diff mbox series

[net-next,v5,4/6] Convert neighbour iteration to use hlist+macro

Message ID 20241017070445.4013745-5-gnaaman@drivenets.com (mailing list archive)
State Changes Requested
Delegated to: Netdev Maintainers
Headers show
Series Improve neigh_flush_dev performance | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for net-next, async
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit fail Errors and warnings before: 18 this patch: 19
netdev/build_tools success Errors and warnings before: 0 (+0) this patch: 0 (+0)
netdev/cc_maintainers success CCed 5 of 5 maintainers
netdev/build_clang fail Errors and warnings before: 36 this patch: 38
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn fail Errors and warnings before: 2628 this patch: 2629
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 109 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Gilad Naaman Oct. 17, 2024, 7:04 a.m. UTC 
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    | 34 +++++++++++++---------------------
 2 files changed, 16 insertions(+), 25 deletions(-)

Comments

Simon Horman Oct. 18, 2024, 11:42 a.m. UTC | #1 
On Thu, Oct 17, 2024 at 07:04:39AM +0000, Gilad Naaman wrote:
> 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>

...

> diff --git a/net/core/neighbour.c b/net/core/neighbour.c

...

> @@ -621,11 +620,9 @@ 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);
>  

Hi Gilad,

With this change next is now set but otherwise unused in this function.
Probably it can be removed.

Flagged by W=1 x86_64 allmodconfig builds with gcc-14 and clang-18.

...
diff mbox series

Patch

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 14f08a2e4f74..96528a6cd74b 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -278,6 +278,8 @@  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_first_entry(bucket) \
 	hlist_entry_safe((bucket)->first, struct neighbour, hash)
 
@@ -309,12 +311,9 @@  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 e4e31d2ca2ea..a1dd419655a1 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;
@@ -621,11 +620,9 @@  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);
 
@@ -726,11 +723,7 @@  ___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);
@@ -982,10 +975,11 @@  static void neigh_connect(struct neighbour *neigh)
 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 neigh_hash_table *nht;
 	struct neighbour __rcu **np;
+	struct hlist_node *tmp;
+	struct neighbour *n;
 	unsigned int i;
-	struct neigh_hash_table *nht;
 
 	NEIGH_CACHE_STAT_INC(tbl, periodic_gc_runs);
 
@@ -1012,8 +1006,7 @@  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);
@@ -2763,9 +2756,8 @@  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) ||
@@ -3124,18 +3116,18 @@  static int neigh_get(struct sk_buff *in_skb, struct nlmsghdr *nlh,
 void __neigh_for_each_release(struct neigh_table *tbl,
 			      int (*cb)(struct neighbour *))
 {
-	int chain;
 	struct neigh_hash_table *nht;
+	int chain;
 
 	nht = rcu_dereference_protected(tbl->nht,
 					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);