From 636af13f213bf9b28a34254327934bc72a797754 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 7 Nov 2024 16:48:23 -0800 Subject: [PATCH] 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},