lisa/android_kernel_xiaomi_sm8350
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

net: sched: act_skbedit: remove dependency on rtnl lock

Browse Source 
According to the new locking rule, we have to take tcf_lock for both
->init() and ->dump(), as RTNL will be removed.

Use tcf lock to protect skbedit action struct private data from concurrent
modification in init and dump. Use rcu swap operation to reassign params
pointer under protection of tcf lock. (old params value is not used by
init, so there is no need of standalone rcu dereference step)

Remove rtnl lock assertion that is no longer required.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Buslov 2018-09-03 10:07:15 +03:00 committed by David S. Miller
parent 6ad96bdca8
commit 6d7a8df6df
1 changed files with 14 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

23
net/sched/act_skbedit.c
View File

@ -99,7 +99,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
struct netlink_ext_ack *extack)
{
struct tc_action_net *tn = net_generic(net, skbedit_net_id);
struct tcf_skbedit_params *params_old, *params_new;
struct tcf_skbedit_params *params_new;
struct nlattr *tb[TCA_SKBEDIT_MAX + 1];
struct tc_skbedit *parm;
struct tcf_skbedit *d;
@ -187,8 +187,6 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
}
}
ASSERT_RTNL();
params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
if (unlikely(!params_new)) {
if (ret == ACT_P_CREATED)
@ -210,11 +208,13 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla,
if (flags & SKBEDIT_F_MASK)
params_new->mask = *mask;
spin_lock_bh(&d->tcf_lock);
d->tcf_action = parm->action;
params_old = rtnl_dereference(d->params);
rcu_assign_pointer(d->params, params_new);
if (params_old)
kfree_rcu(params_old, rcu);
rcu_swap_protected(d->params, params_new,
lockdep_is_held(&d->tcf_lock));
spin_unlock_bh(&d->tcf_lock);
if (params_new)
kfree_rcu(params_new, rcu);
if (ret == ACT_P_CREATED)
tcf_idr_insert(tn, *a);
@ -231,12 +231,14 @@ static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
.index = d->tcf_index,
.refcnt = refcount_read(&d->tcf_refcnt) - ref,
.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
.action = d->tcf_action,
};
u64 pure_flags = 0;
struct tcf_t t;
params = rtnl_dereference(d->params);
spin_lock_bh(&d->tcf_lock);
params = rcu_dereference_protected(d->params,
lockdep_is_held(&d->tcf_lock));
opt.action = d->tcf_action;
if (nla_put(skb, TCA_SKBEDIT_PARMS, sizeof(opt), &opt))
goto nla_put_failure;
@ -264,9 +266,12 @@ static int tcf_skbedit_dump(struct sk_buff *skb, struct tc_action *a,
tcf_tm_dump(&t, &d->tcf_tm);
if (nla_put_64bit(skb, TCA_SKBEDIT_TM, sizeof(t), &t, TCA_SKBEDIT_PAD))
goto nla_put_failure;
spin_unlock_bh(&d->tcf_lock);
return skb->len;
nla_put_failure:
spin_unlock_bh(&d->tcf_lock);
nlmsg_trim(skb, b);
return -1;
}