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2023-12-08 01573e231f18eb2d99162747186f59511f56b64d

 kernel/net/sched/cls_tcindex.c
..
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@@ -1,3 +1,4 @@
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+// SPDX-License-Identifier: GPL-2.0-only
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 /*
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  * net/sched/cls_tcindex.c	Packet classifier for skb->tc_index
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  *
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..
@@ -10,6 +11,7 @@
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 #include <linux/skbuff.h>
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 #include <linux/errno.h>
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 #include <linux/slab.h>
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+#include <linux/refcount.h>
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 #include <net/act_api.h>
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 #include <net/netlink.h>
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 #include <net/pkt_cls.h>
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@@ -25,9 +27,12 @@
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 #define DEFAULT_HASH_SIZE	64	/* optimized for diffserv */
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28
 
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29
 
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+struct tcindex_data;
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+
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 struct tcindex_filter_result {
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 	struct tcf_exts		exts;
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 	struct tcf_result	res;
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+	struct tcindex_data	*p;
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 	struct rcu_work		rwork;
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 };
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38
 
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@@ -48,12 +53,27 @@
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 	u32 hash;		/* hash table size; 0 if undefined */
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 	u32 alloc_hash;		/* allocated size */
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 	u32 fall_through;	/* 0: only classify if explicit match */
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+	refcount_t refcnt;	/* a temporary refcnt for perfect hash */
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 	struct rcu_work rwork;
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 };
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59
 
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 static inline int tcindex_filter_is_set(struct tcindex_filter_result *r)
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 {
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 	return tcf_exts_has_actions(&r->exts) || r->res.classid;
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+}
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+
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+static void tcindex_data_get(struct tcindex_data *p)
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+{
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+	refcount_inc(&p->refcnt);
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+}
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+
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+static void tcindex_data_put(struct tcindex_data *p)
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+{
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+	if (refcount_dec_and_test(&p->refcnt)) {
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+		kfree(p->perfect);
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+		kfree(p->h);
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+		kfree(p);
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+	}
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 }
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78
 
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 static struct tcindex_filter_result *tcindex_lookup(struct tcindex_data *p,
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@@ -131,6 +151,7 @@
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 	p->mask = 0xffff;
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 	p->hash = DEFAULT_HASH_SIZE;
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 	p->fall_through = 1;
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+	refcount_set(&p->refcnt, 1); /* Paired with tcindex_destroy_work() */
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155
 
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 	rcu_assign_pointer(tp->root, p);
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 	return 0;
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@@ -140,6 +161,7 @@
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 {
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 	tcf_exts_destroy(&r->exts);
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 	tcf_exts_put_net(&r->exts);
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+	tcindex_data_put(r->p);
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165
 }
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166
 
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 static void tcindex_destroy_rexts_work(struct work_struct *work)
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@@ -173,7 +195,7 @@
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195
 }
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196
 
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 static int tcindex_delete(struct tcf_proto *tp, void *arg, bool *last,
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-			  struct netlink_ext_ack *extack)
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+			  bool rtnl_held, struct netlink_ext_ack *extack)
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 {
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 	struct tcindex_data *p = rtnl_dereference(tp->root);
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 	struct tcindex_filter_result *r = arg;
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@@ -211,6 +233,8 @@
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 		else
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 			__tcindex_destroy_fexts(f);
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 	} else {
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+		tcindex_data_get(p);
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+
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 		if (tcf_exts_get_net(&r->exts))
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 			tcf_queue_work(&r->rwork, tcindex_destroy_rexts_work);
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 		else
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@@ -227,9 +251,7 @@
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 					      struct tcindex_data,
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 					      rwork);
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253
 
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-	kfree(p->perfect);
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-	kfree(p->h);
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-	kfree(p);
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+	tcindex_data_put(p);
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 }
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256
 
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 static inline int
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@@ -246,11 +268,17 @@
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 	[TCA_TCINDEX_CLASSID]		= { .type = NLA_U32 },
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269
 };
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270
 
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-static int tcindex_filter_result_init(struct tcindex_filter_result *r)
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+static int tcindex_filter_result_init(struct tcindex_filter_result *r,
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+				      struct tcindex_data *p,
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+				      struct net *net)
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 {
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 	memset(r, 0, sizeof(*r));
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-	return tcf_exts_init(&r->exts, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
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+	r->p = p;
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+	return tcf_exts_init(&r->exts, net, TCA_TCINDEX_ACT,
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+			     TCA_TCINDEX_POLICE);
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279
 }
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+
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+static void tcindex_free_perfect_hash(struct tcindex_data *cp);
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282
 
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 static void tcindex_partial_destroy_work(struct work_struct *work)
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 {
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@@ -258,8 +286,11 @@
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 					      struct tcindex_data,
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287
 					      rwork);
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288
 
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-	kfree(p->perfect);
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+	rtnl_lock();
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+	if (p->perfect)
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+		tcindex_free_perfect_hash(p);
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 	kfree(p);
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+	rtnl_unlock();
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 }
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295
 
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 static void tcindex_free_perfect_hash(struct tcindex_data *cp)
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@@ -281,13 +312,11 @@
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312
 		return -ENOMEM;
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313
 
283
314
 	for (i = 0; i < cp->hash; i++) {
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-		err = tcf_exts_init(&cp->perfect[i].exts,
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+		err = tcf_exts_init(&cp->perfect[i].exts, net,
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316
 				    TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
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317
 		if (err < 0)
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318
 			goto errout;
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-#ifdef CONFIG_NET_CLS_ACT
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-		cp->perfect[i].exts.net = net;
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-#endif
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+		cp->perfect[i].p = cp;
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320
 	}
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321
 
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 	return 0;
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@@ -310,10 +339,10 @@
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 	int err, balloc = 0;
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 	struct tcf_exts e;
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341
 
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-	err = tcf_exts_init(&e, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
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+	err = tcf_exts_init(&e, net, TCA_TCINDEX_ACT, TCA_TCINDEX_POLICE);
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343
 	if (err < 0)
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 		return err;
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-	err = tcf_exts_validate(net, tp, tb, est, &e, ovr, extack);
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+	err = tcf_exts_validate(net, tp, tb, est, &e, ovr, true, extack);
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346
 	if (err < 0)
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 		goto errout;
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348
 
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@@ -332,6 +361,7 @@
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 	cp->alloc_hash = p->alloc_hash;
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362
 	cp->fall_through = p->fall_through;
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 	cp->tp = tp;
364
+	refcount_set(&cp->refcnt, 1); /* Paired with tcindex_destroy_work() */
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365
 
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 	if (tb[TCA_TCINDEX_HASH])
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 		cp->hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);
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@@ -368,7 +398,7 @@
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398
 	}
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399
 	cp->h = p->h;
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400
 
371
-	err = tcindex_filter_result_init(&new_filter_result);
401
+	err = tcindex_filter_result_init(&new_filter_result, cp, net);
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402
 	if (err < 0)
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403
 		goto errout_alloc;
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404
 	if (old_r)
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@@ -436,7 +466,7 @@
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466
 			goto errout_alloc;
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467
 		f->key = handle;
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 		f->next = NULL;
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-		err = tcindex_filter_result_init(&f->result);
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+		err = tcindex_filter_result_init(&f->result, cp, net);
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470
 		if (err < 0) {
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471
 			kfree(f);
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472
 			goto errout_alloc;
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@@ -449,7 +479,7 @@
449
479
 	}
450
480
 
451
481
 	if (old_r && old_r != r) {
452
-		err = tcindex_filter_result_init(old_r);
482
+		err = tcindex_filter_result_init(old_r, cp, net);
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483
 		if (err < 0) {
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484
 			kfree(f);
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485
 			goto errout_alloc;
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@@ -500,7 +530,7 @@
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530
 tcindex_change(struct net *net, struct sk_buff *in_skb,
501
531
 	       struct tcf_proto *tp, unsigned long base, u32 handle,
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532
 	       struct nlattr **tca, void **arg, bool ovr,
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-	       struct netlink_ext_ack *extack)
533
+	       bool rtnl_held, struct netlink_ext_ack *extack)
504
534
 {
505
535
 	struct nlattr *opt = tca[TCA_OPTIONS];
506
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 	struct nlattr *tb[TCA_TCINDEX_MAX + 1];
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@@ -510,12 +540,13 @@
510
540
 
511
541
 	pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
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542
 	    "p %p,r %p,*arg %p\n",
513
-	    tp, handle, tca, arg, opt, p, r, arg ? *arg : NULL);
543
+	    tp, handle, tca, arg, opt, p, r, *arg);
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544
 
515
545
 	if (!opt)
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546
 		return 0;
517
547
 
518
-	err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy, NULL);
548
+	err = nla_parse_nested_deprecated(tb, TCA_TCINDEX_MAX, opt,
549
+					  tcindex_policy, NULL);
519
550
 	if (err < 0)
520
551
 		return err;
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552
 
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@@ -523,7 +554,8 @@
523
554
 				 tca[TCA_RATE], ovr, extack);
524
555
 }
525
556
 
526
-static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
557
+static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker,
558
+			 bool rtnl_held)
527
559
 {
528
560
 	struct tcindex_data *p = rtnl_dereference(tp->root);
529
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 	struct tcindex_filter *f, *next;
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@@ -559,7 +591,7 @@
559
591
 	}
560
592
 }
561
593
 
562
-static void tcindex_destroy(struct tcf_proto *tp,
594
+static void tcindex_destroy(struct tcf_proto *tp, bool rtnl_held,
563
595
 			    struct netlink_ext_ack *extack)
564
596
 {
565
597
 	struct tcindex_data *p = rtnl_dereference(tp->root);
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@@ -570,6 +602,14 @@
570
602
 	if (p->perfect) {
571
603
 		for (i = 0; i < p->hash; i++) {
572
604
 			struct tcindex_filter_result *r = p->perfect + i;
605
+
606
+			/* tcf_queue_work() does not guarantee the ordering we
607
+			 * want, so we have to take this refcnt temporarily to
608
+			 * ensure 'p' is freed after all tcindex_filter_result
609
+			 * here. Imperfect hash does not need this, because it
610
+			 * uses linked lists rather than an array.
611
+			 */
612
+			tcindex_data_get(p);
573
613
 
574
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 			tcf_unbind_filter(tp, &r->res);
575
615
 			if (tcf_exts_get_net(&r->exts))
..
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@@ -586,7 +626,7 @@
586
626
 
587
627
 		for (f = rtnl_dereference(p->h[i]); f; f = next) {
588
628
 			next = rtnl_dereference(f->next);
589
-			tcindex_delete(tp, &f->result, &last, NULL);
629
+			tcindex_delete(tp, &f->result, &last, rtnl_held, NULL);
590
630
 		}
591
631
 	}
592
632
 
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@@ -595,7 +635,7 @@
595
635
 
596
636
 
597
637
 static int tcindex_dump(struct net *net, struct tcf_proto *tp, void *fh,
598
-			struct sk_buff *skb, struct tcmsg *t)
638
+			struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
599
639
 {
600
640
 	struct tcindex_data *p = rtnl_dereference(tp->root);
601
641
 	struct tcindex_filter_result *r = fh;
..
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@@ -605,7 +645,7 @@
605
645
 		 tp, fh, skb, t, p, r);
606
646
 	pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);
607
647
 
608
-	nest = nla_nest_start(skb, TCA_OPTIONS);
648
+	nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
609
649
 	if (nest == NULL)
610
650
 		goto nla_put_failure;
611
651