From 70da9f0bf999627e50950f6845bd3819ff811085 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 12 Sep 2014 20:06:55 -0700 Subject: [PATCH] net: sched: cls_flow use RCU Signed-off-by: John Fastabend Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/cls_flow.c | 145 +++++++++++++++++++++++++------------------ 1 file changed, 84 insertions(+), 61 deletions(-) diff --git a/net/sched/cls_flow.c b/net/sched/cls_flow.c index 35be16f7c192..95736fa479f3 100644 --- a/net/sched/cls_flow.c +++ b/net/sched/cls_flow.c @@ -34,12 +34,14 @@ struct flow_head { struct list_head filters; + struct rcu_head rcu; }; struct flow_filter { struct list_head list; struct tcf_exts exts; struct tcf_ematch_tree ematches; + struct tcf_proto *tp; struct timer_list perturb_timer; u32 perturb_period; u32 handle; @@ -54,6 +56,7 @@ struct flow_filter { u32 divisor; u32 baseclass; u32 hashrnd; + struct rcu_head rcu; }; static inline u32 addr_fold(void *addr) @@ -276,14 +279,14 @@ static u32 flow_key_get(struct sk_buff *skb, int key, struct flow_keys *flow) static int flow_classify(struct sk_buff *skb, const struct tcf_proto *tp, struct tcf_result *res) { - struct flow_head *head = tp->root; + struct flow_head *head = rcu_dereference_bh(tp->root); struct flow_filter *f; u32 keymask; u32 classid; unsigned int n, key; int r; - list_for_each_entry(f, &head->filters, list) { + list_for_each_entry_rcu(f, &head->filters, list) { u32 keys[FLOW_KEY_MAX + 1]; struct flow_keys flow_keys; @@ -346,13 +349,23 @@ static const struct nla_policy flow_policy[TCA_FLOW_MAX + 1] = { [TCA_FLOW_PERTURB] = { .type = NLA_U32 }, }; +static void flow_destroy_filter(struct rcu_head *head) +{ + struct flow_filter *f = container_of(head, struct flow_filter, rcu); + + del_timer_sync(&f->perturb_timer); + tcf_exts_destroy(f->tp, &f->exts); + tcf_em_tree_destroy(f->tp, &f->ematches); + kfree(f); +} + static int flow_change(struct net *net, struct sk_buff *in_skb, struct tcf_proto *tp, unsigned long base, u32 handle, struct nlattr **tca, unsigned long *arg, bool ovr) { - struct flow_head *head = tp->root; - struct flow_filter *f; + struct flow_head *head = rtnl_dereference(tp->root); + struct flow_filter *fold, *fnew; struct nlattr *opt = tca[TCA_OPTIONS]; struct nlattr *tb[TCA_FLOW_MAX + 1]; struct tcf_exts e; @@ -401,20 +414,42 @@ static int flow_change(struct net *net, struct sk_buff *in_skb, if (err < 0) goto err1; - f = (struct flow_filter *)*arg; - if (f != NULL) { + err = -ENOBUFS; + fnew = kzalloc(sizeof(*fnew), GFP_KERNEL); + if (!fnew) + goto err2; + + fold = (struct flow_filter *)*arg; + if (fold) { err = -EINVAL; - if (f->handle != handle && handle) + if (fold->handle != handle && handle) goto err2; - mode = f->mode; + /* Copy fold into fnew */ + fnew->handle = fold->handle; + fnew->keymask = fold->keymask; + fnew->tp = fold->tp; + + fnew->handle = fold->handle; + fnew->nkeys = fold->nkeys; + fnew->keymask = fold->keymask; + fnew->mode = fold->mode; + fnew->mask = fold->mask; + fnew->xor = fold->xor; + fnew->rshift = fold->rshift; + fnew->addend = fold->addend; + fnew->divisor = fold->divisor; + fnew->baseclass = fold->baseclass; + fnew->hashrnd = fold->hashrnd; + + mode = fold->mode; if (tb[TCA_FLOW_MODE]) mode = nla_get_u32(tb[TCA_FLOW_MODE]); if (mode != FLOW_MODE_HASH && nkeys > 1) goto err2; if (mode == FLOW_MODE_HASH) - perturb_period = f->perturb_period; + perturb_period = fold->perturb_period; if (tb[TCA_FLOW_PERTURB]) { if (mode != FLOW_MODE_HASH) goto err2; @@ -444,83 +479,70 @@ static int flow_change(struct net *net, struct sk_buff *in_skb, if (TC_H_MIN(baseclass) == 0) baseclass = TC_H_MAKE(baseclass, 1); - err = -ENOBUFS; - f = kzalloc(sizeof(*f), GFP_KERNEL); - if (f == NULL) - goto err2; - - f->handle = handle; - f->mask = ~0U; - tcf_exts_init(&f->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE); - - get_random_bytes(&f->hashrnd, 4); - f->perturb_timer.function = flow_perturbation; - f->perturb_timer.data = (unsigned long)f; - init_timer_deferrable(&f->perturb_timer); + fnew->handle = handle; + fnew->mask = ~0U; + fnew->tp = tp; + get_random_bytes(&fnew->hashrnd, 4); + tcf_exts_init(&fnew->exts, TCA_FLOW_ACT, TCA_FLOW_POLICE); } - tcf_exts_change(tp, &f->exts, &e); - tcf_em_tree_change(tp, &f->ematches, &t); + fnew->perturb_timer.function = flow_perturbation; + fnew->perturb_timer.data = (unsigned long)fnew; + init_timer_deferrable(&fnew->perturb_timer); - tcf_tree_lock(tp); + tcf_exts_change(tp, &fnew->exts, &e); + tcf_em_tree_change(tp, &fnew->ematches, &t); if (tb[TCA_FLOW_KEYS]) { - f->keymask = keymask; - f->nkeys = nkeys; + fnew->keymask = keymask; + fnew->nkeys = nkeys; } - f->mode = mode; + fnew->mode = mode; if (tb[TCA_FLOW_MASK]) - f->mask = nla_get_u32(tb[TCA_FLOW_MASK]); + fnew->mask = nla_get_u32(tb[TCA_FLOW_MASK]); if (tb[TCA_FLOW_XOR]) - f->xor = nla_get_u32(tb[TCA_FLOW_XOR]); + fnew->xor = nla_get_u32(tb[TCA_FLOW_XOR]); if (tb[TCA_FLOW_RSHIFT]) - f->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]); + fnew->rshift = nla_get_u32(tb[TCA_FLOW_RSHIFT]); if (tb[TCA_FLOW_ADDEND]) - f->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]); + fnew->addend = nla_get_u32(tb[TCA_FLOW_ADDEND]); if (tb[TCA_FLOW_DIVISOR]) - f->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]); + fnew->divisor = nla_get_u32(tb[TCA_FLOW_DIVISOR]); if (baseclass) - f->baseclass = baseclass; + fnew->baseclass = baseclass; - f->perturb_period = perturb_period; - del_timer(&f->perturb_timer); + fnew->perturb_period = perturb_period; if (perturb_period) - mod_timer(&f->perturb_timer, jiffies + perturb_period); + mod_timer(&fnew->perturb_timer, jiffies + perturb_period); if (*arg == 0) - list_add_tail(&f->list, &head->filters); + list_add_tail_rcu(&fnew->list, &head->filters); + else + list_replace_rcu(&fnew->list, &fold->list); - tcf_tree_unlock(tp); + *arg = (unsigned long)fnew; - *arg = (unsigned long)f; + if (fold) + call_rcu(&fold->rcu, flow_destroy_filter); return 0; err2: tcf_em_tree_destroy(tp, &t); + kfree(fnew); err1: tcf_exts_destroy(tp, &e); return err; } -static void flow_destroy_filter(struct tcf_proto *tp, struct flow_filter *f) -{ - del_timer_sync(&f->perturb_timer); - tcf_exts_destroy(tp, &f->exts); - tcf_em_tree_destroy(tp, &f->ematches); - kfree(f); -} - static int flow_delete(struct tcf_proto *tp, unsigned long arg) { struct flow_filter *f = (struct flow_filter *)arg; - tcf_tree_lock(tp); - list_del(&f->list); - tcf_tree_unlock(tp); - flow_destroy_filter(tp, f); + list_del_rcu(&f->list); + call_rcu(&f->rcu, flow_destroy_filter); return 0; } @@ -532,28 +554,29 @@ static int flow_init(struct tcf_proto *tp) if (head == NULL) return -ENOBUFS; INIT_LIST_HEAD(&head->filters); - tp->root = head; + rcu_assign_pointer(tp->root, head); return 0; } static void flow_destroy(struct tcf_proto *tp) { - struct flow_head *head = tp->root; + struct flow_head *head = rtnl_dereference(tp->root); struct flow_filter *f, *next; list_for_each_entry_safe(f, next, &head->filters, list) { - list_del(&f->list); - flow_destroy_filter(tp, f); + list_del_rcu(&f->list); + call_rcu(&f->rcu, flow_destroy_filter); } - kfree(head); + RCU_INIT_POINTER(tp->root, NULL); + kfree_rcu(head, rcu); } static unsigned long flow_get(struct tcf_proto *tp, u32 handle) { - struct flow_head *head = tp->root; + struct flow_head *head = rtnl_dereference(tp->root); struct flow_filter *f; - list_for_each_entry(f, &head->filters, list) + list_for_each_entry_rcu(f, &head->filters, list) if (f->handle == handle) return (unsigned long)f; return 0; @@ -626,10 +649,10 @@ nla_put_failure: static void flow_walk(struct tcf_proto *tp, struct tcf_walker *arg) { - struct flow_head *head = tp->root; + struct flow_head *head = rtnl_dereference(tp->root); struct flow_filter *f; - list_for_each_entry(f, &head->filters, list) { + list_for_each_entry_rcu(f, &head->filters, list) { if (arg->count < arg->skip) goto skip; if (arg->fn(tp, (unsigned long)f, arg) < 0) { -- 2.20.1