1 files changed, 132 insertions, 94 deletions

diff --git a/net/sched/cls_route.c b/net/sched/cls_route.c
index dd9fc2523c76..ba96deacf27c 100644
--- a/net/sched/cls_route.c
+++ b/net/sched/cls_route.c
@@ -29,25 +29,26 @@
  *    are mutually  exclusive.
  * 3. "to TAG from ANY" has higher priority, than "to ANY from XXX"
  */
-
 struct route4_fastmap {
-	struct route4_filter	*filter;
-	u32			id;
-	int			iif;
+	struct route4_filter		*filter;
+	u32				id;
+	int				iif;
 };
 
 struct route4_head {
-	struct route4_fastmap	fastmap[16];
-	struct route4_bucket	*table[256 + 1];
+	struct route4_fastmap		fastmap[16];
+	struct route4_bucket __rcu	*table[256 + 1];
+	struct rcu_head			rcu;
 };
 
 struct route4_bucket {
 	/* 16 FROM buckets + 16 IIF buckets + 1 wildcard bucket */
-	struct route4_filter	*ht[16 + 16 + 1];
+	struct route4_filter __rcu	*ht[16 + 16 + 1];
+	struct rcu_head			rcu;
 };
 
 struct route4_filter {
-	struct route4_filter	*next;
+	struct route4_filter __rcu	*next;
 	u32			id;
 	int			iif;
 
@@ -55,6 +56,8 @@ struct route4_filter {
 	struct tcf_exts		exts;
 	u32			handle;
 	struct route4_bucket	*bkt;
+	struct tcf_proto	*tp;
+	struct rcu_head		rcu;
 };
 
 #define ROUTE4_FAILURE ((struct route4_filter *)(-1L))
@@ -64,14 +67,13 @@ static inline int route4_fastmap_hash(u32 id, int iif)
 	return id & 0xF;
 }
 
+static DEFINE_SPINLOCK(fastmap_lock);
 static void
-route4_reset_fastmap(struct Qdisc *q, struct route4_head *head, u32 id)
+route4_reset_fastmap(struct route4_head *head)
 {
-	spinlock_t *root_lock = qdisc_root_sleeping_lock(q);
-
-	spin_lock_bh(root_lock);
+	spin_lock_bh(&fastmap_lock);
 	memset(head->fastmap, 0, sizeof(head->fastmap));
-	spin_unlock_bh(root_lock);
+	spin_unlock_bh(&fastmap_lock);
 }
 
 static void
@@ -80,9 +82,12 @@ route4_set_fastmap(struct route4_head *head, u32 id, int iif,
 {
 	int h = route4_fastmap_hash(id, iif);
 
+	/* fastmap updates must look atomic to aling id, iff, filter */
+	spin_lock_bh(&fastmap_lock);
 	head->fastmap[h].id = id;
 	head->fastmap[h].iif = iif;
 	head->fastmap[h].filter = f;
+	spin_unlock_bh(&fastmap_lock);
 }
 
 static inline int route4_hash_to(u32 id)
@@ -123,7 +128,7 @@ static inline int route4_hash_wild(void)
 static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 			   struct tcf_result *res)
 {
-	struct route4_head *head = tp->root;
+	struct route4_head *head = rcu_dereference_bh(tp->root);
 	struct dst_entry *dst;
 	struct route4_bucket *b;
 	struct route4_filter *f;
@@ -141,32 +146,43 @@ static int route4_classify(struct sk_buff *skb, const struct tcf_proto *tp,
 	iif = inet_iif(skb);
 
 	h = route4_fastmap_hash(id, iif);
+
+	spin_lock(&fastmap_lock);
 	if (id == head->fastmap[h].id &&
 	    iif == head->fastmap[h].iif &&
 	    (f = head->fastmap[h].filter) != NULL) {
-		if (f == ROUTE4_FAILURE)
+		if (f == ROUTE4_FAILURE) {
+			spin_unlock(&fastmap_lock);
 			goto failure;
+		}
 
 		*res = f->res;
+		spin_unlock(&fastmap_lock);
 		return 0;
 	}
+	spin_unlock(&fastmap_lock);
 
 	h = route4_hash_to(id);
 
 restart:
-	b = head->table[h];
+	b = rcu_dereference_bh(head->table[h]);
 	if (b) {
-		for (f = b->ht[route4_hash_from(id)]; f; f = f->next)
+		for (f = rcu_dereference_bh(b->ht[route4_hash_from(id)]);
+		     f;
+		     f = rcu_dereference_bh(f->next))
 			if (f->id == id)
 				ROUTE4_APPLY_RESULT();
 
-		for (f = b->ht[route4_hash_iif(iif)]; f; f = f->next)
+		for (f = rcu_dereference_bh(b->ht[route4_hash_iif(iif)]);
+		     f;
+		     f = rcu_dereference_bh(f->next))
 			if (f->iif == iif)
 				ROUTE4_APPLY_RESULT();
 
-		for (f = b->ht[route4_hash_wild()]; f; f = f->next)
+		for (f = rcu_dereference_bh(b->ht[route4_hash_wild()]);
+		     f;
+		     f = rcu_dereference_bh(f->next))
 			ROUTE4_APPLY_RESULT();
-
 	}
 	if (h < 256) {
 		h = 256;
@@ -213,7 +229,7 @@ static inline u32 from_hash(u32 id)
 
 static unsigned long route4_get(struct tcf_proto *tp, u32 handle)
 {
-	struct route4_head *head = tp->root;
+	struct route4_head *head = rtnl_dereference(tp->root);
 	struct route4_bucket *b;
 	struct route4_filter *f;
 	unsigned int h1, h2;
@@ -229,9 +245,11 @@ static unsigned long route4_get(struct tcf_proto *tp, u32 handle)
 	if (h2 > 32)
 		return 0;
 
-	b = head->table[h1];
+	b = rtnl_dereference(head->table[h1]);
 	if (b) {
-		for (f = b->ht[h2]; f; f = f->next)
+		for (f = rtnl_dereference(b->ht[h2]);
+		     f;
+		     f = rtnl_dereference(f->next))
 			if (f->handle == handle)
 				return (unsigned long)f;
 	}
@@ -248,8 +266,11 @@ static int route4_init(struct tcf_proto *tp)
 }
 
 static void
-route4_delete_filter(struct tcf_proto *tp, struct route4_filter *f)
+route4_delete_filter(struct rcu_head *head)
 {
+	struct route4_filter *f = container_of(head, struct route4_filter, rcu);
+	struct tcf_proto *tp = f->tp;
+
 	tcf_unbind_filter(tp, &f->res);
 	tcf_exts_destroy(tp, &f->exts);
 	kfree(f);
@@ -257,7 +278,7 @@ route4_delete_filter(struct tcf_proto *tp, struct route4_filter *f)
 
 static void route4_destroy(struct tcf_proto *tp)
 {
-	struct route4_head *head = tp->root;
+	struct route4_head *head = rtnl_dereference(tp->root);
 	int h1, h2;
 
 	if (head == NULL)
@@ -266,28 +287,35 @@ static void route4_destroy(struct tcf_proto *tp)
 	for (h1 = 0; h1 <= 256; h1++) {
 		struct route4_bucket *b;
 
-		b = head->table[h1];
+		b = rtnl_dereference(head->table[h1]);
 		if (b) {
 			for (h2 = 0; h2 <= 32; h2++) {
 				struct route4_filter *f;
 
-				while ((f = b->ht[h2]) != NULL) {
-					b->ht[h2] = f->next;
-					route4_delete_filter(tp, f);
+				while ((f = rtnl_dereference(b->ht[h2])) != NULL) {
+					struct route4_filter *next;
+
+					next = rtnl_dereference(f->next);
+					RCU_INIT_POINTER(b->ht[h2], next);
+					call_rcu(&f->rcu, route4_delete_filter);
 				}
 			}
-			kfree(b);
+			RCU_INIT_POINTER(head->table[h1], NULL);
+			kfree_rcu(b, rcu);
 		}
 	}
-	kfree(head);
+	RCU_INIT_POINTER(tp->root, NULL);
+	kfree_rcu(head, rcu);
 }
 
 static int route4_delete(struct tcf_proto *tp, unsigned long arg)
 {
-	struct route4_head *head = tp->root;
-	struct route4_filter **fp, *f = (struct route4_filter *)arg;
-	unsigned int h = 0;
+	struct route4_head *head = rtnl_dereference(tp->root);
+	struct route4_filter *f = (struct route4_filter *)arg;
+	struct route4_filter __rcu **fp;
+	struct route4_filter *nf;
 	struct route4_bucket *b;
+	unsigned int h = 0;
 	int i;
 
 	if (!head || !f)
@@ -296,27 +324,35 @@ static int route4_delete(struct tcf_proto *tp, unsigned long arg)
 	h = f->handle;
 	b = f->bkt;
 
-	for (fp = &b->ht[from_hash(h >> 16)]; *fp; fp = &(*fp)->next) {
-		if (*fp == f) {
-			tcf_tree_lock(tp);
-			*fp = f->next;
-			tcf_tree_unlock(tp);
+	fp = &b->ht[from_hash(h >> 16)];
+	for (nf = rtnl_dereference(*fp); nf;
+	     fp = &nf->next, nf = rtnl_dereference(*fp)) {
+		if (nf == f) {
+			/* unlink it */
+			RCU_INIT_POINTER(*fp, rtnl_dereference(f->next));
 
-			route4_reset_fastmap(tp->q, head, f->id);
-			route4_delete_filter(tp, f);
+			/* Remove any fastmap lookups that might ref filter
+			 * notice we unlink'd the filter so we can't get it
+			 * back in the fastmap.
+			 */
+			route4_reset_fastmap(head);
 
-			/* Strip tree */
+			/* Delete it */
+			call_rcu(&f->rcu, route4_delete_filter);
 
-			for (i = 0; i <= 32; i++)
-				if (b->ht[i])
+			/* Strip RTNL protected tree */
+			for (i = 0; i <= 32; i++) {
+				struct route4_filter *rt;
+
+				rt = rtnl_dereference(b->ht[i]);
+				if (rt)
 					return 0;
+			}
 
 			/* OK, session has no flows */
-			tcf_tree_lock(tp);
-			head->table[to_hash(h)] = NULL;
-			tcf_tree_unlock(tp);
+			RCU_INIT_POINTER(head->table[to_hash(h)], NULL);
+			kfree_rcu(b, rcu);
 
-			kfree(b);
 			return 0;
 		}
 	}
@@ -380,26 +416,25 @@ static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 	}
 
 	h1 = to_hash(nhandle);
-	b = head->table[h1];
+	b = rtnl_dereference(head->table[h1]);
 	if (!b) {
 		err = -ENOBUFS;
 		b = kzalloc(sizeof(struct route4_bucket), GFP_KERNEL);
 		if (b == NULL)
 			goto errout;
 
-		tcf_tree_lock(tp);
-		head->table[h1] = b;
-		tcf_tree_unlock(tp);
+		rcu_assign_pointer(head->table[h1], b);
 	} else {
 		unsigned int h2 = from_hash(nhandle >> 16);
 
 		err = -EEXIST;
-		for (fp = b->ht[h2]; fp; fp = fp->next)
+		for (fp = rtnl_dereference(b->ht[h2]);
+		     fp;
+		     fp = rtnl_dereference(fp->next))
 			if (fp->handle == f->handle)
 				goto errout;
 	}
 
-	tcf_tree_lock(tp);
 	if (tb[TCA_ROUTE4_TO])
 		f->id = to;
 
@@ -410,7 +445,7 @@ static int route4_set_parms(struct net *net, struct tcf_proto *tp,
 
 	f->handle = nhandle;
 	f->bkt = b;
-	tcf_tree_unlock(tp);
+	f->tp = tp;
 
 	if (tb[TCA_ROUTE4_CLASSID]) {
 		f->res.classid = nla_get_u32(tb[TCA_ROUTE4_CLASSID]);
@@ -431,14 +466,15 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
 		       struct nlattr **tca,
 		       unsigned long *arg, bool ovr)
 {
-	struct route4_head *head = tp->root;
-	struct route4_filter *f, *f1, **fp;
+	struct route4_head *head = rtnl_dereference(tp->root);
+	struct route4_filter __rcu **fp;
+	struct route4_filter *fold, *f1, *pfp, *f = NULL;
 	struct route4_bucket *b;
 	struct nlattr *opt = tca[TCA_OPTIONS];
 	struct nlattr *tb[TCA_ROUTE4_MAX + 1];
 	unsigned int h, th;
-	u32 old_handle = 0;
 	int err;
+	bool new = true;
 
 	if (opt == NULL)
 		return handle ? -EINVAL : 0;
@@ -447,70 +483,70 @@ static int route4_change(struct net *net, struct sk_buff *in_skb,
 	if (err < 0)
 		return err;
 
-	f = (struct route4_filter *)*arg;
-	if (f) {
-		if (f->handle != handle && handle)
+	fold = (struct route4_filter *)*arg;
+	if (fold && handle && fold->handle != handle)
 			return -EINVAL;
 
-		if (f->bkt)
-			old_handle = f->handle;
-
-		err = route4_set_parms(net, tp, base, f, handle, head, tb,
-			tca[TCA_RATE], 0, ovr);
-		if (err < 0)
-			return err;
-
-		goto reinsert;
-	}
-
 	err = -ENOBUFS;
 	if (head == NULL) {
 		head = kzalloc(sizeof(struct route4_head), GFP_KERNEL);
 		if (head == NULL)
 			goto errout;
-
-		tcf_tree_lock(tp);
-		tp->root = head;
-		tcf_tree_unlock(tp);
+		rcu_assign_pointer(tp->root, head);
 	}
 
 	f = kzalloc(sizeof(struct route4_filter), GFP_KERNEL);
-	if (f == NULL)
+	if (!f)
 		goto errout;
 
 	tcf_exts_init(&f->exts, TCA_ROUTE4_ACT, TCA_ROUTE4_POLICE);
+	if (fold) {
+		f->id = fold->id;
+		f->iif = fold->iif;
+		f->res = fold->res;
+		f->handle = fold->handle;
+
+		f->tp = fold->tp;
+		f->bkt = fold->bkt;
+		new = false;
+	}
+
 	err = route4_set_parms(net, tp, base, f, handle, head, tb,
-		tca[TCA_RATE], 1, ovr);
+			       tca[TCA_RATE], new, ovr);
 	if (err < 0)
 		goto errout;
 
-reinsert:
 	h = from_hash(f->handle >> 16);
-	for (fp = &f->bkt->ht[h]; (f1 = *fp) != NULL; fp = &f1->next)
+	fp = &f->bkt->ht[h];
+	for (pfp = rtnl_dereference(*fp);
+	     (f1 = rtnl_dereference(*fp)) != NULL;
+	     fp = &f1->next)
 		if (f->handle < f1->handle)
 			break;
 
-	f->next = f1;
-	tcf_tree_lock(tp);
-	*fp = f;
+	rcu_assign_pointer(f->next, f1);
+	rcu_assign_pointer(*fp, f);
 
-	if (old_handle && f->handle != old_handle) {
-		th = to_hash(old_handle);
-		h = from_hash(old_handle >> 16);
-		b = head->table[th];
+	if (fold && fold->handle && f->handle != fold->handle) {
+		th = to_hash(fold->handle);
+		h = from_hash(fold->handle >> 16);
+		b = rtnl_dereference(head->table[th]);
 		if (b) {
-			for (fp = &b->ht[h]; *fp; fp = &(*fp)->next) {
-				if (*fp == f) {
+			fp = &b->ht[h];
+			for (pfp = rtnl_dereference(*fp); pfp;
+			     fp = &pfp->next, pfp = rtnl_dereference(*fp)) {
+				if (pfp == f) {
 					*fp = f->next;
 					break;
 				}
 			}
 		}
 	}
-	tcf_tree_unlock(tp);
 
-	route4_reset_fastmap(tp->q, head, f->id);
+	route4_reset_fastmap(head);
 	*arg = (unsigned long)f;
+	if (fold)
+		call_rcu(&fold->rcu, route4_delete_filter);
 	return 0;
 
 errout:
@@ -520,7 +556,7 @@ errout:
 
 static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 {
-	struct route4_head *head = tp->root;
+	struct route4_head *head = rtnl_dereference(tp->root);
 	unsigned int h, h1;
 
 	if (head == NULL)
@@ -530,13 +566,15 @@ static void route4_walk(struct tcf_proto *tp, struct tcf_walker *arg)
 		return;
 
 	for (h = 0; h <= 256; h++) {
-		struct route4_bucket *b = head->table[h];
+		struct route4_bucket *b = rtnl_dereference(head->table[h]);
 
 		if (b) {
 			for (h1 = 0; h1 <= 32; h1++) {
 				struct route4_filter *f;
 
-				for (f = b->ht[h1]; f; f = f->next) {
+				for (f = rtnl_dereference(b->ht[h1]);
+				     f;
+				     f = rtnl_dereference(f->next)) {
 					if (arg->count < arg->skip) {
 						arg->count++;
 						continue;