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Date: Fri, 25 Nov 2022 17:56:09 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>,
Kurt Kanzenbach <kurt@...utronix.de>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: [PATCH v4 net-next 7/8] hsr: Use a single struct for self_node.
self_node_db is a list_head with one entry of struct hsr_node. The
purpose is to hold the two MAC addresses of the node itself.
It is convenient to recycle the structure. However having a list_head
and fetching always the first entry is not really optimal.
Created a new data strucure contaning the two MAC addresses named
hsr_self_node. Access that structure like an RCU protected pointer so
it can be replaced on the fly without blocking the reader.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
net/hsr/hsr_device.c | 1 -
net/hsr/hsr_framereg.c | 63 +++++++++++++++++++-----------------------
net/hsr/hsr_main.h | 8 +++++-
3 files changed, 35 insertions(+), 37 deletions(-)
diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
index b1e86a7265b32..5a236aae2366f 100644
--- a/net/hsr/hsr_device.c
+++ b/net/hsr/hsr_device.c
@@ -490,7 +490,6 @@ int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
hsr = netdev_priv(hsr_dev);
INIT_LIST_HEAD(&hsr->ports);
INIT_LIST_HEAD(&hsr->node_db);
- INIT_LIST_HEAD(&hsr->self_node_db);
spin_lock_init(&hsr->list_lock);
eth_hw_addr_set(hsr_dev, slave[0]->dev_addr);
diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index 39a6088080e93..00db74d96583d 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -38,21 +38,22 @@ static bool seq_nr_after(u16 a, u16 b)
bool hsr_addr_is_self(struct hsr_priv *hsr, unsigned char *addr)
{
- struct hsr_node *node;
+ struct hsr_self_node *sn;
+ bool ret = false;
- node = list_first_or_null_rcu(&hsr->self_node_db, struct hsr_node,
- mac_list);
- if (!node) {
+ rcu_read_lock();
+ sn = rcu_dereference(hsr->self_node);
+ if (!sn) {
WARN_ONCE(1, "HSR: No self node\n");
- return false;
+ goto out;
}
- if (ether_addr_equal(addr, node->macaddress_A))
- return true;
- if (ether_addr_equal(addr, node->macaddress_B))
- return true;
-
- return false;
+ if (ether_addr_equal(addr, sn->macaddress_A) ||
+ ether_addr_equal(addr, sn->macaddress_B))
+ ret = true;
+out:
+ rcu_read_unlock();
+ return ret;
}
/* Search for mac entry. Caller must hold rcu read lock.
@@ -70,50 +71,42 @@ static struct hsr_node *find_node_by_addr_A(struct list_head *node_db,
return NULL;
}
-/* Helper for device init; the self_node_db is used in hsr_rcv() to recognize
+/* Helper for device init; the self_node is used in hsr_rcv() to recognize
* frames from self that's been looped over the HSR ring.
*/
int hsr_create_self_node(struct hsr_priv *hsr,
const unsigned char addr_a[ETH_ALEN],
const unsigned char addr_b[ETH_ALEN])
{
- struct list_head *self_node_db = &hsr->self_node_db;
- struct hsr_node *node, *oldnode;
+ struct hsr_self_node *sn, *old;
- node = kmalloc(sizeof(*node), GFP_KERNEL);
- if (!node)
+ sn = kmalloc(sizeof(*sn), GFP_KERNEL);
+ if (!sn)
return -ENOMEM;
- ether_addr_copy(node->macaddress_A, addr_a);
- ether_addr_copy(node->macaddress_B, addr_b);
+ ether_addr_copy(sn->macaddress_A, addr_a);
+ ether_addr_copy(sn->macaddress_B, addr_b);
spin_lock_bh(&hsr->list_lock);
- oldnode = list_first_or_null_rcu(self_node_db,
- struct hsr_node, mac_list);
- if (oldnode) {
- list_replace_rcu(&oldnode->mac_list, &node->mac_list);
- spin_unlock_bh(&hsr->list_lock);
- kfree_rcu(oldnode, rcu_head);
- } else {
- list_add_tail_rcu(&node->mac_list, self_node_db);
- spin_unlock_bh(&hsr->list_lock);
- }
+ old = rcu_replace_pointer(hsr->self_node, sn,
+ lockdep_is_held(&hsr->list_lock));
+ spin_unlock_bh(&hsr->list_lock);
+ if (old)
+ kfree_rcu(old, rcu_head);
return 0;
}
void hsr_del_self_node(struct hsr_priv *hsr)
{
- struct list_head *self_node_db = &hsr->self_node_db;
- struct hsr_node *node;
+ struct hsr_self_node *old;
spin_lock_bh(&hsr->list_lock);
- node = list_first_or_null_rcu(self_node_db, struct hsr_node, mac_list);
- if (node) {
- list_del_rcu(&node->mac_list);
- kfree_rcu(node, rcu_head);
- }
+ old = rcu_replace_pointer(hsr->self_node, NULL,
+ lockdep_is_held(&hsr->list_lock));
spin_unlock_bh(&hsr->list_lock);
+ if (old)
+ kfree_rcu(old, rcu_head);
}
void hsr_del_nodes(struct list_head *node_db)
diff --git a/net/hsr/hsr_main.h b/net/hsr/hsr_main.h
index 16ae9fb09ccd2..ea9aa5130ad6d 100644
--- a/net/hsr/hsr_main.h
+++ b/net/hsr/hsr_main.h
@@ -182,11 +182,17 @@ struct hsr_proto_ops {
void (*update_san_info)(struct hsr_node *node, bool is_sup);
};
+struct hsr_self_node {
+ unsigned char macaddress_A[ETH_ALEN];
+ unsigned char macaddress_B[ETH_ALEN];
+ struct rcu_head rcu_head;
+};
+
struct hsr_priv {
struct rcu_head rcu_head;
struct list_head ports;
struct list_head node_db; /* Known HSR nodes */
- struct list_head self_node_db; /* MACs of slaves */
+ struct hsr_self_node *self_node; /* MACs of slaves */
struct timer_list announce_timer; /* Supervision frame dispatch */
struct timer_list prune_timer;
int announce_count;
--
2.38.1
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