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Message-ID: <20241104080437.103-7-gnaaman@drivenets.com>
Date: Mon, 4 Nov 2024 08:04:34 +0000
From: Gilad Naaman <gnaaman@...venets.com>
To: netdev@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Kuniyuki Iwashima <kuniyu@...zon.com>
Cc: Gilad Naaman <gnaaman@...venets.com>
Subject: [PATCH net-next v8 6/6] neighbour: Create netdev->neighbour association
Create a mapping between a netdev and its neighoburs,
allowing for much cheaper flushes.
Signed-off-by: Gilad Naaman <gnaaman@...venets.com>
---
.../networking/net_cachelines/net_device.rst | 1 +
include/linux/netdevice.h | 7 ++
include/net/neighbour.h | 9 +-
include/net/neighbour_tables.h | 12 +++
net/core/neighbour.c | 96 +++++++++++--------
5 files changed, 80 insertions(+), 45 deletions(-)
create mode 100644 include/net/neighbour_tables.h
diff --git a/Documentation/networking/net_cachelines/net_device.rst b/Documentation/networking/net_cachelines/net_device.rst
index ade50d4e67cf..15e31ece675f 100644
--- a/Documentation/networking/net_cachelines/net_device.rst
+++ b/Documentation/networking/net_cachelines/net_device.rst
@@ -188,4 +188,5 @@ u64 max_pacing_offload_horizon
struct_napi_config* napi_config
unsigned_long gro_flush_timeout
u32 napi_defer_hard_irqs
+struct hlist_head neighbours[2]
=================================== =========================== =================== =================== ===================================================================================
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 3c552b648b27..df4483598628 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -52,6 +52,7 @@
#include <net/net_trackers.h>
#include <net/net_debug.h>
#include <net/dropreason-core.h>
+#include <net/neighbour_tables.h>
struct netpoll_info;
struct device;
@@ -2032,6 +2033,9 @@ enum netdev_reg_state {
* @napi_defer_hard_irqs: If not zero, provides a counter that would
* allow to avoid NIC hard IRQ, on busy queues.
*
+ * @neighbours: List heads pointing to this device's neighbours'
+ * dev_list, one per address-family.
+ *
* FIXME: cleanup struct net_device such that network protocol info
* moves out.
*/
@@ -2440,6 +2444,9 @@ struct net_device {
*/
struct net_shaper_hierarchy *net_shaper_hierarchy;
#endif
+
+ struct hlist_head neighbours[NEIGH_NR_TABLES];
+
u8 priv[] ____cacheline_aligned
__counted_by(priv_len);
} ____cacheline_aligned;
diff --git a/include/net/neighbour.h b/include/net/neighbour.h
index 0244fbd22a1f..bb345ce8bbf8 100644
--- a/include/net/neighbour.h
+++ b/include/net/neighbour.h
@@ -29,6 +29,7 @@
#include <linux/sysctl.h>
#include <linux/workqueue.h>
#include <net/rtnetlink.h>
+#include <net/neighbour_tables.h>
/*
* NUD stands for "neighbor unreachability detection"
@@ -136,6 +137,7 @@ struct neigh_statistics {
struct neighbour {
struct hlist_node hash;
+ struct hlist_node dev_list;
struct neigh_table *tbl;
struct neigh_parms *parms;
unsigned long confirmed;
@@ -236,13 +238,6 @@ struct neigh_table {
struct pneigh_entry **phash_buckets;
};
-enum {
- NEIGH_ARP_TABLE = 0,
- NEIGH_ND_TABLE = 1,
- NEIGH_NR_TABLES,
- NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
-};
-
static inline int neigh_parms_family(struct neigh_parms *p)
{
return p->tbl->family;
diff --git a/include/net/neighbour_tables.h b/include/net/neighbour_tables.h
new file mode 100644
index 000000000000..bcffbe8f7601
--- /dev/null
+++ b/include/net/neighbour_tables.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _NET_NEIGHBOUR_TABLES_H
+#define _NET_NEIGHBOUR_TABLES_H
+
+enum {
+ NEIGH_ARP_TABLE = 0,
+ NEIGH_ND_TABLE = 1,
+ NEIGH_NR_TABLES,
+ NEIGH_LINK_TABLE = NEIGH_NR_TABLES /* Pseudo table for neigh_xmit */
+};
+
+#endif
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index a379b80a22c5..6135ae2001d6 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -60,6 +60,25 @@ static int pneigh_ifdown_and_unlock(struct neigh_table *tbl,
static const struct seq_operations neigh_stat_seq_ops;
#endif
+static struct hlist_head *neigh_get_dev_table(struct net_device *dev, int family)
+{
+ int i;
+
+ switch (family) {
+ default:
+ DEBUG_NET_WARN_ON_ONCE(1);
+ fallthrough; /* to avoid panic by null-ptr-deref */
+ case AF_INET:
+ i = NEIGH_ARP_TABLE;
+ break;
+ case AF_INET6:
+ i = NEIGH_ND_TABLE;
+ break;
+ }
+
+ return &dev->neighbours[i];
+}
+
/*
Neighbour hash table buckets are protected with rwlock tbl->lock.
@@ -211,6 +230,7 @@ bool neigh_remove_one(struct neighbour *n)
write_lock(&n->lock);
if (refcount_read(&n->refcnt) == 1) {
hlist_del_rcu(&n->hash);
+ hlist_del_rcu(&n->dev_list);
neigh_mark_dead(n);
retval = true;
}
@@ -351,48 +371,42 @@ static void pneigh_queue_purge(struct sk_buff_head *list, struct net *net,
static void neigh_flush_dev(struct neigh_table *tbl, struct net_device *dev,
bool skip_perm)
{
- int i;
- struct neigh_hash_table *nht;
-
- nht = rcu_dereference_protected(tbl->nht,
- lockdep_is_held(&tbl->lock));
+ struct hlist_head *dev_head;
+ struct hlist_node *tmp;
+ struct neighbour *n;
- for (i = 0; i < (1 << nht->hash_shift); i++) {
- struct hlist_node *tmp;
- struct neighbour *n;
+ dev_head = neigh_get_dev_table(dev, tbl->family);
- neigh_for_each_in_bucket_safe(n, tmp, &nht->hash_heads[i]) {
- if (dev && n->dev != dev)
- continue;
- if (skip_perm && n->nud_state & NUD_PERMANENT)
- continue;
+ hlist_for_each_entry_safe(n, tmp, dev_head, dev_list) {
+ if (skip_perm && n->nud_state & NUD_PERMANENT)
+ continue;
- hlist_del_rcu(&n->hash);
- write_lock(&n->lock);
- neigh_del_timer(n);
- neigh_mark_dead(n);
- if (refcount_read(&n->refcnt) != 1) {
- /* The most unpleasant situation.
- We must destroy neighbour entry,
- but someone still uses it.
-
- The destroy will be delayed until
- the last user releases us, but
- we must kill timers etc. and move
- it to safe state.
- */
- __skb_queue_purge(&n->arp_queue);
- n->arp_queue_len_bytes = 0;
- WRITE_ONCE(n->output, neigh_blackhole);
- if (n->nud_state & NUD_VALID)
- n->nud_state = NUD_NOARP;
- else
- n->nud_state = NUD_NONE;
- neigh_dbg(2, "neigh %p is stray\n", n);
- }
- write_unlock(&n->lock);
- neigh_cleanup_and_release(n);
+ hlist_del_rcu(&n->hash);
+ hlist_del_rcu(&n->dev_list);
+ write_lock(&n->lock);
+ neigh_del_timer(n);
+ neigh_mark_dead(n);
+ if (refcount_read(&n->refcnt) != 1) {
+ /* The most unpleasant situation.
+ * We must destroy neighbour entry,
+ * but someone still uses it.
+ *
+ * The destroy will be delayed until
+ * the last user releases us, but
+ * we must kill timers etc. and move
+ * it to safe state.
+ */
+ __skb_queue_purge(&n->arp_queue);
+ n->arp_queue_len_bytes = 0;
+ WRITE_ONCE(n->output, neigh_blackhole);
+ if (n->nud_state & NUD_VALID)
+ n->nud_state = NUD_NOARP;
+ else
+ n->nud_state = NUD_NONE;
+ neigh_dbg(2, "neigh %p is stray\n", n);
}
+ write_unlock(&n->lock);
+ neigh_cleanup_and_release(n);
}
}
@@ -655,6 +669,10 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey,
if (want_ref)
neigh_hold(n);
hlist_add_head_rcu(&n->hash, &nht->hash_heads[hash_val]);
+
+ hlist_add_head_rcu(&n->dev_list,
+ neigh_get_dev_table(dev, tbl->family));
+
write_unlock_bh(&tbl->lock);
neigh_dbg(2, "neigh %p is created\n", n);
rc = n;
@@ -935,6 +953,7 @@ static void neigh_periodic_work(struct work_struct *work)
!time_in_range_open(jiffies, n->used,
n->used + NEIGH_VAR(n->parms, GC_STALETIME)))) {
hlist_del_rcu(&n->hash);
+ hlist_del_rcu(&n->dev_list);
neigh_mark_dead(n);
write_unlock(&n->lock);
neigh_cleanup_and_release(n);
@@ -3054,6 +3073,7 @@ void __neigh_for_each_release(struct neigh_table *tbl,
release = cb(n);
if (release) {
hlist_del_rcu(&n->hash);
+ hlist_del_rcu(&n->dev_list);
neigh_mark_dead(n);
}
write_unlock(&n->lock);
--
2.34.1
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