From ad202074320cd75b31b8cdb58cca0d4ef6aaea8a Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Fri, 19 Aug 2016 16:21:37 +0800 Subject: [PATCH] netlink: Use rhashtable walk interface in diag dump This patch converts the diag dumping code to use the rhashtable walk code instead of going through rhashtable by hand. The lock nl_table_lock is now only taken while we process the multicast list as it's not needed for the rhashtable walk. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- net/netlink/diag.c | 103 ++++++++++++++++++++++++++++++++------------- 1 file changed, 73 insertions(+), 30 deletions(-) diff --git a/net/netlink/diag.c b/net/netlink/diag.c index 8dd836a8dd60..3e3e2534478a 100644 --- a/net/netlink/diag.c +++ b/net/netlink/diag.c @@ -63,43 +63,75 @@ out_nlmsg_trim: static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb, int protocol, int s_num) { + struct rhashtable_iter *hti = (void *)cb->args[2]; struct netlink_table *tbl = &nl_table[protocol]; - struct rhashtable *ht = &tbl->hash; - const struct bucket_table *htbl = rht_dereference_rcu(ht->tbl, ht); struct net *net = sock_net(skb->sk); struct netlink_diag_req *req; struct netlink_sock *nlsk; struct sock *sk; - int ret = 0, num = 0, i; + int num = 2; + int ret = 0; req = nlmsg_data(cb->nlh); - for (i = 0; i < htbl->size; i++) { - struct rhash_head *pos; + if (s_num > 1) + goto mc_list; - rht_for_each_entry_rcu(nlsk, pos, htbl, i, node) { - sk = (struct sock *)nlsk; + num--; - if (!net_eq(sock_net(sk), net)) - continue; - if (num < s_num) { - num++; + if (!hti) { + hti = kmalloc(sizeof(*hti), GFP_KERNEL); + if (!hti) + return -ENOMEM; + + cb->args[2] = (long)hti; + } + + if (!s_num) + rhashtable_walk_enter(&tbl->hash, hti); + + ret = rhashtable_walk_start(hti); + if (ret == -EAGAIN) + ret = 0; + if (ret) + goto stop; + + while ((nlsk = rhashtable_walk_next(hti))) { + if (IS_ERR(nlsk)) { + ret = PTR_ERR(nlsk); + if (ret == -EAGAIN) { + ret = 0; continue; } + break; + } - if (sk_diag_fill(sk, skb, req, - NETLINK_CB(cb->skb).portid, - cb->nlh->nlmsg_seq, - NLM_F_MULTI, - sock_i_ino(sk)) < 0) { - ret = 1; - goto done; - } + sk = (struct sock *)nlsk; - num++; + if (!net_eq(sock_net(sk), net)) + continue; + + if (sk_diag_fill(sk, skb, req, + NETLINK_CB(cb->skb).portid, + cb->nlh->nlmsg_seq, + NLM_F_MULTI, + sock_i_ino(sk)) < 0) { + ret = 1; + break; } } +stop: + rhashtable_walk_stop(hti); + if (ret) + goto done; + + rhashtable_walk_exit(hti); + cb->args[2] = 0; + num++; + +mc_list: + read_lock(&nl_table_lock); sk_for_each_bound(sk, &tbl->mc_list) { if (sk_hashed(sk)) continue; @@ -116,13 +148,14 @@ static int __netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb, NLM_F_MULTI, sock_i_ino(sk)) < 0) { ret = 1; - goto done; + break; } num++; } + read_unlock(&nl_table_lock); + done: cb->args[0] = num; - cb->args[1] = protocol; return ret; } @@ -131,20 +164,20 @@ static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) { struct netlink_diag_req *req; int s_num = cb->args[0]; + int err = 0; req = nlmsg_data(cb->nlh); - rcu_read_lock(); - read_lock(&nl_table_lock); - if (req->sdiag_protocol == NDIAG_PROTO_ALL) { int i; for (i = cb->args[1]; i < MAX_LINKS; i++) { - if (__netlink_diag_dump(skb, cb, i, s_num)) + err = __netlink_diag_dump(skb, cb, i, s_num); + if (err) break; s_num = 0; } + cb->args[1] = i; } else { if (req->sdiag_protocol >= MAX_LINKS) { read_unlock(&nl_table_lock); @@ -152,13 +185,22 @@ static int netlink_diag_dump(struct sk_buff *skb, struct netlink_callback *cb) return -ENOENT; } - __netlink_diag_dump(skb, cb, req->sdiag_protocol, s_num); + err = __netlink_diag_dump(skb, cb, req->sdiag_protocol, s_num); } - read_unlock(&nl_table_lock); - rcu_read_unlock(); + return err < 0 ? err : skb->len; +} + +static int netlink_diag_dump_done(struct netlink_callback *cb) +{ + struct rhashtable_iter *hti = (void *)cb->args[2]; + + if (cb->args[0] == 1) + rhashtable_walk_exit(hti); - return skb->len; + kfree(hti); + + return 0; } static int netlink_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h) @@ -172,6 +214,7 @@ static int netlink_diag_handler_dump(struct sk_buff *skb, struct nlmsghdr *h) if (h->nlmsg_flags & NLM_F_DUMP) { struct netlink_dump_control c = { .dump = netlink_diag_dump, + .done = netlink_diag_dump_done, }; return netlink_dump_start(net->diag_nlsk, skb, h, &c); } else -- 2.20.1