From 167487070d644a285ed863516c80b3c35ec929d6 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 27 Feb 2024 09:24:11 +0000 Subject: inet: use xa_array iterator to implement inet_netconf_dump_devconf() 1) inet_netconf_dump_devconf() can run under RCU protection instead of RTNL. 2) properly return 0 at the end of a dump, avoiding an an extra recvmsg() system call. 3) Do not use inet_base_seq() anymore, for_each_netdev_dump() has nice properties. Restarting a GETDEVCONF dump if a device has been added/removed or if net->ipv4.dev_addr_genid has changed is moot. Signed-off-by: Eric Dumazet Reviewed-by: Jiri Pirko Link: https://lore.kernel.org/r/20240227092411.2315725-4-edumazet@google.com Signed-off-by: Jakub Kicinski --- net/ipv4/devinet.c | 101 +++++++++++++++++++++++------------------------------ 1 file changed, 43 insertions(+), 58 deletions(-) (limited to 'net/ipv4/devinet.c') diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c index f045a34e90b9..af741af61830 100644 --- a/net/ipv4/devinet.c +++ b/net/ipv4/devinet.c @@ -2267,11 +2267,13 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb, { const struct nlmsghdr *nlh = cb->nlh; struct net *net = sock_net(skb->sk); - int h, s_h; - int idx, s_idx; + struct { + unsigned long ifindex; + unsigned int all_default; + } *ctx = (void *)cb->ctx; + const struct in_device *in_dev; struct net_device *dev; - struct in_device *in_dev; - struct hlist_head *head; + int err = 0; if (cb->strict_check) { struct netlink_ext_ack *extack = cb->extack; @@ -2288,64 +2290,47 @@ static int inet_netconf_dump_devconf(struct sk_buff *skb, } } - s_h = cb->args[0]; - s_idx = idx = cb->args[1]; - - for (h = s_h; h < NETDEV_HASHENTRIES; h++, s_idx = 0) { - idx = 0; - head = &net->dev_index_head[h]; - rcu_read_lock(); - cb->seq = inet_base_seq(net); - hlist_for_each_entry_rcu(dev, head, index_hlist) { - if (idx < s_idx) - goto cont; - in_dev = __in_dev_get_rcu(dev); - if (!in_dev) - goto cont; - - if (inet_netconf_fill_devconf(skb, dev->ifindex, - &in_dev->cnf, - NETLINK_CB(cb->skb).portid, - nlh->nlmsg_seq, - RTM_NEWNETCONF, - NLM_F_MULTI, - NETCONFA_ALL) < 0) { - rcu_read_unlock(); - goto done; - } - nl_dump_check_consistent(cb, nlmsg_hdr(skb)); -cont: - idx++; - } - rcu_read_unlock(); + rcu_read_lock(); + for_each_netdev_dump(net, dev, ctx->ifindex) { + in_dev = __in_dev_get_rcu(dev); + if (!in_dev) + continue; + err = inet_netconf_fill_devconf(skb, dev->ifindex, + &in_dev->cnf, + NETLINK_CB(cb->skb).portid, + nlh->nlmsg_seq, + RTM_NEWNETCONF, NLM_F_MULTI, + NETCONFA_ALL); + if (err < 0) + goto done; } - if (h == NETDEV_HASHENTRIES) { - if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL, - net->ipv4.devconf_all, - NETLINK_CB(cb->skb).portid, - nlh->nlmsg_seq, - RTM_NEWNETCONF, NLM_F_MULTI, - NETCONFA_ALL) < 0) + if (ctx->all_default == 0) { + err = inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_ALL, + net->ipv4.devconf_all, + NETLINK_CB(cb->skb).portid, + nlh->nlmsg_seq, + RTM_NEWNETCONF, NLM_F_MULTI, + NETCONFA_ALL); + if (err < 0) goto done; - else - h++; - } - if (h == NETDEV_HASHENTRIES + 1) { - if (inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT, - net->ipv4.devconf_dflt, - NETLINK_CB(cb->skb).portid, - nlh->nlmsg_seq, - RTM_NEWNETCONF, NLM_F_MULTI, - NETCONFA_ALL) < 0) + ctx->all_default++; + } + if (ctx->all_default == 1) { + err = inet_netconf_fill_devconf(skb, NETCONFA_IFINDEX_DEFAULT, + net->ipv4.devconf_dflt, + NETLINK_CB(cb->skb).portid, + nlh->nlmsg_seq, + RTM_NEWNETCONF, NLM_F_MULTI, + NETCONFA_ALL); + if (err < 0) goto done; - else - h++; + ctx->all_default++; } done: - cb->args[0] = h; - cb->args[1] = idx; - - return skb->len; + if (err < 0 && likely(skb->len)) + err = skb->len; + rcu_read_unlock(); + return err; } #ifdef CONFIG_SYSCTL @@ -2829,5 +2814,5 @@ void __init devinet_init(void) rtnl_register(PF_INET, RTM_GETADDR, NULL, inet_dump_ifaddr, 0); rtnl_register(PF_INET, RTM_GETNETCONF, inet_netconf_get_devconf, inet_netconf_dump_devconf, - RTNL_FLAG_DOIT_UNLOCKED); + RTNL_FLAG_DOIT_UNLOCKED | RTNL_FLAG_DUMP_UNLOCKED); } -- cgit v1.2.3