)
return -ENOMEM;

exists = tcf_idr_check(tn, parm->index, a, bind);
if (exists && bind)
if (exists && bind) {
kfree(p);
return 0;
}

if (!exists) {
ret = tcf_idr_create(tn, parm->index, est, a, &act_ife_ops,
bind, true);
if (ret)
if (ret) {
kfree(p);
return ret;
}
ret = ACT_P_CREATED;
} else {
tcf_idr_release(*a, bind);
if (!ovr)
if (!ovr) {
kfree(p);
return -EEXIST;
}
}

ife = to_ife(*a);
ife->flags = parm->flags;
p->flags = parm->flags;

if (parm->flags & IFE_ENCODE) {
if (tb[TCA_IFE_TYPE])
Expand All @@ -499,24 +514,25 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
saddr = nla_data(tb[TCA_IFE_SMAC]);
}

if (exists)
spin_lock_bh(&ife->tcf_lock);
ife->tcf_action = parm->action;

if (parm->flags & IFE_ENCODE) {
if (daddr)
ether_addr_copy(ife->eth_dst, daddr);
ether_addr_copy(p->eth_dst, daddr);
else
eth_zero_addr(ife->eth_dst);
eth_zero_addr(p->eth_dst);

if (saddr)
ether_addr_copy(ife->eth_src, saddr);
ether_addr_copy(p->eth_src, saddr);
else
eth_zero_addr(ife->eth_src);
eth_zero_addr(p->eth_src);

ife->eth_type = ife_type;
p->eth_type = ife_type;
}

if (exists)
spin_lock_bh(&ife->tcf_lock);

if (ret == ACT_P_CREATED)
INIT_LIST_HEAD(&ife->metalist);

Expand All @@ -532,6 +548,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,

if (exists)
spin_unlock_bh(&ife->tcf_lock);
kfree(p);
return err;
}

Expand All @@ -552,13 +569,19 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,

if (exists)
spin_unlock_bh(&ife->tcf_lock);
kfree(p);
return err;
}
}

if (exists)
spin_unlock_bh(&ife->tcf_lock);

p_old = rtnl_dereference(ife->params);
rcu_assign_pointer(ife->params, p);
if (p_old)
kfree_rcu(p_old, rcu);

if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);

Expand All @@ -570,12 +593,13 @@ static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
{
unsigned char *b = skb_tail_pointer(skb);
struct tcf_ife_info *ife = to_ife(a);
struct tcf_ife_params *p = rtnl_dereference(ife->params);
struct tc_ife opt = {
.index = ife->tcf_index,
.refcnt = ife->tcf_refcnt - ref,
.bindcnt = ife->tcf_bindcnt - bind,
.action = ife->tcf_action,
.flags = ife->flags,
.flags = p->flags,
};
struct tcf_t t;

Expand All @@ -586,17 +610,17 @@ static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
if (nla_put_64bit(skb, TCA_IFE_TM, sizeof(t), &t, TCA_IFE_PAD))
goto nla_put_failure;

if (!is_zero_ether_addr(ife->eth_dst)) {
if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, ife->eth_dst))
if (!is_zero_ether_addr(p->eth_dst)) {
if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, p->eth_dst))
goto nla_put_failure;
}

if (!is_zero_ether_addr(ife->eth_src)) {
if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, ife->eth_src))
if (!is_zero_ether_addr(p->eth_src)) {
if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, p->eth_src))
goto nla_put_failure;
}

if (nla_put(skb, TCA_IFE_TYPE, 2, &ife->eth_type))
if (nla_put(skb, TCA_IFE_TYPE, 2, &p->eth_type))
goto nla_put_failure;

if (dump_metalist(skb, ife)) {
Expand Down Expand Up @@ -698,7 +722,7 @@ static int ife_get_sz(struct sk_buff *skb, struct tcf_ife_info *ife)
}

static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
struct tcf_result *res, struct tcf_ife_params *p)
{
struct tcf_ife_info *ife = to_ife(a);
int action = ife->tcf_action;
Expand Down Expand Up @@ -762,29 +786,36 @@ static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
}
skboff += err;
}
spin_unlock(&ife->tcf_lock);
oethh = (struct ethhdr *)skb->data;

if (!is_zero_ether_addr(ife->eth_src))
ether_addr_copy(oethh->h_source, ife->eth_src);
if (!is_zero_ether_addr(ife->eth_dst))
ether_addr_copy(oethh->h_dest, ife->eth_dst);
oethh->h_proto = htons(ife->eth_type);
if (!is_zero_ether_addr(p->eth_src))
ether_addr_copy(oethh->h_source, p->eth_src);
if (!is_zero_ether_addr(p->eth_dst))
ether_addr_copy(oethh->h_dest, p->eth_dst);
oethh->h_proto = htons(p->eth_type);

if (skb_at_tc_ingress(skb))
skb_pull(skb, skb->dev->hard_header_len);

spin_unlock(&ife->tcf_lock);

return action;
}

static int tcf_ife_act(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct tcf_ife_info *ife = to_ife(a);

if (ife->flags & IFE_ENCODE)
return tcf_ife_encode(skb, a, res);
struct tcf_ife_params *p;
int ret;

rcu_read_lock();
p = rcu_dereference(ife->params);
if (p->flags & IFE_ENCODE) {
ret = tcf_ife_encode(skb, a, res, p);
rcu_read_unlock();
return ret;
}
rcu_read_unlock();

return tcf_ife_decode(skb, a, res);
}
Expand Down

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