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Message-ID: <20140430163718.9021.34128.stgit@nitbit.x32>
Date: Wed, 30 Apr 2014 09:37:20 -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 06/15] net: sched: fw use RCU
RCU'ify fw classifier.
Signed-off-by: John Fastabend <john.r.fastabend@...el.com>
---
net/sched/cls_fw.c | 108 ++++++++++++++++++++++++++++++++++++----------------
1 file changed, 75 insertions(+), 33 deletions(-)
diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c
index 63a3ce7..5610e8c 100644
--- a/net/sched/cls_fw.c
+++ b/net/sched/cls_fw.c
@@ -34,16 +34,19 @@
struct fw_head {
u32 mask;
struct fw_filter *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 +140,32 @@ 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));
+ 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, *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));
+ call_rcu(&f->rcu, fw_delete_filter);
return 0;
}
}
@@ -171,7 +183,7 @@ 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)
{
- struct fw_head *head = tp->root;
+ struct fw_head *head = rtnl_dereference(tp->root);
struct tcf_exts e;
u32 mask;
int err;
@@ -220,7 +232,7 @@ static int fw_change(struct net *net, struct sk_buff *in_skb,
struct nlattr **tca,
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 nlattr *opt = tca[TCA_OPTIONS];
struct nlattr *tb[TCA_FW_MAX + 1];
@@ -233,10 +245,42 @@ 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);
+
+ 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);
+ 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_assign_pointer(*fp, fnew);
+ call_rcu(&f->rcu, fw_delete_filter);
+
+ *arg = (unsigned long)fnew;
+ return err;
}
if (!handle)
@@ -252,9 +296,7 @@ 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 +305,14 @@ 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);
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_assign_pointer(head->ht[fw_hash(handle)], f);
*arg = (unsigned long)f;
return 0;
@@ -283,7 +324,7 @@ errout:
static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
{
- struct fw_head *head = tp->root;
+ struct fw_head *head = rtnl_dereference(tp->root);
int h;
if (head == NULL)
@@ -295,7 +336,8 @@ static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
for (h = 0; h < HTSIZE; h++) {
struct fw_filter *f;
- for (f = head->ht[h]; f; f = f->next) {
+ for (f = rtnl_dereference(head->ht[h]); f;
+ f = rtnl_dereference(f->next)) {
if (arg->count < arg->skip) {
arg->count++;
continue;
@@ -312,7 +354,7 @@ static void fw_walk(struct tcf_proto *tp, struct tcf_walker *arg)
static int fw_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
struct sk_buff *skb, struct tcmsg *t)
{
- struct fw_head *head = tp->root;
+ struct fw_head *head = rtnl_dereference(tp->root);
struct fw_filter *f = (struct fw_filter *)fh;
unsigned char *b = skb_tail_pointer(skb);
struct nlattr *nest;
--
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