From 1f31fea5a69089a40561548ff5931bc5e4e79b61 Mon Sep 17 00:00:00 2001 From: John Fastabend Date: Fri, 12 Sep 2014 20:07:22 -0700 Subject: [PATCH] net: sched: fw use RCU RCU'ify fw classifier. Signed-off-by: John Fastabend Acked-by: Eric Dumazet Signed-off-by: David S. Miller --- 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 861b03ccfed0..006b45a67fdd 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_INIT_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; + 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_INIT_POINTER(*fp, rtnl_dereference(f->next)); + 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_INIT_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 +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_INIT_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 +325,7 @@ 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 +337,8 @@ 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 +355,7 @@ 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;