From d5ec8d91f82ef78405b506737952dec8af95a95b Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:14 -0800 Subject: rtnetlink: Remove __rtnl_link_unregister(). rtnl_link_unregister() holds RTNL and calls __rtnl_link_unregister(), where we call synchronize_srcu() to wait inflight RTM_NEWLINK requests for per-netns RTNL. We put synchronize_srcu() in __rtnl_link_unregister() due to ifb.ko and dummy.ko. However, rtnl_newlink() will acquire SRCU before RTNL later in this series. Then, lockdep will detect the deadlock: rtnl_link_unregister() rtnl_newlink() ---- ---- lock(rtnl_mutex); lock(&ops->srcu); lock(rtnl_mutex); sync(&ops->srcu); To avoid the problem, we must call synchronize_srcu() before RTNL in rtnl_link_unregister(). As a preparation, let's remove __rtnl_link_unregister(). Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241108004823.29419-2-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- drivers/net/dummy.c | 6 +++++- drivers/net/ifb.c | 6 +++++- include/net/rtnetlink.h | 1 - net/core/rtnetlink.c | 32 ++++++++++---------------------- 4 files changed, 20 insertions(+), 25 deletions(-) diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c index e9c5e1e11fa0..72618b6af44e 100644 --- a/drivers/net/dummy.c +++ b/drivers/net/dummy.c @@ -166,6 +166,7 @@ err: static int __init dummy_init_module(void) { + bool need_unregister = false; int i, err = 0; down_write(&pernet_ops_rwsem); @@ -179,12 +180,15 @@ static int __init dummy_init_module(void) cond_resched(); } if (err < 0) - __rtnl_link_unregister(&dummy_link_ops); + need_unregister = true; out: rtnl_unlock(); up_write(&pernet_ops_rwsem); + if (need_unregister) + rtnl_link_unregister(&dummy_link_ops); + return err; } diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c index 2c1b5def4a0b..a4b9ec4e8f30 100644 --- a/drivers/net/ifb.c +++ b/drivers/net/ifb.c @@ -424,6 +424,7 @@ err: static int __init ifb_init_module(void) { + bool need_unregister = false; int i, err; down_write(&pernet_ops_rwsem); @@ -437,12 +438,15 @@ static int __init ifb_init_module(void) cond_resched(); } if (err) - __rtnl_link_unregister(&ifb_link_ops); + need_unregister = true; out: rtnl_unlock(); up_write(&pernet_ops_rwsem); + if (need_unregister) + rtnl_link_unregister(&ifb_link_ops); + return err; } diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index b260c0cc9671..3ebfcc6e56fd 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -165,7 +165,6 @@ struct rtnl_link_ops { }; int __rtnl_link_register(struct rtnl_link_ops *ops); -void __rtnl_link_unregister(struct rtnl_link_ops *ops); int rtnl_link_register(struct rtnl_link_ops *ops); void rtnl_link_unregister(struct rtnl_link_ops *ops); diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index a5c386a45501..f0246ecec7fa 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -568,27 +568,6 @@ static void __rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops) unregister_netdevice_many(&list_kill); } -/** - * __rtnl_link_unregister - Unregister rtnl_link_ops from rtnetlink. - * @ops: struct rtnl_link_ops * to unregister - * - * The caller must hold the rtnl_mutex and guarantee net_namespace_list - * integrity (hold pernet_ops_rwsem for writing to close the race - * with setup_net() and cleanup_net()). - */ -void __rtnl_link_unregister(struct rtnl_link_ops *ops) -{ - struct net *net; - - list_del_rcu(&ops->list); - synchronize_srcu(&ops->srcu); - cleanup_srcu_struct(&ops->srcu); - - for_each_net(net) - __rtnl_kill_links(net, ops); -} -EXPORT_SYMBOL_GPL(__rtnl_link_unregister); - /* Return with the rtnl_lock held when there are no network * devices unregistering in any network namespace. */ @@ -617,10 +596,19 @@ static void rtnl_lock_unregistering_all(void) */ void rtnl_link_unregister(struct rtnl_link_ops *ops) { + struct net *net; + /* Close the race with setup_net() and cleanup_net() */ down_write(&pernet_ops_rwsem); rtnl_lock_unregistering_all(); - __rtnl_link_unregister(ops); + + list_del_rcu(&ops->list); + synchronize_srcu(&ops->srcu); + cleanup_srcu_struct(&ops->srcu); + + for_each_net(net) + __rtnl_kill_links(net, ops); + rtnl_unlock(); up_write(&pernet_ops_rwsem); } -- cgit v1.2.3 From 6b57ff21a3109b1dba2d286ff415463e6fb1fca3 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:15 -0800 Subject: rtnetlink: Protect link_ops by mutex. rtnl_link_unregister() holds RTNL and calls synchronize_srcu(), but rtnl_newlink() will acquire SRCU frist and then RTNL. Then, we need to unlink ops and call synchronize_srcu() outside of RTNL to avoid the deadlock. rtnl_link_unregister() rtnl_newlink() ---- ---- lock(rtnl_mutex); lock(&ops->srcu); lock(rtnl_mutex); sync(&ops->srcu); Let's move as such and add a mutex to protect link_ops. Now, link_ops is protected by its dedicated mutex and rtnl_link_register() no longer needs to hold RTNL. While at it, we move the initialisation of ops->dellink and ops->srcu out of the mutex scope. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241108004823.29419-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- include/net/rtnetlink.h | 2 +- net/core/rtnetlink.c | 33 ++++++++++++++++++++------------- 2 files changed, 21 insertions(+), 14 deletions(-) diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index 3ebfcc6e56fd..7559020f760c 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -71,7 +71,7 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh) /** * struct rtnl_link_ops - rtnetlink link operations * - * @list: Used internally, protected by RTNL and SRCU + * @list: Used internally, protected by link_ops_mutex and SRCU * @srcu: Used internally * @kind: Identifier * @netns_refund: Physical device, move to init_net on netns exit diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index f0246ecec7fa..21154ef0048f 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -466,6 +466,7 @@ void __rtnl_unregister_many(const struct rtnl_msg_handler *handlers, int n) } EXPORT_SYMBOL_GPL(__rtnl_unregister_many); +static DEFINE_MUTEX(link_ops_mutex); static LIST_HEAD(link_ops); static struct rtnl_link_ops *rtnl_link_ops_get(const char *kind, int *srcu_index) @@ -508,14 +509,6 @@ int __rtnl_link_register(struct rtnl_link_ops *ops) struct rtnl_link_ops *tmp; int err; - /* When RTNL is removed, add lock for link_ops. */ - ASSERT_RTNL(); - - list_for_each_entry(tmp, &link_ops, list) { - if (!strcmp(ops->kind, tmp->kind)) - return -EEXIST; - } - /* The check for alloc/setup is here because if ops * does not have that filled up, it is not possible * to use the ops for creating device. So do not @@ -528,9 +521,20 @@ int __rtnl_link_register(struct rtnl_link_ops *ops) if (err) return err; + mutex_lock(&link_ops_mutex); + + list_for_each_entry(tmp, &link_ops, list) { + if (!strcmp(ops->kind, tmp->kind)) { + err = -EEXIST; + goto unlock; + } + } + list_add_tail_rcu(&ops->list, &link_ops); +unlock: + mutex_unlock(&link_ops_mutex); - return 0; + return err; } EXPORT_SYMBOL_GPL(__rtnl_link_register); @@ -598,14 +602,17 @@ void rtnl_link_unregister(struct rtnl_link_ops *ops) { struct net *net; - /* Close the race with setup_net() and cleanup_net() */ - down_write(&pernet_ops_rwsem); - rtnl_lock_unregistering_all(); - + mutex_lock(&link_ops_mutex); list_del_rcu(&ops->list); + mutex_unlock(&link_ops_mutex); + synchronize_srcu(&ops->srcu); cleanup_srcu_struct(&ops->srcu); + /* Close the race with setup_net() and cleanup_net() */ + down_write(&pernet_ops_rwsem); + rtnl_lock_unregistering_all(); + for_each_net(net) __rtnl_kill_links(net, ops); -- cgit v1.2.3 From 68297dbb967f87c3c92af9d2f652270f57c547c7 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:16 -0800 Subject: rtnetlink: Remove __rtnl_link_register() link_ops is protected by link_ops_mutex and no longer needs RTNL, so we have no reason to have __rtnl_link_register() separately. Let's remove it and call rtnl_link_register() from ifb.ko and dummy.ko. Note that both modules' init() work on init_net only, so we need not export pernet_ops_rwsem and can use rtnl_net_lock() there. Signed-off-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20241108004823.29419-4-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- drivers/net/dummy.c | 17 ++++++----------- drivers/net/ifb.c | 17 ++++++----------- include/net/rtnetlink.h | 2 -- net/core/net_namespace.c | 1 - net/core/rtnetlink.c | 35 +++++++---------------------------- 5 files changed, 19 insertions(+), 53 deletions(-) diff --git a/drivers/net/dummy.c b/drivers/net/dummy.c index 72618b6af44e..005d79975f3b 100644 --- a/drivers/net/dummy.c +++ b/drivers/net/dummy.c @@ -166,27 +166,22 @@ err: static int __init dummy_init_module(void) { - bool need_unregister = false; int i, err = 0; - down_write(&pernet_ops_rwsem); - rtnl_lock(); - err = __rtnl_link_register(&dummy_link_ops); + err = rtnl_link_register(&dummy_link_ops); if (err < 0) - goto out; + return err; + + rtnl_net_lock(&init_net); for (i = 0; i < numdummies && !err; i++) { err = dummy_init_one(); cond_resched(); } - if (err < 0) - need_unregister = true; -out: - rtnl_unlock(); - up_write(&pernet_ops_rwsem); + rtnl_net_unlock(&init_net); - if (need_unregister) + if (err < 0) rtnl_link_unregister(&dummy_link_ops); return err; diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c index a4b9ec4e8f30..67424888ff0a 100644 --- a/drivers/net/ifb.c +++ b/drivers/net/ifb.c @@ -424,27 +424,22 @@ err: static int __init ifb_init_module(void) { - bool need_unregister = false; int i, err; - down_write(&pernet_ops_rwsem); - rtnl_lock(); - err = __rtnl_link_register(&ifb_link_ops); + err = rtnl_link_register(&ifb_link_ops); if (err < 0) - goto out; + return err; + + rtnl_net_lock(&init_net); for (i = 0; i < numifbs && !err; i++) { err = ifb_init_one(i); cond_resched(); } - if (err) - need_unregister = true; -out: - rtnl_unlock(); - up_write(&pernet_ops_rwsem); + rtnl_net_unlock(&init_net); - if (need_unregister) + if (err) rtnl_link_unregister(&ifb_link_ops); return err; diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index 7559020f760c..ef7c11f0d74c 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -164,8 +164,6 @@ struct rtnl_link_ops { int *prividx, int attr); }; -int __rtnl_link_register(struct rtnl_link_ops *ops); - int rtnl_link_register(struct rtnl_link_ops *ops); void rtnl_link_unregister(struct rtnl_link_ops *ops); diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 809b48c0a528..157021ced442 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -56,7 +56,6 @@ static bool init_net_initialized; * outside. */ DECLARE_RWSEM(pernet_ops_rwsem); -EXPORT_SYMBOL_GPL(pernet_ops_rwsem); #define MIN_PERNET_OPS_ID \ ((sizeof(struct net_generic) + sizeof(void *) - 1) / sizeof(void *)) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 21154ef0048f..e8357a3b9c7e 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -495,20 +495,21 @@ static void rtnl_link_ops_put(struct rtnl_link_ops *ops, int srcu_index) } /** - * __rtnl_link_register - Register rtnl_link_ops with rtnetlink. + * rtnl_link_register - Register rtnl_link_ops with rtnetlink. * @ops: struct rtnl_link_ops * to register * - * The caller must hold the rtnl_mutex. This function should be used - * by drivers that create devices during module initialization. It - * must be called before registering the devices. - * * Returns 0 on success or a negative error code. */ -int __rtnl_link_register(struct rtnl_link_ops *ops) +int rtnl_link_register(struct rtnl_link_ops *ops) { struct rtnl_link_ops *tmp; int err; + /* Sanity-check max sizes to avoid stack buffer overflow. */ + if (WARN_ON(ops->maxtype > RTNL_MAX_TYPE || + ops->slave_maxtype > RTNL_SLAVE_MAX_TYPE)) + return -EINVAL; + /* The check for alloc/setup is here because if ops * does not have that filled up, it is not possible * to use the ops for creating device. So do not @@ -536,28 +537,6 @@ unlock: return err; } -EXPORT_SYMBOL_GPL(__rtnl_link_register); - -/** - * rtnl_link_register - Register rtnl_link_ops with rtnetlink. - * @ops: struct rtnl_link_ops * to register - * - * Returns 0 on success or a negative error code. - */ -int rtnl_link_register(struct rtnl_link_ops *ops) -{ - int err; - - /* Sanity-check max sizes to avoid stack buffer overflow. */ - if (WARN_ON(ops->maxtype > RTNL_MAX_TYPE || - ops->slave_maxtype > RTNL_SLAVE_MAX_TYPE)) - return -EINVAL; - - rtnl_lock(); - err = __rtnl_link_register(ops); - rtnl_unlock(); - return err; -} EXPORT_SYMBOL_GPL(rtnl_link_register); static void __rtnl_kill_links(struct net *net, struct rtnl_link_ops *ops) -- cgit v1.2.3 From cbaaa6326bc58e75239df437a8fdcdb2335d3b24 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:17 -0800 Subject: rtnetlink: Introduce struct rtnl_nets and helpers. rtnl_newlink() needs to hold 3 per-netns RTNL: 2 for a new device and 1 for its peer. We will add rtnl_nets_lock() later, which performs the nested locking based on struct rtnl_nets, which has an array of struct net pointers. rtnl_nets_add() adds a net pointer to the array and sorts it so that rtnl_nets_lock() can simply acquire per-netns RTNL from array[0] to [2]. Before calling rtnl_nets_add(), get_net() must be called for the net, and rtnl_nets_destroy() will call put_net() for each. Let's apply the helpers to rtnl_newlink(). When CONFIG_DEBUG_NET_SMALL_RTNL is disabled, we do not call rtnl_net_lock() thus do not care about the array order, so rtnl_net_cmp_locks() returns -1 so that the loop in rtnl_nets_add() can be optimised to NOP. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-5-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 67 insertions(+), 3 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index e8357a3b9c7e..960d9d2c6aec 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -258,8 +258,67 @@ bool lockdep_rtnl_net_is_held(struct net *net) return lockdep_rtnl_is_held() && lockdep_is_held(&net->rtnl_mutex); } EXPORT_SYMBOL(lockdep_rtnl_net_is_held); +#else +static int rtnl_net_cmp_locks(const struct net *net_a, const struct net *net_b) +{ + /* No need to swap */ + return -1; +} #endif +struct rtnl_nets { + /* ->newlink() needs to freeze 3 netns at most; + * 2 for the new device, 1 for its peer. + */ + struct net *net[3]; + unsigned char len; +}; + +static void rtnl_nets_init(struct rtnl_nets *rtnl_nets) +{ + memset(rtnl_nets, 0, sizeof(*rtnl_nets)); +} + +static void rtnl_nets_destroy(struct rtnl_nets *rtnl_nets) +{ + int i; + + for (i = 0; i < rtnl_nets->len; i++) { + put_net(rtnl_nets->net[i]); + rtnl_nets->net[i] = NULL; + } + + rtnl_nets->len = 0; +} + +/** + * rtnl_nets_add - Add netns to be locked before ->newlink(). + * + * @rtnl_nets: rtnl_nets pointer passed to ->get_peer_net(). + * @net: netns pointer with an extra refcnt held. + * + * The extra refcnt is released in rtnl_nets_destroy(). + */ +static void rtnl_nets_add(struct rtnl_nets *rtnl_nets, struct net *net) +{ + int i; + + DEBUG_NET_WARN_ON_ONCE(rtnl_nets->len == ARRAY_SIZE(rtnl_nets->net)); + + for (i = 0; i < rtnl_nets->len; i++) { + switch (rtnl_net_cmp_locks(rtnl_nets->net[i], net)) { + case 0: + put_net(net); + return; + case 1: + swap(rtnl_nets->net[i], net); + } + } + + rtnl_nets->net[i] = net; + rtnl_nets->len++; +} + static struct rtnl_link __rcu *__rcu *rtnl_msg_handlers[RTNL_FAMILY_MAX + 1]; static inline int rtm_msgindex(int msgtype) @@ -3767,6 +3826,7 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, struct net *tgt_net, *link_net = NULL; struct rtnl_link_ops *ops = NULL; struct rtnl_newlink_tbs *tbs; + struct rtnl_nets rtnl_nets; int ops_srcu_index; int ret; @@ -3810,6 +3870,8 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, #endif } + rtnl_nets_init(&rtnl_nets); + if (ops) { if (ops->maxtype > RTNL_MAX_TYPE) { ret = -EINVAL; @@ -3839,6 +3901,8 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, goto put_ops; } + rtnl_nets_add(&rtnl_nets, tgt_net); + if (tb[IFLA_LINK_NETNSID]) { int id = nla_get_s32(tb[IFLA_LINK_NETNSID]); @@ -3849,6 +3913,8 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, goto put_net; } + rtnl_nets_add(&rtnl_nets, link_net); + if (!netlink_ns_capable(skb, link_net->user_ns, CAP_NET_ADMIN)) { ret = -EPERM; goto put_net; @@ -3858,9 +3924,7 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, ret = __rtnl_newlink(skb, nlh, ops, tgt_net, link_net, tbs, data, extack); put_net: - if (link_net) - put_net(link_net); - put_net(tgt_net); + rtnl_nets_destroy(&rtnl_nets); put_ops: if (ops) rtnl_link_ops_put(ops, ops_srcu_index); -- cgit v1.2.3 From 28690e5361c05fd4ef0ca3a17d1c667cba790554 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:18 -0800 Subject: rtnetlink: Add peer_type in struct rtnl_link_ops. In ops->newlink(), veth, vxcan, and netkit call rtnl_link_get_net() with a net pointer, which is the first argument of ->newlink(). rtnl_link_get_net() could return another netns based on IFLA_NET_NS_PID and IFLA_NET_NS_FD in the peer device's attributes. We want to get it and fill rtnl_nets->nets[] in advance in rtnl_newlink() for per-netns RTNL. All of the three get the peer netns in the same way: 1. Call rtnl_nla_parse_ifinfomsg() 2. Call ops->validate() (vxcan doesn't have) 3. Call rtnl_link_get_net_tb() Let's add a new field peer_type to struct rtnl_link_ops and prefetch netns in the peer ifla to add it to rtnl_nets in rtnl_newlink(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-6-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- include/net/rtnetlink.h | 2 ++ net/core/rtnetlink.c | 55 +++++++++++++++++++++++++++++++++++++++++++++---- 2 files changed, 53 insertions(+), 4 deletions(-) diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index ef7c11f0d74c..bef76abcff8d 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -75,6 +75,7 @@ static inline int rtnl_msg_family(const struct nlmsghdr *nlh) * @srcu: Used internally * @kind: Identifier * @netns_refund: Physical device, move to init_net on netns exit + * @peer_type: Peer device specific netlink attribute number (e.g. VETH_INFO_PEER) * @maxtype: Highest device specific netlink attribute number * @policy: Netlink policy for device specific attribute validation * @validate: Optional validation function for netlink/changelink parameters @@ -116,6 +117,7 @@ struct rtnl_link_ops { void (*setup)(struct net_device *dev); bool netns_refund; + const u16 peer_type; unsigned int maxtype; const struct nla_policy *policy; int (*validate)(struct nlattr *tb[], diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 960d9d2c6aec..1af187a4a3f1 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -2492,9 +2492,10 @@ int rtnl_nla_parse_ifinfomsg(struct nlattr **tb, const struct nlattr *nla_peer, } EXPORT_SYMBOL(rtnl_nla_parse_ifinfomsg); -struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]) +static struct net *rtnl_link_get_net_ifla(struct nlattr *tb[]) { - struct net *net; + struct net *net = NULL; + /* Examine the link attributes and figure out which * network namespace we are talking about. */ @@ -2502,8 +2503,17 @@ struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]) net = get_net_ns_by_pid(nla_get_u32(tb[IFLA_NET_NS_PID])); else if (tb[IFLA_NET_NS_FD]) net = get_net_ns_by_fd(nla_get_u32(tb[IFLA_NET_NS_FD])); - else + + return net; +} + +struct net *rtnl_link_get_net(struct net *src_net, struct nlattr *tb[]) +{ + struct net *net = rtnl_link_get_net_ifla(tb); + + if (!net) net = get_net(src_net); + return net; } EXPORT_SYMBOL(rtnl_link_get_net); @@ -3765,6 +3775,37 @@ out_unregister: goto out; } +static int rtnl_add_peer_net(struct rtnl_nets *rtnl_nets, + const struct rtnl_link_ops *ops, + struct nlattr *data[], + struct netlink_ext_ack *extack) +{ + struct nlattr *tb[IFLA_MAX + 1]; + struct net *net; + int err; + + if (!data || !data[ops->peer_type]) + return 0; + + err = rtnl_nla_parse_ifinfomsg(tb, data[ops->peer_type], extack); + if (err < 0) + return err; + + if (ops->validate) { + err = ops->validate(tb, NULL, extack); + if (err < 0) + return err; + } + + net = rtnl_link_get_net_ifla(tb); + if (IS_ERR(net)) + return PTR_ERR(net); + if (net) + rtnl_nets_add(rtnl_nets, net); + + return 0; +} + static int __rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, const struct rtnl_link_ops *ops, struct net *tgt_net, struct net *link_net, @@ -3893,12 +3934,18 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, if (ret < 0) goto put_ops; } + + if (ops->peer_type) { + ret = rtnl_add_peer_net(&rtnl_nets, ops, data, extack); + if (ret < 0) + goto put_ops; + } } tgt_net = rtnl_link_get_net_capable(skb, sock_net(skb->sk), tb, CAP_NET_ADMIN); if (IS_ERR(tgt_net)) { ret = PTR_ERR(tgt_net); - goto put_ops; + goto put_net; } rtnl_nets_add(&rtnl_nets, tgt_net); -- cgit v1.2.3 From 0eb87b02a7058f1dc64bcd6fa619d8556186de3d Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:19 -0800 Subject: veth: Set VETH_INFO_PEER to veth_link_ops.peer_type. For per-netns RTNL, we need to prefetch the peer device's netns. Let's set rtnl_link_ops.peer_type and accordingly remove duplicated validation in ->newlink(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-7-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- drivers/net/veth.c | 18 ++++-------------- 1 file changed, 4 insertions(+), 14 deletions(-) diff --git a/drivers/net/veth.c b/drivers/net/veth.c index 18148e068aa0..0d6d0d749d44 100644 --- a/drivers/net/veth.c +++ b/drivers/net/veth.c @@ -1781,19 +1781,11 @@ static int veth_newlink(struct net *src_net, struct net_device *dev, /* * create and register peer first */ - if (data != NULL && data[VETH_INFO_PEER] != NULL) { - struct nlattr *nla_peer; + if (data && data[VETH_INFO_PEER]) { + struct nlattr *nla_peer = data[VETH_INFO_PEER]; - nla_peer = data[VETH_INFO_PEER]; ifmp = nla_data(nla_peer); - err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack); - if (err < 0) - return err; - - err = veth_validate(peer_tb, NULL, extack); - if (err < 0) - return err; - + rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack); tbp = peer_tb; } else { ifmp = NULL; @@ -1809,9 +1801,6 @@ static int veth_newlink(struct net *src_net, struct net_device *dev, } net = rtnl_link_get_net(src_net, tbp); - if (IS_ERR(net)) - return PTR_ERR(net); - peer = rtnl_create_link(net, ifname, name_assign_type, &veth_link_ops, tbp, extack); if (IS_ERR(peer)) { @@ -1952,6 +1941,7 @@ static struct rtnl_link_ops veth_link_ops = { .newlink = veth_newlink, .dellink = veth_dellink, .policy = veth_policy, + .peer_type = VETH_INFO_PEER, .maxtype = VETH_INFO_MAX, .get_link_net = veth_get_link_net, .get_num_tx_queues = veth_get_num_queues, -- cgit v1.2.3 From 6b84e558e95d95f3bb1139dfbb693bc22c760dad Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:20 -0800 Subject: vxcan: Set VXCAN_INFO_PEER to vxcan_link_ops.peer_type. For per-netns RTNL, we need to prefetch the peer device's netns. Let's set rtnl_link_ops.peer_type and accordingly remove duplicated validation in ->newlink(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-8-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- drivers/net/can/vxcan.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/drivers/net/can/vxcan.c b/drivers/net/can/vxcan.c index 9e1b7d41005f..da7c72105fb6 100644 --- a/drivers/net/can/vxcan.c +++ b/drivers/net/can/vxcan.c @@ -188,14 +188,10 @@ static int vxcan_newlink(struct net *net, struct net_device *dev, /* register peer device */ if (data && data[VXCAN_INFO_PEER]) { - struct nlattr *nla_peer; + struct nlattr *nla_peer = data[VXCAN_INFO_PEER]; - nla_peer = data[VXCAN_INFO_PEER]; ifmp = nla_data(nla_peer); - err = rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack); - if (err < 0) - return err; - + rtnl_nla_parse_ifinfomsg(peer_tb, nla_peer, extack); tbp = peer_tb; } @@ -208,9 +204,6 @@ static int vxcan_newlink(struct net *net, struct net_device *dev, } peer_net = rtnl_link_get_net(net, tbp); - if (IS_ERR(peer_net)) - return PTR_ERR(peer_net); - peer = rtnl_create_link(peer_net, ifname, name_assign_type, &vxcan_link_ops, tbp, extack); if (IS_ERR(peer)) { @@ -302,6 +295,7 @@ static struct rtnl_link_ops vxcan_link_ops = { .newlink = vxcan_newlink, .dellink = vxcan_dellink, .policy = vxcan_policy, + .peer_type = VXCAN_INFO_PEER, .maxtype = VXCAN_INFO_MAX, .get_link_net = vxcan_get_link_net, }; -- cgit v1.2.3 From fefd5d08217284a8894502eb1148ff88bc8510c0 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:21 -0800 Subject: netkit: Set IFLA_NETKIT_PEER_INFO to netkit_link_ops.peer_type. For per-netns RTNL, we need to prefetch the peer device's netns. Let's set rtnl_link_ops.peer_type and accordingly remove duplicated validation in ->newlink(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Acked-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-9-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- drivers/net/netkit.c | 11 ++--------- 1 file changed, 2 insertions(+), 9 deletions(-) diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c index cd8360b9bbde..bb07725d1c72 100644 --- a/drivers/net/netkit.c +++ b/drivers/net/netkit.c @@ -351,12 +351,7 @@ static int netkit_new_link(struct net *src_net, struct net_device *dev, if (data[IFLA_NETKIT_PEER_INFO]) { attr = data[IFLA_NETKIT_PEER_INFO]; ifmp = nla_data(attr); - err = rtnl_nla_parse_ifinfomsg(peer_tb, attr, extack); - if (err < 0) - return err; - err = netkit_validate(peer_tb, NULL, extack); - if (err < 0) - return err; + rtnl_nla_parse_ifinfomsg(peer_tb, attr, extack); tbp = peer_tb; } if (data[IFLA_NETKIT_SCRUB]) @@ -391,9 +386,6 @@ static int netkit_new_link(struct net *src_net, struct net_device *dev, return -EOPNOTSUPP; net = rtnl_link_get_net(src_net, tbp); - if (IS_ERR(net)) - return PTR_ERR(net); - peer = rtnl_create_link(net, ifname, ifname_assign_type, &netkit_link_ops, tbp, extack); if (IS_ERR(peer)) { @@ -978,6 +970,7 @@ static struct rtnl_link_ops netkit_link_ops = { .fill_info = netkit_fill_info, .policy = netkit_policy, .validate = netkit_validate, + .peer_type = IFLA_NETKIT_PEER_INFO, .maxtype = IFLA_NETKIT_MAX, }; -- cgit v1.2.3 From d91191ffe23f927b14b8e861f22037cf153c48cb Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:22 -0800 Subject: rtnetlink: Convert RTM_NEWLINK to per-netns RTNL. Now, we are ready to convert rtnl_newlink() to per-netns RTNL; rtnl_link_ops is protected by SRCU and netns is prefetched in rtnl_newlink(). Let's register rtnl_newlink() with RTNL_FLAG_DOIT_PERNET and push RTNL down as rtnl_nets_lock(). Signed-off-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/20241108004823.29419-10-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- net/core/rtnetlink.c | 27 ++++++++++++++++++++++++--- 1 file changed, 24 insertions(+), 3 deletions(-) diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 1af187a4a3f1..30191d17add3 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -319,6 +319,26 @@ static void rtnl_nets_add(struct rtnl_nets *rtnl_nets, struct net *net) rtnl_nets->len++; } +static void rtnl_nets_lock(struct rtnl_nets *rtnl_nets) +{ + int i; + + rtnl_lock(); + + for (i = 0; i < rtnl_nets->len; i++) + __rtnl_net_lock(rtnl_nets->net[i]); +} + +static void rtnl_nets_unlock(struct rtnl_nets *rtnl_nets) +{ + int i; + + for (i = 0; i < rtnl_nets->len; i++) + __rtnl_net_unlock(rtnl_nets->net[i]); + + rtnl_unlock(); +} + static struct rtnl_link __rcu *__rcu *rtnl_msg_handlers[RTNL_FAMILY_MAX + 1]; static inline int rtm_msgindex(int msgtype) @@ -3903,9 +3923,7 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, ops = rtnl_link_ops_get(kind, &ops_srcu_index); #ifdef CONFIG_MODULES if (!ops) { - __rtnl_unlock(); request_module("rtnl-link-%s", kind); - rtnl_lock(); ops = rtnl_link_ops_get(kind, &ops_srcu_index); } #endif @@ -3968,7 +3986,9 @@ static int rtnl_newlink(struct sk_buff *skb, struct nlmsghdr *nlh, } } + rtnl_nets_lock(&rtnl_nets); ret = __rtnl_newlink(skb, nlh, ops, tgt_net, link_net, tbs, data, extack); + rtnl_nets_unlock(&rtnl_nets); put_net: rtnl_nets_destroy(&rtnl_nets); @@ -6972,7 +6992,8 @@ static struct pernet_operations rtnetlink_net_ops = { }; static const struct rtnl_msg_handler rtnetlink_rtnl_msg_handlers[] __initconst = { - {.msgtype = RTM_NEWLINK, .doit = rtnl_newlink}, + {.msgtype = RTM_NEWLINK, .doit = rtnl_newlink, + .flags = RTNL_FLAG_DOIT_PERNET}, {.msgtype = RTM_DELLINK, .doit = rtnl_dellink}, {.msgtype = RTM_GETLINK, .doit = rtnl_getlink, .dumpit = rtnl_dump_ifinfo, .flags = RTNL_FLAG_DUMP_SPLIT_NLM_DONE}, -- cgit v1.2.3 From 636af13f213bf9b28a34254327934bc72a797754 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:23 -0800 Subject: rtnetlink: Register rtnl_dellink() and rtnl_setlink() with RTNL_FLAG_DOIT_PERNET_WIP. Currently, rtnl_setlink() and rtnl_dellink() cannot be fully converted to per-netns RTNL due to a lack of handling peer/lower/upper devices in different netns. For example, when we change a device in rtnl_setlink() and need to propagate that to its upper devices, we want to avoid acquiring all netns locks, for which we do not know the upper limit. The same situation happens when we remove a device. rtnl_dellink() could be transformed to remove a single device in the requested netns and delegate other devices to per-netns work, and rtnl_setlink() might be ? Until we come up with a better idea, let's use a new flag RTNL_FLAG_DOIT_PERNET_WIP for rtnl_dellink() and rtnl_setlink(). This will unblock converting RTNL users where such devices are not related. Signed-off-by: Kuniyuki Iwashima Reviewed-by: Nikolay Aleksandrov Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20241108004823.29419-11-kuniyu@amazon.com Signed-off-by: Jakub Kicinski --- include/net/rtnetlink.h | 1 + net/core/rtnetlink.c | 19 ++++++++++++++++--- 2 files changed, 17 insertions(+), 3 deletions(-) diff --git a/include/net/rtnetlink.h b/include/net/rtnetlink.h index bef76abcff8d..bc0069a8b6ea 100644 --- a/include/net/rtnetlink.h +++ b/include/net/rtnetlink.h @@ -13,6 +13,7 @@ typedef int (*rtnl_dumpit_func)(struct sk_buff *, struct netlink_callback *); enum rtnl_link_flags { RTNL_FLAG_DOIT_UNLOCKED = BIT(0), #define RTNL_FLAG_DOIT_PERNET RTNL_FLAG_DOIT_UNLOCKED +#define RTNL_FLAG_DOIT_PERNET_WIP RTNL_FLAG_DOIT_UNLOCKED RTNL_FLAG_BULK_DEL_SUPPORTED = BIT(1), RTNL_FLAG_DUMP_UNLOCKED = BIT(2), RTNL_FLAG_DUMP_SPLIT_NLM_DONE = BIT(3), /* legacy behavior */ diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c index 30191d17add3..327fa4957929 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -3379,6 +3379,7 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, struct net *net = sock_net(skb->sk); struct nlattr *tb[IFLA_MAX+1]; struct net_device *dev = NULL; + struct rtnl_nets rtnl_nets; struct net *tgt_net; int err; @@ -3397,6 +3398,12 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, goto errout; } + rtnl_nets_init(&rtnl_nets); + rtnl_nets_add(&rtnl_nets, get_net(net)); + rtnl_nets_add(&rtnl_nets, tgt_net); + + rtnl_nets_lock(&rtnl_nets); + if (ifm->ifi_index > 0) dev = __dev_get_by_index(net, ifm->ifi_index); else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) @@ -3409,7 +3416,7 @@ static int rtnl_setlink(struct sk_buff *skb, struct nlmsghdr *nlh, else if (!err) err = -ENODEV; - put_net(tgt_net); + rtnl_nets_unlock(&rtnl_nets); errout: return err; } @@ -3494,6 +3501,8 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, return PTR_ERR(tgt_net); } + rtnl_net_lock(tgt_net); + if (ifm->ifi_index > 0) dev = __dev_get_by_index(tgt_net, ifm->ifi_index); else if (tb[IFLA_IFNAME] || tb[IFLA_ALT_IFNAME]) @@ -3508,6 +3517,8 @@ static int rtnl_dellink(struct sk_buff *skb, struct nlmsghdr *nlh, else err = -EINVAL; + rtnl_net_unlock(tgt_net); + if (netnsid >= 0) put_net(tgt_net); @@ -6994,10 +7005,12 @@ static struct pernet_operations rtnetlink_net_ops = { static const struct rtnl_msg_handler rtnetlink_rtnl_msg_handlers[] __initconst = { {.msgtype = RTM_NEWLINK, .doit = rtnl_newlink, .flags = RTNL_FLAG_DOIT_PERNET}, - {.msgtype = RTM_DELLINK, .doit = rtnl_dellink}, + {.msgtype = RTM_DELLINK, .doit = rtnl_dellink, + .flags = RTNL_FLAG_DOIT_PERNET_WIP}, {.msgtype = RTM_GETLINK, .doit = rtnl_getlink, .dumpit = rtnl_dump_ifinfo, .flags = RTNL_FLAG_DUMP_SPLIT_NLM_DONE}, - {.msgtype = RTM_SETLINK, .doit = rtnl_setlink}, + {.msgtype = RTM_SETLINK, .doit = rtnl_setlink, + .flags = RTNL_FLAG_DOIT_PERNET_WIP}, {.msgtype = RTM_GETADDR, .dumpit = rtnl_dump_all}, {.msgtype = RTM_GETROUTE, .dumpit = rtnl_dump_all}, {.msgtype = RTM_GETNETCONF, .dumpit = rtnl_dump_all}, -- cgit v1.2.3