forked from Minki/linux
net: sched: make cls_u32 lockless
Make cls_u32 classifier safe to run without holding lock. This patch
converts statistics that are kept in read section u32_classify into
per cpu counters.
This patch was tested with a tight u32 filter add/delete loop while
generating traffic with pktgen. By running pktgen on vlan devices
created on top of a physical device we can hit the qdisc layer
correctly. For ingress qdisc's a loopback cable was used.
for i in {1..100}; do
q=`echo $i%8|bc`;
echo -n "u32 tos: iteration $i on queue $q";
tc filter add dev p3p2 parent $p prio $i u32 match ip tos 0x10 0xff \
action skbedit queue_mapping $q;
sleep 1;
tc filter del dev p3p2 prio $i;
echo -n "u32 tos hash table: iteration $i on queue $q";
tc filter add dev p3p2 parent $p protocol ip prio $i handle 628: u32 divisor 1
tc filter add dev p3p2 parent $p protocol ip prio $i u32 \
match ip protocol 17 0xff link 628: offset at 0 mask 0xf00 shift 6 plus 0
tc filter add dev p3p2 parent $p protocol ip prio $i u32 \
ht 628:0 match ip tos 0x10 0xff action skbedit queue_mapping $q
sleep 2;
tc filter del dev p3p2 prio $i
sleep 1;
done
Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
John Fastabend
David S. Miller
parent
f4f640502d
commit
8f787cd1cc
@ -36,6 +36,7 @@
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/percpu.h>
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#include <linux/rtnetlink.h>
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#include <linux/skbuff.h>
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#include <linux/bitmap.h>
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@ -44,16 +45,16 @@
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#include <net/pkt_cls.h>
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struct tc_u_knode {
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struct tc_u_knode *next;
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struct tc_u_knode __rcu *next;
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u32 handle;
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struct tc_u_hnode *ht_up;
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struct tc_u_hnode __rcu *ht_up;
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struct tcf_exts exts;
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#ifdef CONFIG_NET_CLS_IND
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int ifindex;
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#endif
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u8 fshift;
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struct tcf_result res;
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struct tc_u_hnode *ht_down;
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struct tc_u_hnode __rcu *ht_down;
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#ifdef CONFIG_CLS_U32_PERF
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struct tc_u32_pcnt __percpu *pf;
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#endif
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@ -62,24 +63,28 @@ struct tc_u_knode {
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u32 mask;
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u32 __percpu *pcpu_success;
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#endif
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struct tcf_proto *tp;
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struct tc_u32_sel sel;
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struct rcu_head rcu;
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};
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struct tc_u_hnode {
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struct tc_u_hnode *next;
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struct tc_u_hnode __rcu *next;
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u32 handle;
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u32 prio;
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struct tc_u_common *tp_c;
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int refcnt;
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unsigned int divisor;
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struct tc_u_knode *ht[1];
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struct tc_u_knode __rcu *ht[1];
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struct rcu_head rcu;
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};
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struct tc_u_common {
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struct tc_u_hnode *hlist;
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struct tc_u_hnode __rcu *hlist;
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struct Qdisc *q;
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int refcnt;
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u32 hgenerator;
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struct rcu_head rcu;
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};
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static inline unsigned int u32_hash_fold(__be32 key,
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@ -98,7 +103,7 @@ static int u32_classify(struct sk_buff *skb, const struct tcf_proto *tp, struct
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unsigned int off;
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} stack[TC_U32_MAXDEPTH];
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struct tc_u_hnode *ht = tp->root;
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struct tc_u_hnode *ht = rcu_dereference_bh(tp->root);
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unsigned int off = skb_network_offset(skb);
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struct tc_u_knode *n;
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int sdepth = 0;
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@ -110,7 +115,7 @@ static int u32_classify(struct sk_buff *skb, const struct tcf_proto *tp, struct
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int i, r;
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next_ht:
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n = ht->ht[sel];
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n = rcu_dereference_bh(ht->ht[sel]);
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next_knode:
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if (n) {
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@ -123,7 +128,7 @@ next_knode:
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#ifdef CONFIG_CLS_U32_MARK
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if ((skb->mark & n->mask) != n->val) {
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n = n->next;
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n = rcu_dereference_bh(n->next);
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goto next_knode;
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} else {
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__this_cpu_inc(*n->pcpu_success);
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@ -141,7 +146,7 @@ next_knode:
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if (!data)
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goto out;
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if ((*data ^ key->val) & key->mask) {
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n = n->next;
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n = rcu_dereference_bh(n->next);
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goto next_knode;
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}
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#ifdef CONFIG_CLS_U32_PERF
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@ -149,14 +154,16 @@ next_knode:
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j++;
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#endif
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}
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if (n->ht_down == NULL) {
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ht = rcu_dereference_bh(n->ht_down);
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if (!ht) {
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check_terminal:
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if (n->sel.flags & TC_U32_TERMINAL) {
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*res = n->res;
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#ifdef CONFIG_NET_CLS_IND
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if (!tcf_match_indev(skb, n->ifindex)) {
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n = n->next;
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n = rcu_dereference_bh(n->next);
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goto next_knode;
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}
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#endif
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@ -165,13 +172,13 @@ check_terminal:
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#endif
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r = tcf_exts_exec(skb, &n->exts, res);
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if (r < 0) {
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n = n->next;
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n = rcu_dereference_bh(n->next);
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goto next_knode;
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}
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return r;
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}
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n = n->next;
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n = rcu_dereference_bh(n->next);
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goto next_knode;
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}
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@ -182,7 +189,7 @@ check_terminal:
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stack[sdepth].off = off;
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sdepth++;
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ht = n->ht_down;
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ht = rcu_dereference_bh(n->ht_down);
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sel = 0;
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if (ht->divisor) {
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__be32 *data, hdata;
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@ -224,7 +231,7 @@ check_terminal:
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/* POP */
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if (sdepth--) {
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n = stack[sdepth].knode;
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ht = n->ht_up;
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ht = rcu_dereference_bh(n->ht_up);
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off = stack[sdepth].off;
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goto check_terminal;
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}
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@ -241,7 +248,9 @@ u32_lookup_ht(struct tc_u_common *tp_c, u32 handle)
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{
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struct tc_u_hnode *ht;
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for (ht = tp_c->hlist; ht; ht = ht->next)
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for (ht = rtnl_dereference(tp_c->hlist);
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ht;
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ht = rtnl_dereference(ht->next))
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if (ht->handle == handle)
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break;
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@ -258,7 +267,9 @@ u32_lookup_key(struct tc_u_hnode *ht, u32 handle)
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if (sel > ht->divisor)
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goto out;
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for (n = ht->ht[sel]; n; n = n->next)
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for (n = rtnl_dereference(ht->ht[sel]);
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n;
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n = rtnl_dereference(n->next))
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if (n->handle == handle)
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break;
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out:
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@ -272,7 +283,7 @@ static unsigned long u32_get(struct tcf_proto *tp, u32 handle)
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struct tc_u_common *tp_c = tp->data;
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if (TC_U32_HTID(handle) == TC_U32_ROOT)
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ht = tp->root;
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ht = rtnl_dereference(tp->root);
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else
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ht = u32_lookup_ht(tp_c, TC_U32_HTID(handle));
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@ -293,6 +304,9 @@ static u32 gen_new_htid(struct tc_u_common *tp_c)
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{
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int i = 0x800;
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/* hgenerator only used inside rtnl lock it is safe to increment
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* without read _copy_ update semantics
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*/
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do {
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if (++tp_c->hgenerator == 0x7FF)
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tp_c->hgenerator = 1;
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@ -328,11 +342,11 @@ static int u32_init(struct tcf_proto *tp)
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}
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tp_c->refcnt++;
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root_ht->next = tp_c->hlist;
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tp_c->hlist = root_ht;
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RCU_INIT_POINTER(root_ht->next, tp_c->hlist);
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rcu_assign_pointer(tp_c->hlist, root_ht);
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root_ht->tp_c = tp_c;
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tp->root = root_ht;
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rcu_assign_pointer(tp->root, root_ht);
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tp->data = tp_c;
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return 0;
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}
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@ -350,19 +364,27 @@ static int u32_destroy_key(struct tcf_proto *tp, struct tc_u_knode *n)
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return 0;
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}
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static void u32_delete_key_rcu(struct rcu_head *rcu)
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{
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struct tc_u_knode *key = container_of(rcu, struct tc_u_knode, rcu);
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u32_destroy_key(key->tp, key);
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}
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static int u32_delete_key(struct tcf_proto *tp, struct tc_u_knode *key)
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{
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struct tc_u_knode **kp;
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struct tc_u_knode __rcu **kp;
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struct tc_u_knode *pkp;
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struct tc_u_hnode *ht = key->ht_up;
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if (ht) {
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for (kp = &ht->ht[TC_U32_HASH(key->handle)]; *kp; kp = &(*kp)->next) {
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if (*kp == key) {
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tcf_tree_lock(tp);
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*kp = key->next;
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tcf_tree_unlock(tp);
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kp = &ht->ht[TC_U32_HASH(key->handle)];
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for (pkp = rtnl_dereference(*kp); pkp;
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kp = &pkp->next, pkp = rtnl_dereference(*kp)) {
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if (pkp == key) {
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RCU_INIT_POINTER(*kp, key->next);
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u32_destroy_key(tp, key);
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call_rcu(&key->rcu, u32_delete_key_rcu);
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return 0;
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}
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}
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@ -371,16 +393,16 @@ static int u32_delete_key(struct tcf_proto *tp, struct tc_u_knode *key)
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return 0;
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}
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static void u32_clear_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht)
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static void u32_clear_hnode(struct tc_u_hnode *ht)
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{
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struct tc_u_knode *n;
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unsigned int h;
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for (h = 0; h <= ht->divisor; h++) {
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while ((n = ht->ht[h]) != NULL) {
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ht->ht[h] = n->next;
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u32_destroy_key(tp, n);
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while ((n = rtnl_dereference(ht->ht[h])) != NULL) {
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RCU_INIT_POINTER(ht->ht[h],
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rtnl_dereference(n->next));
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call_rcu(&n->rcu, u32_delete_key_rcu);
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}
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}
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}
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@ -388,28 +410,31 @@ static void u32_clear_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht)
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static int u32_destroy_hnode(struct tcf_proto *tp, struct tc_u_hnode *ht)
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{
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struct tc_u_common *tp_c = tp->data;
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struct tc_u_hnode **hn;
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struct tc_u_hnode __rcu **hn;
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struct tc_u_hnode *phn;
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WARN_ON(ht->refcnt);
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u32_clear_hnode(tp, ht);
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u32_clear_hnode(ht);
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for (hn = &tp_c->hlist; *hn; hn = &(*hn)->next) {
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if (*hn == ht) {
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*hn = ht->next;
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kfree(ht);
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hn = &tp_c->hlist;
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for (phn = rtnl_dereference(*hn);
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phn;
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hn = &phn->next, phn = rtnl_dereference(*hn)) {
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if (phn == ht) {
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RCU_INIT_POINTER(*hn, ht->next);
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kfree_rcu(ht, rcu);
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return 0;
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}
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}
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WARN_ON(1);
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return -ENOENT;
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}
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static void u32_destroy(struct tcf_proto *tp)
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{
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struct tc_u_common *tp_c = tp->data;
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struct tc_u_hnode *root_ht = tp->root;
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struct tc_u_hnode *root_ht = rtnl_dereference(tp->root);
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WARN_ON(root_ht == NULL);
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@ -421,17 +446,16 @@ static void u32_destroy(struct tcf_proto *tp)
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tp->q->u32_node = NULL;
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for (ht = tp_c->hlist; ht; ht = ht->next) {
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for (ht = rtnl_dereference(tp_c->hlist);
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ht;
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ht = rtnl_dereference(ht->next)) {
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ht->refcnt--;
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u32_clear_hnode(tp, ht);
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u32_clear_hnode(ht);
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}
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while ((ht = tp_c->hlist) != NULL) {
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tp_c->hlist = ht->next;
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WARN_ON(ht->refcnt != 0);
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kfree(ht);
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while ((ht = rtnl_dereference(tp_c->hlist)) != NULL) {
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RCU_INIT_POINTER(tp_c->hlist, ht->next);
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kfree_rcu(ht, rcu);
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}
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kfree(tp_c);
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@ -443,6 +467,7 @@ static void u32_destroy(struct tcf_proto *tp)
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static int u32_delete(struct tcf_proto *tp, unsigned long arg)
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{
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struct tc_u_hnode *ht = (struct tc_u_hnode *)arg;
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struct tc_u_hnode *root_ht = rtnl_dereference(tp->root);
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if (ht == NULL)
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return 0;
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@ -450,7 +475,7 @@ static int u32_delete(struct tcf_proto *tp, unsigned long arg)
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if (TC_U32_KEY(ht->handle))
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return u32_delete_key(tp, (struct tc_u_knode *)ht);
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if (tp->root == ht)
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if (root_ht == ht)
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return -EINVAL;
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if (ht->refcnt == 1) {
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@ -473,7 +498,9 @@ static u32 gen_new_kid(struct tc_u_hnode *ht, u32 handle)
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if (!bitmap)
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return handle | 0xFFF;
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for (n = ht->ht[TC_U32_HASH(handle)]; n; n = n->next)
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for (n = rtnl_dereference(ht->ht[TC_U32_HASH(handle)]);
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n;
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n = rtnl_dereference(n->next))
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set_bit(TC_U32_NODE(n->handle), bitmap);
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i = find_next_zero_bit(bitmap, NR_U32_NODE, 0x800);
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@ -523,10 +550,8 @@ static int u32_set_parms(struct net *net, struct tcf_proto *tp,
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ht_down->refcnt++;
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}
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tcf_tree_lock(tp);
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ht_old = n->ht_down;
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n->ht_down = ht_down;
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tcf_tree_unlock(tp);
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ht_old = rtnl_dereference(n->ht_down);
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rcu_assign_pointer(n->ht_down, ht_down);
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if (ht_old)
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ht_old->refcnt--;
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@ -606,8 +631,8 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
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ht->divisor = divisor;
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ht->handle = handle;
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ht->prio = tp->prio;
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ht->next = tp_c->hlist;
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tp_c->hlist = ht;
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RCU_INIT_POINTER(ht->next, tp_c->hlist);
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rcu_assign_pointer(tp_c->hlist, ht);
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*arg = (unsigned long)ht;
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return 0;
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}
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@ -615,7 +640,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
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if (tb[TCA_U32_HASH]) {
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htid = nla_get_u32(tb[TCA_U32_HASH]);
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if (TC_U32_HTID(htid) == TC_U32_ROOT) {
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ht = tp->root;
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ht = rtnl_dereference(tp->root);
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htid = ht->handle;
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} else {
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ht = u32_lookup_ht(tp->data, TC_U32_HTID(htid));
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@ -623,7 +648,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
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return -EINVAL;
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}
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} else {
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ht = tp->root;
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ht = rtnl_dereference(tp->root);
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htid = ht->handle;
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}
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@ -660,6 +685,7 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
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n->handle = handle;
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n->fshift = s->hmask ? ffs(ntohl(s->hmask)) - 1 : 0;
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tcf_exts_init(&n->exts, TCA_U32_ACT, TCA_U32_POLICE);
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n->tp = tp;
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#ifdef CONFIG_CLS_U32_MARK
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n->pcpu_success = alloc_percpu(u32);
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@ -675,21 +701,23 @@ static int u32_change(struct net *net, struct sk_buff *in_skb,
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err = u32_set_parms(net, tp, base, ht, n, tb, tca[TCA_RATE], ovr);
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if (err == 0) {
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struct tc_u_knode **ins;
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for (ins = &ht->ht[TC_U32_HASH(handle)]; *ins; ins = &(*ins)->next)
|
||||
if (TC_U32_NODE(handle) < TC_U32_NODE((*ins)->handle))
|
||||
struct tc_u_knode __rcu **ins;
|
||||
struct tc_u_knode *pins;
|
||||
|
||||
ins = &ht->ht[TC_U32_HASH(handle)];
|
||||
for (pins = rtnl_dereference(*ins); pins;
|
||||
ins = &pins->next, pins = rtnl_dereference(*ins))
|
||||
if (TC_U32_NODE(handle) < TC_U32_NODE(pins->handle))
|
||||
break;
|
||||
|
||||
n->next = *ins;
|
||||
tcf_tree_lock(tp);
|
||||
*ins = n;
|
||||
tcf_tree_unlock(tp);
|
||||
RCU_INIT_POINTER(n->next, pins);
|
||||
rcu_assign_pointer(*ins, n);
|
||||
|
||||
*arg = (unsigned long)n;
|
||||
return 0;
|
||||
}
|
||||
#ifdef CONFIG_CLS_U32_PERF
|
||||
kfree(n->pf);
|
||||
free_percpu(n->pf);
|
||||
#endif
|
||||
kfree(n);
|
||||
return err;
|
||||
@ -705,7 +733,9 @@ static void u32_walk(struct tcf_proto *tp, struct tcf_walker *arg)
|
||||
if (arg->stop)
|
||||
return;
|
||||
|
||||
for (ht = tp_c->hlist; ht; ht = ht->next) {
|
||||
for (ht = rtnl_dereference(tp_c->hlist);
|
||||
ht;
|
||||
ht = rtnl_dereference(ht->next)) {
|
||||
if (ht->prio != tp->prio)
|
||||
continue;
|
||||
if (arg->count >= arg->skip) {
|
||||
@ -716,7 +746,9 @@ static void u32_walk(struct tcf_proto *tp, struct tcf_walker *arg)
|
||||
}
|
||||
arg->count++;
|
||||
for (h = 0; h <= ht->divisor; h++) {
|
||||
for (n = ht->ht[h]; n; n = n->next) {
|
||||
for (n = rtnl_dereference(ht->ht[h]);
|
||||
n;
|
||||
n = rtnl_dereference(n->next)) {
|
||||
if (arg->count < arg->skip) {
|
||||
arg->count++;
|
||||
continue;
|
||||
@ -735,6 +767,7 @@ static int u32_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
|
||||
struct sk_buff *skb, struct tcmsg *t)
|
||||
{
|
||||
struct tc_u_knode *n = (struct tc_u_knode *)fh;
|
||||
struct tc_u_hnode *ht_up, *ht_down;
|
||||
struct nlattr *nest;
|
||||
|
||||
if (n == NULL)
|
||||
@ -762,7 +795,9 @@ static int u32_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
|
||||
sizeof(n->sel) + n->sel.nkeys*sizeof(struct tc_u32_key),
|
||||
&n->sel))
|
||||
goto nla_put_failure;
|
||||
if (n->ht_up) {
|
||||
|
||||
ht_up = rtnl_dereference(n->ht_up);
|
||||
if (ht_up) {
|
||||
u32 htid = n->handle & 0xFFFFF000;
|
||||
if (nla_put_u32(skb, TCA_U32_HASH, htid))
|
||||
goto nla_put_failure;
|
||||
@ -770,8 +805,10 @@ static int u32_dump(struct net *net, struct tcf_proto *tp, unsigned long fh,
|
||||
if (n->res.classid &&
|
||||
nla_put_u32(skb, TCA_U32_CLASSID, n->res.classid))
|
||||
goto nla_put_failure;
|
||||
if (n->ht_down &&
|
||||
nla_put_u32(skb, TCA_U32_LINK, n->ht_down->handle))
|
||||
|
||||
ht_down = rtnl_dereference(n->ht_down);
|
||||
if (ht_down &&
|
||||
nla_put_u32(skb, TCA_U32_LINK, ht_down->handle))
|
||||
goto nla_put_failure;
|
||||
|
||||
#ifdef CONFIG_CLS_U32_MARK
|
||||
|
||||
Loading…
Reference in New Issue
Block a user