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Date: Wed, 30 Apr 2014 09:36:48 -0700
From: John Fastabend <john.fastabend@...il.com>
To: xiyou.wangcong@...il.com, jhs@...atatu.com
Cc: netdev@...r.kernel.org, davem@...emloft.net, eric.dumazet@...il.com
Subject: [RFC PATCH 05/15] net: sched: cls_flow use RCU
Signed-off-by: John Fastabend <john.r.fastabend@...el.com>
---
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 257029c..272337f 100644
--- a/net/sched/cls_flow.c
+++ b/net/sched/cls_flow.c
@@ -34,12 +34,15 @@
struct flow_head {
struct list_head filters;
+ struct rcu_head rcu;
};
struct flow_filter {
struct list_head list;
+ struct rcu_head rcu;
struct tcf_exts exts;
struct tcf_ematch_tree ematches;
+ struct tcf_proto *tp;
struct timer_list perturb_timer;
u32 perturb_period;
u32 handle;
@@ -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)
{
- 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) {
--
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