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macvlan: no longer rely on RTNL in macvlan_fill_info()

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Add READ_ONCE()/WRITE_ONCE() annotations on vlan->mode, vlan->flags,
vlan->bc_queue_len_req and port->bc_cutoff.

Fill IFLA_MACVLAN_MACADDR_DATA nested attribute and compute
on the fly the precise number of elements we put in it,
to fill an accurate IFLA_MACVLAN_MACADDR_COUNT attribute
as some user space applications could depend on its value
and the attributes order.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20260701082214.2974946-3-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Eric Dumazet 2026-07-01 08:22:14 +00:00 committed by Paolo Abeni
parent ed37710d6c
commit 6d728e7e28
1 changed files with 48 additions and 23 deletions
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71
drivers/net/macvlan.c
View File

@ -171,7 +171,7 @@ static int macvlan_hash_add_source(struct macvlan_dev *vlan,
RCU_INIT_POINTER(entry->vlan, vlan);
h = &port->vlan_source_hash[macvlan_eth_hash(addr)];
hlist_add_head_rcu(&entry->hlist, h);
vlan->macaddr_count++;
WRITE_ONCE(vlan->macaddr_count, vlan->macaddr_count + 1);
return 0;
}
@ -402,7 +402,7 @@ static void macvlan_flush_sources(struct macvlan_port *port,
if (rcu_access_pointer(entry->vlan) == vlan)
macvlan_hash_del_source(entry);
vlan->macaddr_count = 0;
WRITE_ONCE(vlan->macaddr_count, 0);
}
static void macvlan_forward_source_one(struct sk_buff *skb,
@ -874,7 +874,7 @@ static void update_port_bc_cutoff(struct macvlan_dev *vlan, int cutoff)
if (vlan->port->bc_cutoff == cutoff)
return;
vlan->port->bc_cutoff = cutoff;
WRITE_ONCE(vlan->port->bc_cutoff, cutoff);
macvlan_recompute_bc_filter(vlan);
}
@ -1427,7 +1427,7 @@ static int macvlan_changelink_sources(struct macvlan_dev *vlan, u32 mode,
entry = macvlan_hash_lookup_source(vlan, addr);
if (entry) {
macvlan_hash_del_source(entry);
vlan->macaddr_count--;
WRITE_ONCE(vlan->macaddr_count, vlan->macaddr_count - 1);
}
} else if (mode == MACVLAN_MACADDR_FLUSH) {
macvlan_flush_sources(vlan->port, vlan);
@ -1653,7 +1653,8 @@ static int macvlan_changelink(struct net_device *dev,
}
if (data && data[IFLA_MACVLAN_BC_QUEUE_LEN]) {
vlan->bc_queue_len_req = nla_get_u32(data[IFLA_MACVLAN_BC_QUEUE_LEN]);
WRITE_ONCE(vlan->bc_queue_len_req,
nla_get_u32(data[IFLA_MACVLAN_BC_QUEUE_LEN]));
update_port_bc_queue_len(vlan->port);
}
@ -1676,10 +1677,12 @@ static int macvlan_changelink(struct net_device *dev,
static size_t macvlan_get_size_mac(const struct macvlan_dev *vlan)
{
if (vlan->macaddr_count == 0)
unsigned int macaddr_count = READ_ONCE(vlan->macaddr_count);
if (!macaddr_count)
return 0;
return nla_total_size(0) /* IFLA_MACVLAN_MACADDR_DATA */
+ vlan->macaddr_count * nla_total_size(sizeof(u8) * ETH_ALEN);
+ macaddr_count * nla_total_size(sizeof(u8) * ETH_ALEN);
}
static size_t macvlan_get_size(const struct net_device *dev)
@ -1702,53 +1705,75 @@ static int macvlan_fill_info_macaddr(struct sk_buff *skb,
const int i)
{
struct hlist_head *h = &vlan->port->vlan_source_hash[i];
struct macvlan_source_entry *entry;
const struct macvlan_source_entry *entry;
int cnt = 0;
hlist_for_each_entry_rcu(entry, h, hlist, lockdep_rtnl_is_held()) {
hlist_for_each_entry_rcu(entry, h, hlist) {
if (rcu_access_pointer(entry->vlan) != vlan)
continue;
if (nla_put(skb, IFLA_MACVLAN_MACADDR, ETH_ALEN, entry->addr))
return 1;
return -EMSGSIZE;
cnt++;
}
return 0;
return cnt;
}
static int macvlan_fill_info(struct sk_buff *skb,
const struct net_device *dev)
{
struct macvlan_dev *vlan = netdev_priv(dev);
const struct macvlan_dev *vlan = netdev_priv(dev);
struct macvlan_port *port = vlan->port;
int i;
struct nlattr *nest;
unsigned int macaddr_count = 0;
struct nlattr *nest, *attr;
int bc_cutoff, cnt, i;
if (nla_put_u32(skb, IFLA_MACVLAN_MODE, vlan->mode))
rcu_read_lock();
if (nla_put_u32(skb, IFLA_MACVLAN_MODE, READ_ONCE(vlan->mode)))
goto nla_put_failure;
if (nla_put_u16(skb, IFLA_MACVLAN_FLAGS, vlan->flags))
if (nla_put_u16(skb, IFLA_MACVLAN_FLAGS, READ_ONCE(vlan->flags)))
goto nla_put_failure;
if (nla_put_u32(skb, IFLA_MACVLAN_MACADDR_COUNT, vlan->macaddr_count))
attr = nla_reserve(skb, IFLA_MACVLAN_MACADDR_COUNT, sizeof(u32));
if (!attr)
goto nla_put_failure;
if (vlan->macaddr_count > 0) {
if (READ_ONCE(vlan->macaddr_count) > 0) {
nest = nla_nest_start_noflag(skb, IFLA_MACVLAN_MACADDR_DATA);
if (nest == NULL)
goto nla_put_failure;
for (i = 0; i < MACVLAN_HASH_SIZE; i++) {
if (macvlan_fill_info_macaddr(skb, vlan, i))
cnt = macvlan_fill_info_macaddr(skb, vlan, i);
if (cnt < 0)
goto nla_put_failure;
macaddr_count += cnt;
}
nla_nest_end(skb, nest);
if (!macaddr_count)
nla_nest_cancel(skb, nest);
else if (nla_nest_end_safe(skb, nest) < 0)
goto nla_put_failure;
}
if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN, vlan->bc_queue_len_req))
*(u32 *)nla_data(attr) = macaddr_count;
if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN,
READ_ONCE(vlan->bc_queue_len_req)))
goto nla_put_failure;
if (nla_put_u32(skb, IFLA_MACVLAN_BC_QUEUE_LEN_USED,
READ_ONCE(port->bc_queue_len_used)))
goto nla_put_failure;
if (port->bc_cutoff != 1 &&
nla_put_s32(skb, IFLA_MACVLAN_BC_CUTOFF, port->bc_cutoff))
bc_cutoff = READ_ONCE(port->bc_cutoff);
if (bc_cutoff != 1 &&
nla_put_s32(skb, IFLA_MACVLAN_BC_CUTOFF, bc_cutoff))
goto nla_put_failure;
rcu_read_unlock();
return 0;
nla_put_failure:
rcu_read_unlock();
return -EMSGSIZE;
}