[PATCH net-next v4 4/6] Convert neighbour iteration to use hlist+macro

[Gilad Naaman <gnaaman@drivenets.com>]

Remove all usage of the bare neighbour::next pointer,
replacing them with neighbour::hash and its for_each macro.

Signed-off-by: Gilad Naaman <gnaaman@drivenets.com>
---
 include/net/neighbour.h |  7 +++----
 net/core/neighbour.c    | 29 +++++++++++------------------
 2 files changed, 14 insertions(+), 22 deletions(-)

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 7dc0d4d6a4a8..c0c35a15d2ad 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -279,6 +279,8 @@ static inline void *neighbour_priv(const struct neighbour *n)
 extern const struct nla_policy nda_policy[];
 
 #define neigh_for_each(pos, head) hlist_for_each_entry(pos, head, hash)
+#define neigh_for_each_safe(pos, tmp, head) hlist_for_each_entry_safe(pos, tmp, head, hash)
+
 #define neigh_hlist_entry(n) hlist_entry_safe(n, struct neighbour, hash)
 #define neigh_first_rcu(bucket) \
 	neigh_hlist_entry(rcu_dereference(hlist_first_rcu(bucket)))
@@ -312,12 +314,9 @@ static inline struct neighbour *___neigh_lookup_noref(
 	u32 hash_val;
 
 	hash_val = hash(pkey, dev, nht->hash_rnd) >> (32 - nht->hash_shift);
-	for (n = rcu_dereference(nht->hash_buckets[hash_val]);
-	     n != NULL;
-	     n = rcu_dereference(n->next)) {
+	neigh_for_each(n, &nht->hash_heads[hash_val])
 		if (n->dev == dev && key_eq(n, pkey))
 			return n;
-	}
 
 	return NULL;
 }
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 4bdf7649ca57..cca524a55c97 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -391,8 +391,7 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
 		struct neighbour *n;
 		struct neighbour __rcu **np = &nht->hash_buckets[i];
 
-		while ((n = rcu_dereference_protected(*np,
-					lockdep_is_held(&tbl->lock))) != NULL) {
+		neigh_for_each(n, &nht->hash_heads[i]) {
 			if (dev && n->dev != dev) {
 				np = &n->next;
 				continue;
@@ -427,6 +426,7 @@ static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
 					n->nud_state = NUD_NONE;
 				neigh_dbg(2, "neigh %p is stray\n", n);
 			}
+			np = &n->next;
 			write_unlock(&n->lock);
 			neigh_cleanup_and_release(n);
 		}
@@ -614,11 +614,9 @@ static struct neigh_hash_table *neigh_hash_grow(struct neigh_table *tbl,
 
 	for (i = 0; i < (1 << old_nht->hash_shift); i++) {
 		struct neighbour *n, *next;
+		struct hlist_node *tmp;
 
-		for (n = rcu_dereference_protected(old_nht->hash_buckets[i],
-						   lockdep_is_held(&tbl->lock));
-		     n != NULL;
-		     n = next) {
+		neigh_for_each_safe(n, tmp, &old_nht->hash_heads[i]) {
 			hash = tbl->hash(n->primary_key, n->dev,
 					 new_nht->hash_rnd);
 
@@ -719,11 +717,7 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey,
 		goto out_tbl_unlock;
 	}
 
-	for (n1 = rcu_dereference_protected(nht->hash_buckets[hash_val],
-					    lockdep_is_held(&tbl->lock));
-	     n1 != NULL;
-	     n1 = rcu_dereference_protected(n1->next,
-			lockdep_is_held(&tbl->lock))) {
+	neigh_for_each(n1, &nht->hash_heads[hash_val]) {
 		if (dev == n1->dev && !memcmp(n1->primary_key, n->primary_key, key_len)) {
 			if (want_ref)
 				neigh_hold(n1);
@@ -976,6 +970,7 @@ static void neigh_periodic_work(struct work_struct *work)
 {
 	struct neigh_table *tbl = container_of(work, struct neigh_table, gc_work.work);
 	struct neighbour *n;
+	struct hlist_node *tmp;
 	struct neighbour __rcu **np;
 	unsigned int i;
 	struct neigh_hash_table *nht;
@@ -1005,8 +1000,7 @@ static void neigh_periodic_work(struct work_struct *work)
 	for (i = 0 ; i < (1 << nht->hash_shift); i++) {
 		np = &nht->hash_buckets[i];
 
-		while ((n = rcu_dereference_protected(*np,
-				lockdep_is_held(&tbl->lock))) != NULL) {
+		neigh_for_each_safe(n, tmp, &nht->hash_heads[i]) {
 			unsigned int state;
 
 			write_lock(&n->lock);
@@ -2756,9 +2750,8 @@ static int neigh_dump_table(struct neigh_table *tbl, struct sk_buff *skb,
 	for (h = s_h; h < (1 << nht->hash_shift); h++) {
 		if (h > s_h)
 			s_idx = 0;
-		for (n = rcu_dereference(nht->hash_buckets[h]), idx = 0;
-		     n != NULL;
-		     n = rcu_dereference(n->next)) {
+		idx = 0;
+		neigh_for_each(n, &nht->hash_heads[h]) {
 			if (idx < s_idx || !net_eq(dev_net(n->dev), net))
 				goto next;
 			if (neigh_ifindex_filtered(n->dev, filter->dev_idx) ||
@@ -3124,11 +3117,11 @@ void __neigh_for_each_release(struct neigh_table *tbl,
 					lockdep_is_held(&tbl->lock));
 	for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
 		struct neighbour *n;
+		struct hlist_node *tmp;
 		struct neighbour __rcu **np;
 
 		np = &nht->hash_buckets[chain];
-		while ((n = rcu_dereference_protected(*np,
-					lockdep_is_held(&tbl->lock))) != NULL) {
+		neigh_for_each_safe(n, tmp, &nht->hash_heads[chain]) {
 			int release;
 
 			write_lock(&n->lock);
-- 
2.46.0