| Message ID | 1526308035-12484-2-git-send-email-vladbu@mellanox.com |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Pablo Neira |
| Headers | show |
| Series | Modify action API for implementing lockless actions | expand |
Mon, May 14, 2018 at 04:27:02PM CEST, vladbu@mellanox.com wrote: >Implement functions to atomically update and free action cookie >using rcu mechanism. > >Signed-off-by: Vlad Buslov <vladbu@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Vlad,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on net/master]
[also build test WARNING on v4.17-rc5 next-20180514]
[cannot apply to net-next/master]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Vlad-Buslov/Modify-action-API-for-implementing-lockless-actions/20180515-025420
reproduce:
# apt-get install sparse
make ARCH=x86_64 allmodconfig
make C=1 CF=-D__CHECK_ENDIAN__
sparse warnings: (new ones prefixed by >>)
>> net/sched/act_api.c:71:15: sparse: incorrect type in initializer (different address spaces) @@ expected struct tc_cookie [noderef] <asn:4>*__ret @@ got [noderef] <asn:4>*__ret @@
net/sched/act_api.c:71:15: expected struct tc_cookie [noderef] <asn:4>*__ret
net/sched/act_api.c:71:15: got struct tc_cookie *new_cookie
>> net/sched/act_api.c:71:13: sparse: incorrect type in assignment (different address spaces) @@ expected struct tc_cookie *old @@ got struct tc_cookie [noderef] <struct tc_cookie *old @@
net/sched/act_api.c:71:13: expected struct tc_cookie *old
net/sched/act_api.c:71:13: got struct tc_cookie [noderef] <asn:4>*[assigned] __ret
>> net/sched/act_api.c:132:48: sparse: dereference of noderef expression
vim +71 net/sched/act_api.c
65
66 static void tcf_set_action_cookie(struct tc_cookie __rcu **old_cookie,
67 struct tc_cookie *new_cookie)
68 {
69 struct tc_cookie *old;
70
> 71 old = xchg(old_cookie, new_cookie);
72 if (old)
73 call_rcu(&old->rcu, tcf_free_cookie_rcu);
74 }
75
76 /* XXX: For standalone actions, we don't need a RCU grace period either, because
77 * actions are always connected to filters and filters are already destroyed in
78 * RCU callbacks, so after a RCU grace period actions are already disconnected
79 * from filters. Readers later can not find us.
80 */
81 static void free_tcf(struct tc_action *p)
82 {
83 free_percpu(p->cpu_bstats);
84 free_percpu(p->cpu_qstats);
85
86 tcf_set_action_cookie(&p->act_cookie, NULL);
87 if (p->goto_chain)
88 tcf_action_goto_chain_fini(p);
89
90 kfree(p);
91 }
92
93 static void tcf_idr_remove(struct tcf_idrinfo *idrinfo, struct tc_action *p)
94 {
95 spin_lock_bh(&idrinfo->lock);
96 idr_remove(&idrinfo->action_idr, p->tcfa_index);
97 spin_unlock_bh(&idrinfo->lock);
98 gen_kill_estimator(&p->tcfa_rate_est);
99 free_tcf(p);
100 }
101
102 int __tcf_idr_release(struct tc_action *p, bool bind, bool strict)
103 {
104 int ret = 0;
105
106 ASSERT_RTNL();
107
108 if (p) {
109 if (bind)
110 p->tcfa_bindcnt--;
111 else if (strict && p->tcfa_bindcnt > 0)
112 return -EPERM;
113
114 p->tcfa_refcnt--;
115 if (p->tcfa_bindcnt <= 0 && p->tcfa_refcnt <= 0) {
116 if (p->ops->cleanup)
117 p->ops->cleanup(p);
118 tcf_idr_remove(p->idrinfo, p);
119 ret = ACT_P_DELETED;
120 }
121 }
122
123 return ret;
124 }
125 EXPORT_SYMBOL(__tcf_idr_release);
126
127 static size_t tcf_action_shared_attrs_size(const struct tc_action *act)
128 {
129 u32 cookie_len = 0;
130
131 if (act->act_cookie)
> 132 cookie_len = nla_total_size(act->act_cookie->len);
133
134 return nla_total_size(0) /* action number nested */
135 + nla_total_size(IFNAMSIZ) /* TCA_ACT_KIND */
136 + cookie_len /* TCA_ACT_COOKIE */
137 + nla_total_size(0) /* TCA_ACT_STATS nested */
138 /* TCA_STATS_BASIC */
139 + nla_total_size_64bit(sizeof(struct gnet_stats_basic))
140 /* TCA_STATS_QUEUE */
141 + nla_total_size_64bit(sizeof(struct gnet_stats_queue))
142 + nla_total_size(0) /* TCA_OPTIONS nested */
143 + nla_total_size(sizeof(struct tcf_t)); /* TCA_GACT_TM */
144 }
145
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diff --git a/include/net/act_api.h b/include/net/act_api.h index 9e59ebf..f7b59ef 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -37,7 +37,7 @@ struct tc_action { spinlock_t tcfa_lock; struct gnet_stats_basic_cpu __percpu *cpu_bstats; struct gnet_stats_queue __percpu *cpu_qstats; - struct tc_cookie *act_cookie; + struct tc_cookie __rcu *act_cookie; struct tcf_chain *goto_chain; }; #define tcf_index common.tcfa_index diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h index e828d31..3068cc8 100644 --- a/include/net/pkt_cls.h +++ b/include/net/pkt_cls.h @@ -769,6 +769,7 @@ struct tc_mqprio_qopt_offload { struct tc_cookie { u8 *data; u32 len; + struct rcu_head rcu; }; struct tc_qopt_offload_stats { diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 72251241..ce829a3 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -55,6 +55,24 @@ static void tcf_action_goto_chain_exec(const struct tc_action *a, res->goto_tp = rcu_dereference_bh(chain->filter_chain); } +static void tcf_free_cookie_rcu(struct rcu_head *p) +{ + struct tc_cookie *cookie = container_of(p, struct tc_cookie, rcu); + + kfree(cookie->data); + kfree(cookie); +} + +static void tcf_set_action_cookie(struct tc_cookie __rcu **old_cookie, + struct tc_cookie *new_cookie) +{ + struct tc_cookie *old; + + old = xchg(old_cookie, new_cookie); + if (old) + call_rcu(&old->rcu, tcf_free_cookie_rcu); +} + /* XXX: For standalone actions, we don't need a RCU grace period either, because * actions are always connected to filters and filters are already destroyed in * RCU callbacks, so after a RCU grace period actions are already disconnected @@ -65,10 +83,7 @@ static void free_tcf(struct tc_action *p) free_percpu(p->cpu_bstats); free_percpu(p->cpu_qstats); - if (p->act_cookie) { - kfree(p->act_cookie->data); - kfree(p->act_cookie); - } + tcf_set_action_cookie(&p->act_cookie, NULL); if (p->goto_chain) tcf_action_goto_chain_fini(p); @@ -567,16 +582,22 @@ tcf_action_dump_1(struct sk_buff *skb, struct tc_action *a, int bind, int ref) int err = -EINVAL; unsigned char *b = skb_tail_pointer(skb); struct nlattr *nest; + struct tc_cookie *cookie; if (nla_put_string(skb, TCA_KIND, a->ops->kind)) goto nla_put_failure; if (tcf_action_copy_stats(skb, a, 0)) goto nla_put_failure; - if (a->act_cookie) { - if (nla_put(skb, TCA_ACT_COOKIE, a->act_cookie->len, - a->act_cookie->data)) + + rcu_read_lock(); + cookie = rcu_dereference(a->act_cookie); + if (cookie) { + if (nla_put(skb, TCA_ACT_COOKIE, cookie->len, cookie->data)) { + rcu_read_unlock(); goto nla_put_failure; + } } + rcu_read_unlock(); nest = nla_nest_start(skb, TCA_OPTIONS); if (nest == NULL) @@ -719,13 +740,8 @@ struct tc_action *tcf_action_init_1(struct net *net, struct tcf_proto *tp, if (err < 0) goto err_mod; - if (name == NULL && tb[TCA_ACT_COOKIE]) { - if (a->act_cookie) { - kfree(a->act_cookie->data); - kfree(a->act_cookie); - } - a->act_cookie = cookie; - } + if (!name && tb[TCA_ACT_COOKIE]) + tcf_set_action_cookie(&a->act_cookie, cookie); /* module count goes up only when brand new policy is created * if it exists and is only bound to in a_o->init() then
Implement functions to atomically update and free action cookie using rcu mechanism. Signed-off-by: Vlad Buslov <vladbu@mellanox.com> --- include/net/act_api.h | 2 +- include/net/pkt_cls.h | 1 + net/sched/act_api.c | 44 ++++++++++++++++++++++++++++++-------------- 3 files changed, 32 insertions(+), 15 deletions(-)