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mpls: Convert mpls_dump_routes() to RCU.

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mpls_dump_routes() sets fib_dump_filter.rtnl_held to true and
calls __dev_get_by_index() in mpls_valid_fib_dump_req().

This is the only RTNL dependant in mpls_dump_routes().

Also, synchronize_rcu() in resize_platform_label_table()
guarantees that net->mpls.platform_label is alive under RCU.

Let's convert mpls_dump_routes() to RCU and use dev_get_by_index_rcu().

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Link: https://patch.msgid.link/20251029173344.2934622-11-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima
2025-10-29 17:33:02 +00:00
committed by Jakub Kicinski
parent 3a49629335
commit dde1b38e87
1 changed files with 16 additions and 10 deletions
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26
net/mpls/af_mpls.c
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@@ -2153,7 +2153,7 @@ static int mpls_valid_fib_dump_req(struct net *net, const struct nlmsghdr *nlh,
if (i == RTA_OIF) {
ifindex = nla_get_u32(tb[i]);
filter->dev = __dev_get_by_index(net, ifindex);
filter->dev = dev_get_by_index_rcu(net, ifindex);
if (!filter->dev)
return -ENODEV;
filter->filter_set = 1;
@@ -2191,20 +2191,19 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
struct net *net = sock_net(skb->sk);
struct mpls_route __rcu **platform_label;
struct fib_dump_filter filter = {
.rtnl_held = true,
.rtnl_held = false,
};
unsigned int flags = NLM_F_MULTI;
size_t platform_labels;
unsigned int index;
int err;
ASSERT_RTNL();
rcu_read_lock();
if (cb->strict_check) {
int err;
err = mpls_valid_fib_dump_req(net, nlh, &filter, cb);
if (err < 0)
return err;
goto err;
/* for MPLS, there is only 1 table with fixed type and flags.
* If either are set in the filter then return nothing.
@@ -2212,14 +2211,14 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
if ((filter.table_id && filter.table_id != RT_TABLE_MAIN) ||
(filter.rt_type && filter.rt_type != RTN_UNICAST) ||
filter.flags)
return skb->len;
goto unlock;
}
index = cb->args[0];
if (index < MPLS_LABEL_FIRST_UNRESERVED)
index = MPLS_LABEL_FIRST_UNRESERVED;
platform_label = rtnl_dereference(net->mpls.platform_label);
platform_label = rcu_dereference(net->mpls.platform_label);
platform_labels = net->mpls.platform_labels;
if (filter.filter_set)
@@ -2228,7 +2227,7 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
for (; index < platform_labels; index++) {
struct mpls_route *rt;
rt = rtnl_dereference(platform_label[index]);
rt = rcu_dereference(platform_label[index]);
if (!rt)
continue;
@@ -2243,7 +2242,13 @@ static int mpls_dump_routes(struct sk_buff *skb, struct netlink_callback *cb)
}
cb->args[0] = index;
unlock:
rcu_read_unlock();
return skb->len;
err:
rcu_read_unlock();
return err;
}
static inline size_t lfib_nlmsg_size(struct mpls_route *rt)
@@ -2767,7 +2772,8 @@ static struct rtnl_af_ops mpls_af_ops __read_mostly = {
static const struct rtnl_msg_handler mpls_rtnl_msg_handlers[] __initdata_or_module = {
{THIS_MODULE, PF_MPLS, RTM_NEWROUTE, mpls_rtm_newroute, NULL, 0},
{THIS_MODULE, PF_MPLS, RTM_DELROUTE, mpls_rtm_delroute, NULL, 0},
{THIS_MODULE, PF_MPLS, RTM_GETROUTE, mpls_getroute, mpls_dump_routes, 0},
{THIS_MODULE, PF_MPLS, RTM_GETROUTE, mpls_getroute, mpls_dump_routes,
RTNL_FLAG_DUMP_UNLOCKED},
{THIS_MODULE, PF_MPLS, RTM_GETNETCONF,
mpls_netconf_get_devconf, mpls_netconf_dump_devconf,
RTNL_FLAG_DUMP_UNLOCKED},