diff mbox series

[net-next,v8,4/6] neighbour: Convert iteration to use hlist+macro

Message ID 20241104080437.103-5-gnaaman@drivenets.com (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series Improve neigh_flush_dev performance | expand

Checks

Context Check Description
netdev/series_format warning Series does not have a cover letter
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 success Errors and warnings before: 16 this patch: 16
netdev/build_tools success Errors and warnings before: 2 (+0) this patch: 2 (+0)
netdev/cc_maintainers warning 1 maintainers not CCed: horms@kernel.org
netdev/build_clang success Errors and warnings before: 27 this patch: 27
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 success Errors and warnings before: 2625 this patch: 2625
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 125 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
netdev/contest success net-next-2024-11-06--12-00 (tests: 782)

Commit Message

Gilad Naaman Nov. 4, 2024, 8:04 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 |  5 +----
 net/core/neighbour.c    | 47 ++++++++++++++++-------------------------
 2 files changed, 19 insertions(+), 33 deletions(-)

Comments

Kuniyuki Iwashima Nov. 6, 2024, 8:40 p.m. UTC | #1 
From: Gilad Naaman <gnaaman@drivenets.com>
Date: Mon,  4 Nov 2024 08:04:32 +0000
> 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>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Kuniyuki Iwashima Nov. 6, 2024, 11:07 p.m. UTC | #2 
From: Gilad Naaman <gnaaman@drivenets.com>
Date: Mon,  4 Nov 2024 08:04:32 +0000
> diff --git a/include/net/neighbour.h b/include/net/neighbour.h
> index 69aaacd1419f..68b1970d9045 100644
> --- a/include/net/neighbour.h
> +++ b/include/net/neighbour.h
> @@ -309,12 +309,9 @@ 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_in_bucket(n, &nht->hash_heads[hash_val])

Sorry, I missed this part needs to be _rcu version.

You can keep my Reviewed-by tag in v9.


>  		if (n->dev == dev && key_eq(n, pkey))
>  			return n;
> -	}
>  
>  	return NULL;
>  }
Gilad Naaman Nov. 7, 2024, 5:39 a.m. UTC | #3 
> > diff --git a/include/net/neighbour.h b/include/net/neighbour.h
> > index 69aaacd1419f..68b1970d9045 100644
> > --- a/include/net/neighbour.h
> > +++ b/include/net/neighbour.h
> > @@ -309,12 +309,9 @@ 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_in_bucket(n, &nht->hash_heads[hash_val])
> 
> Sorry, I missed this part needs to be _rcu version.
> 
> You can keep my Reviewed-by tag in v9.
> 

No problem at all, will do.

Is it possible that the `_rcu` version will also be needed in `neigh_dump_table`?
It is called from an `rcu_read_lock`ed section, and it doesn't hold the table-lock.
Kuniyuki Iwashima Nov. 7, 2024, 5:48 a.m. UTC | #4 
From: Gilad Naaman <gnaaman@drivenets.com>
Date: Thu,  7 Nov 2024 05:39:46 +0000
> > > diff --git a/include/net/neighbour.h b/include/net/neighbour.h
> > > index 69aaacd1419f..68b1970d9045 100644
> > > --- a/include/net/neighbour.h
> > > +++ b/include/net/neighbour.h
> > > @@ -309,12 +309,9 @@ 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_in_bucket(n, &nht->hash_heads[hash_val])
> > 
> > Sorry, I missed this part needs to be _rcu version.
> > 
> > You can keep my Reviewed-by tag in v9.
> > 
> 
> No problem at all, will do.
> 
> Is it possible that the `_rcu` version will also be needed in `neigh_dump_table`?
> It is called from an `rcu_read_lock`ed section, and it doesn't hold the table-lock.

Right, there also should use _rcu one.
diff mbox series

Patch

diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 69aaacd1419f..68b1970d9045 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -309,12 +309,9 @@  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_in_bucket(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 3485d6b3ba99..f7119380d983 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -387,11 +387,11 @@  static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
 					lockdep_is_held(&tbl->lock));
 
 	for (i = 0; i < (1 << nht->hash_shift); i++) {
-		struct neighbour *n;
 		struct neighbour __rcu **np = &nht->hash_buckets[i];
+		struct hlist_node *tmp;
+		struct neighbour *n;
 
-		while ((n = rcu_dereference_protected(*np,
-					lockdep_is_held(&tbl->lock))) != NULL) {
+		neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[i]) {
 			if (dev && n->dev != dev) {
 				np = &n->next;
 				continue;
@@ -587,18 +587,14 @@  static struct neigh_hash_table *neigh_hash_grow(struct neigh_table *tbl,
 		return old_nht;
 
 	for (i = 0; i < (1 << old_nht->hash_shift); i++) {
-		struct neighbour *n, *next;
+		struct hlist_node *tmp;
+		struct neighbour *n;
 
-		for (n = rcu_dereference_protected(old_nht->hash_buckets[i],
-						   lockdep_is_held(&tbl->lock));
-		     n != NULL;
-		     n = next) {
+		neigh_for_each_in_bucket_safe(n, tmp, &old_nht->hash_heads[i]) {
 			hash = tbl->hash(n->primary_key, n->dev,
 					 new_nht->hash_rnd);
 
 			hash >>= (32 - new_nht->hash_shift);
-			next = rcu_dereference_protected(n->next,
-						lockdep_is_held(&tbl->lock));
 
 			rcu_assign_pointer(n->next,
 					   rcu_dereference_protected(
@@ -693,11 +689,7 @@  ___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_in_bucket(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);
@@ -949,10 +941,11 @@  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);
 
@@ -979,8 +972,7 @@  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_in_bucket_safe(n, tmp, &nht->hash_heads[i]) {
 			unsigned int state;
 
 			write_lock(&n->lock);
@@ -2730,9 +2722,8 @@  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_in_bucket(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) ||
@@ -3099,9 +3090,7 @@  void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void
 	for (chain = 0; chain < (1 << nht->hash_shift); chain++) {
 		struct neighbour *n;
 
-		for (n = rcu_dereference(nht->hash_buckets[chain]);
-		     n != NULL;
-		     n = rcu_dereference(n->next))
+		neigh_for_each_in_bucket(n, &nht->hash_heads[chain])
 			cb(n, cookie);
 	}
 	read_unlock_bh(&tbl->lock);
@@ -3113,18 +3102,18 @@  EXPORT_SYMBOL(neigh_for_each);
 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 neighbour __rcu **np;
+		struct hlist_node *tmp;
+		struct neighbour *n;
 
 		np = &nht->hash_buckets[chain];
-		while ((n = rcu_dereference_protected(*np,
-					lockdep_is_held(&tbl->lock))) != NULL) {
+		neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[chain]) {
 			int release;
 
 			write_lock(&n->lock);