| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Tue, 09 Sep 2014 05:48:38 -0700
From: Eric Dumazet <eric.dumazet@...il.com>
To: John Fastabend <john.fastabend@...il.com>
Cc: xiyou.wangcong@...il.com, davem@...emloft.net, jhs@...atatu.com,
netdev@...r.kernel.org, paulmck@...ux.vnet.ibm.com,
brouer@...hat.com
Subject: Re: [net-next PATCH v3 06/15] net: sched: fw use RCU
On Mon, 2014-09-08 at 22:56 -0700, John Fastabend wrote:
> RCU'ify fw classifier.
>
> Signed-off-by: John Fastabend <john.r.fastabend@...el.com>
> ---
> net/sched/cls_fw.c | 111 ++++++++++++++++++++++++++++++++++++----------------
> 1 file changed, 77 insertions(+), 34 deletions(-)
>
> diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
> index 861b03c..4809500 100644
> --- a/net/sched/cls_fw.c
> +++ b/net/sched/cls_fw.c
> @@ -33,17 +33,20 @@
>
> struct fw_head {
> u32 mask;
> - struct fw_filter *ht[HTSIZE];
> + struct fw_filter __rcu *ht[HTSIZE];
> + struct rcu_head rcu;
> };
>
> struct fw_filter {
> - struct fw_filter *next;
> + struct fw_filter __rcu *next;
> u32 id;
> struct tcf_result res;
> #ifdef CONFIG_NET_CLS_IND
> int ifindex;
> #endif /* CONFIG_NET_CLS_IND */
> struct tcf_exts exts;
> + struct tcf_proto *tp;
> + struct rcu_head rcu;
> };
>
> static u32 fw_hash(u32 handle)
> @@ -56,14 +59,16 @@ static u32 fw_hash(u32 handle)
> static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
> struct tcf_result *res)
> {
> - struct fw_head *head = tp->root;
> + struct fw_head *head = rcu_dereference_bh(tp->root);
> struct fw_filter *f;
> int r;
> u32 id = skb->mark;
>
> if (head != NULL) {
> id &= head->mask;
> - for (f = head->ht[fw_hash(id)]; f; f = f->next) {
> +
> + for (f = rcu_dereference_bh(head->ht[fw_hash(id)]); f;
> + f = rcu_dereference_bh(f->next)) {
> if (f->id == id) {
> *res = f->res;
> #ifdef CONFIG_NET_CLS_IND
> @@ -92,13 +97,14 @@ static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp,
>
> static unsigned long fw_get(struct tcf_proto *tp, u32 handle)
> {
> - struct fw_head *head = tp->root;
> + struct fw_head *head = rtnl_dereference(tp->root);
> struct fw_filter *f;
>
> if (head == NULL)
> return 0;
>
> - for (f = head->ht[fw_hash(handle)]; f; f = f->next) {
> + f = rtnl_dereference(head->ht[fw_hash(handle)]);
> + for (; f; f = rtnl_dereference(f->next)) {
> if (f->id == handle)
> return (unsigned long)f;
> }
> @@ -114,8 +120,11 @@ static int fw_init(struct tcf_proto *tp)
> return 0;
> }
>
> -static void fw_delete_filter(struct tcf_proto *tp, struct fw_filter *f)
> +static void fw_delete_filter(struct rcu_head *head)
> {
> + struct fw_filter *f = container_of(head, struct fw_filter, rcu);
> + struct tcf_proto *tp = f->tp;
> +
> tcf_unbind_filter(tp, &f->res);
> tcf_exts_destroy(tp, &f->exts);
> kfree(f);
> @@ -123,7 +132,7 @@ static void fw_delete_filter(struct tcf_proto *tp, struct fw_filter *f)
>
> static void fw_destroy(struct tcf_proto *tp)
> {
> - struct fw_head *head = tp->root;
> + struct fw_head *head = rtnl_dereference(tp->root);
> struct fw_filter *f;
> int h;
>
> @@ -131,29 +140,33 @@ static void fw_destroy(struct tcf_proto *tp)
> return;
>
> for (h = 0; h < HTSIZE; h++) {
> - while ((f = head->ht[h]) != NULL) {
> - head->ht[h] = f->next;
> - fw_delete_filter(tp, f);
> + while ((f = rtnl_dereference(head->ht[h])) != NULL) {
> + rcu_assign_pointer(head->ht[h],
> + rtnl_dereference(f->next));
RCU_INIT_POINTER()
> + call_rcu(&f->rcu, fw_delete_filter);
> }
> }
> - kfree(head);
> + RCU_INIT_POINTER(tp->root, NULL);
> + kfree_rcu(head, rcu);
> }
>
> static int fw_delete(struct tcf_proto *tp, unsigned long arg)
> {
> - struct fw_head *head = tp->root;
> + struct fw_head *head = rtnl_dereference(tp->root);
> struct fw_filter *f = (struct fw_filter *)arg;
> - struct fw_filter **fp;
> + struct fw_filter __rcu **fp;
> + struct fw_filter *pfp;
>
> if (head == NULL || f == NULL)
> goto out;
>
> - for (fp = &head->ht[fw_hash(f->id)]; *fp; fp = &(*fp)->next) {
> - if (*fp == f) {
> - tcf_tree_lock(tp);
> - *fp = f->next;
> - tcf_tree_unlock(tp);
> - fw_delete_filter(tp, f);
> + fp = &head->ht[fw_hash(f->id)];
> +
> + for (pfp = rtnl_dereference(*fp); pfp;
> + fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
> + if (pfp == f) {
> + rcu_assign_pointer(*fp, rtnl_dereference(f->next));
RCU_INIT_POINTER()
> + call_rcu(&f->rcu, fw_delete_filter);
> return 0;
> }
> }
> @@ -171,7 +184,7 @@ static int
> fw_change_attrs(struct net *net, struct tcf_proto *tp, struct fw_filter *f,
> struct nlattr **tb, struct nlattr **tca, unsigned long base, bool ovr)
> {
> - struct fw_head *head = tp->root;
> + struct fw_head *head = rtnl_dereference(tp->root);
> struct tcf_exts e;
> u32 mask;
> int err;
> @@ -220,7 +233,7 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
> struct nlattr **tca,
> unsigned long *arg, bool ovr)
> {
> - struct fw_head *head = tp->root;
> + struct fw_head *head = rtnl_dereference(tp->root);
> struct fw_filter *f = (struct fw_filter *) *arg;
> struct nlattr *opt = tca[TCA_OPTIONS];
> struct nlattr *tb[TCA_FW_MAX + 1];
> @@ -233,10 +246,42 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
> if (err < 0)
> return err;
>
> - if (f != NULL) {
> + if (f) {
> + struct fw_filter *pfp, *fnew;
> + struct fw_filter __rcu **fp;
> +
> if (f->id != handle && handle)
> return -EINVAL;
> - return fw_change_attrs(net, tp, f, tb, tca, base, ovr);
> +
> + fnew = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
> + if (!fnew)
> + return -ENOBUFS;
> +
> + fnew->id = f->id;
> + fnew->res = f->res;
> +#ifdef CONFIG_NET_CLS_IND
> + fnew->ifindex = f->ifindex;
> +#endif /* CONFIG_NET_CLS_IND */
> + fnew->tp = f->tp;
> +
> + err = fw_change_attrs(net, tp, fnew, tb, tca, base, ovr);
> + if (err < 0) {
> + kfree(fnew);
> + return err;
> + }
> +
> + fp = &head->ht[fw_hash(fnew->id)];
> + for (pfp = rtnl_dereference(*fp); pfp;
> + fp = &pfp->next, pfp = rtnl_dereference(*fp))
> + if (pfp == f)
> + break;
> +
> + rcu_assign_pointer(fnew->next, rtnl_dereference(pfp->next));
RCU_INIT_POINTER()
> + rcu_assign_pointer(*fp, fnew);
This one is fine
> + call_rcu(&f->rcu, fw_delete_filter);
> +
> + *arg = (unsigned long)fnew;
> + return err;
> }
>
> if (!handle)
> @@ -252,9 +297,7 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
> return -ENOBUFS;
> head->mask = mask;
>
> - tcf_tree_lock(tp);
> - tp->root = head;
> - tcf_tree_unlock(tp);
> + rcu_assign_pointer(tp->root, head);
> }
>
> f = kzalloc(sizeof(struct fw_filter), GFP_KERNEL);
> @@ -263,15 +306,14 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
>
> tcf_exts_init(&f->exts, TCA_FW_ACT, TCA_FW_POLICE);
> f->id = handle;
> + f->tp = tp;
>
> err = fw_change_attrs(net, tp, f, tb, tca, base, ovr);
> if (err < 0)
> goto errout;
>
> - f->next = head->ht[fw_hash(handle)];
> - tcf_tree_lock(tp);
> - head->ht[fw_hash(handle)] = f;
> - tcf_tree_unlock(tp);
> + rcu_assign_pointer(f->next, head->ht[fw_hash(handle)]);
RCU_INIT_POINTER()
> + rcu_assign_pointer(head->ht[fw_hash(handle)], f);
This one is fine.
>
> *arg = (unsigned long)f;
> return 0;
> @@ -283,7 +325,7 @@ errout:
Thanks
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists