+++ /dev/null
-From f55180327012f0f847d9cd05ce4662c3e3d56e38 Mon Sep 17 00:00:00 2001
-From: Sasha Levin <sashal@kernel.org>
-Date: Thu, 6 Jun 2024 12:29:05 -0700
-Subject: rtnetlink: move rtnl_lock handling out of af_netlink
-
-From: Jakub Kicinski <kuba@kernel.org>
-
-[ Upstream commit 5380d64f8d766576ac5c0f627418b2d0e1d2641f ]
-
-Now that we have an intermediate layer of code for handling
-rtnl-level netlink dump quirks, we can move the rtnl_lock
-taking there.
-
-For dump handlers with RTNL_FLAG_DUMP_SPLIT_NLM_DONE we can
-avoid taking rtnl_lock just to generate NLM_DONE, once again.
-
-Signed-off-by: Jakub Kicinski <kuba@kernel.org>
-Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
-Reviewed-by: Eric Dumazet <edumazet@google.com>
-Signed-off-by: David S. Miller <davem@davemloft.net>
-Signed-off-by: Sasha Levin <sashal@kernel.org>
----
- net/core/rtnetlink.c | 9 +++++++--
- net/netlink/af_netlink.c | 2 --
- 2 files changed, 7 insertions(+), 4 deletions(-)
-
-diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
-index 5e589f0a62bc5..cb8792800cee8 100644
---- a/net/core/rtnetlink.c
-+++ b/net/core/rtnetlink.c
-@@ -6486,6 +6486,7 @@ static int rtnl_mdb_del(struct sk_buff *skb, struct nlmsghdr *nlh,
-
- static int rtnl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
- {
-+ const bool needs_lock = !(cb->flags & RTNL_FLAG_DUMP_UNLOCKED);
- rtnl_dumpit_func dumpit = cb->data;
- int err;
-
-@@ -6495,7 +6496,11 @@ static int rtnl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
- if (!dumpit)
- return 0;
-
-+ if (needs_lock)
-+ rtnl_lock();
- err = dumpit(skb, cb);
-+ if (needs_lock)
-+ rtnl_unlock();
-
- /* Old dump handlers used to send NLM_DONE as in a separate recvmsg().
- * Some applications which parse netlink manually depend on this.
-@@ -6515,7 +6520,8 @@ static int rtnetlink_dump_start(struct sock *ssk, struct sk_buff *skb,
- const struct nlmsghdr *nlh,
- struct netlink_dump_control *control)
- {
-- if (control->flags & RTNL_FLAG_DUMP_SPLIT_NLM_DONE) {
-+ if (control->flags & RTNL_FLAG_DUMP_SPLIT_NLM_DONE ||
-+ !(control->flags & RTNL_FLAG_DUMP_UNLOCKED)) {
- WARN_ON(control->data);
- control->data = control->dump;
- control->dump = rtnl_dumpit;
-@@ -6703,7 +6709,6 @@ static int __net_init rtnetlink_net_init(struct net *net)
- struct netlink_kernel_cfg cfg = {
- .groups = RTNLGRP_MAX,
- .input = rtnetlink_rcv,
-- .cb_mutex = &rtnl_mutex,
- .flags = NL_CFG_F_NONROOT_RECV,
- .bind = rtnetlink_bind,
- };
-diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
-index fa9c090cf629e..8bbbe75e75dbe 100644
---- a/net/netlink/af_netlink.c
-+++ b/net/netlink/af_netlink.c
-@@ -2330,8 +2330,6 @@ static int netlink_dump(struct sock *sk, bool lock_taken)
-
- cb->extack = &extack;
-
-- if (cb->flags & RTNL_FLAG_DUMP_UNLOCKED)
-- extra_mutex = NULL;
- if (extra_mutex)
- mutex_lock(extra_mutex);
- nlk->dump_done_errno = cb->dump(skb, cb);
---
-2.43.0
-