From f7a2ba5ab9c5e7cf9036ec68d3528ccdf9e81b0a Mon Sep 17 00:00:00 2001 From: Tom Herbert Date: Wed, 27 Jun 2018 14:38:59 -0700 Subject: [PATCH] ila: Fix use of rhashtable walk in ila_xlat.c Perform better EAGAIN handling, handle case where ila_dump_info fails and we missed objects in the dump, and add a skip index to skip over ila entires in a list on a rhashtable node that have already been visited (by a previous call to ila_nl_dump). Signed-off-by: Tom Herbert Signed-off-by: David S. Miller --- net/ipv6/ila/ila_xlat.c | 70 +++++++++++++++++++++++++++++++---------- 1 file changed, 54 insertions(+), 16 deletions(-) diff --git a/net/ipv6/ila/ila_xlat.c b/net/ipv6/ila/ila_xlat.c index 10ae13560b40..40f3f640e856 100644 --- a/net/ipv6/ila/ila_xlat.c +++ b/net/ipv6/ila/ila_xlat.c @@ -475,24 +475,31 @@ out_free: struct ila_dump_iter { struct rhashtable_iter rhiter; + int skip; }; static int ila_nl_dump_start(struct netlink_callback *cb) { struct net *net = sock_net(cb->skb->sk); struct ila_net *ilan = net_generic(net, ila_net_id); - struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0]; + struct ila_dump_iter *iter; + int ret; - if (!iter) { - iter = kmalloc(sizeof(*iter), GFP_KERNEL); - if (!iter) - return -ENOMEM; + iter = kmalloc(sizeof(*iter), GFP_KERNEL); + if (!iter) + return -ENOMEM; - cb->args[0] = (long)iter; + ret = rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter, + GFP_KERNEL); + if (ret) { + kfree(iter); + return ret; } - return rhashtable_walk_init(&ilan->rhash_table, &iter->rhiter, - GFP_KERNEL); + iter->skip = 0; + cb->args[0] = (long)iter; + + return ret; } static int ila_nl_dump_done(struct netlink_callback *cb) @@ -510,20 +517,45 @@ static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb) { struct ila_dump_iter *iter = (struct ila_dump_iter *)cb->args[0]; struct rhashtable_iter *rhiter = &iter->rhiter; + int skip = iter->skip; struct ila_map *ila; int ret; rhashtable_walk_start(rhiter); - for (;;) { - ila = rhashtable_walk_next(rhiter); + /* Get first entry */ + ila = rhashtable_walk_peek(rhiter); + + if (ila && !IS_ERR(ila) && skip) { + /* Skip over visited entries */ + + while (ila && skip) { + /* Skip over any ila entries in this list that we + * have already dumped. + */ + ila = rcu_access_pointer(ila->next); + skip--; + } + } + skip = 0; + + for (;;) { if (IS_ERR(ila)) { - if (PTR_ERR(ila) == -EAGAIN) - continue; ret = PTR_ERR(ila); - goto done; + if (ret == -EAGAIN) { + /* Table has changed and iter has reset. Return + * -EAGAIN to the application even if we have + * written data to the skb. The application + * needs to deal with this. + */ + + goto out_ret; + } else { + break; + } } else if (!ila) { + ret = 0; break; } @@ -532,15 +564,21 @@ static int ila_nl_dump(struct sk_buff *skb, struct netlink_callback *cb) cb->nlh->nlmsg_seq, NLM_F_MULTI, skb, ILA_CMD_GET); if (ret) - goto done; + goto out; + skip++; ila = rcu_access_pointer(ila->next); } + + skip = 0; + ila = rhashtable_walk_next(rhiter); } - ret = skb->len; +out: + iter->skip = skip; + ret = (skb->len ? : ret); -done: +out_ret: rhashtable_walk_stop(rhiter); return ret; } -- 2.30.2