diff options
Diffstat (limited to 'net/sched/cls_api.c')
-rw-r--r-- | net/sched/cls_api.c | 250 |
1 files changed, 180 insertions, 70 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index 0a75cb2e5e7b..43c8559aca56 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -240,8 +240,8 @@ static void tcf_chain_destroy(struct tcf_chain *chain) if (!chain->index) block->chain0.chain = NULL; kfree(chain); - if (list_empty(&block->chain_list) && block->refcnt == 0) - kfree(block); + if (list_empty(&block->chain_list) && !refcount_read(&block->refcnt)) + kfree_rcu(block, rcu); } static void tcf_chain_hold(struct tcf_chain *chain) @@ -473,6 +473,7 @@ tcf_chain0_head_change_cb_del(struct tcf_block *block, } struct tcf_net { + spinlock_t idr_lock; /* Protects idr */ struct idr idr; }; @@ -482,16 +483,25 @@ static int tcf_block_insert(struct tcf_block *block, struct net *net, struct netlink_ext_ack *extack) { struct tcf_net *tn = net_generic(net, tcf_net_id); + int err; + + idr_preload(GFP_KERNEL); + spin_lock(&tn->idr_lock); + err = idr_alloc_u32(&tn->idr, block, &block->index, block->index, + GFP_NOWAIT); + spin_unlock(&tn->idr_lock); + idr_preload_end(); - return idr_alloc_u32(&tn->idr, block, &block->index, block->index, - GFP_KERNEL); + return err; } static void tcf_block_remove(struct tcf_block *block, struct net *net) { struct tcf_net *tn = net_generic(net, tcf_net_id); + spin_lock(&tn->idr_lock); idr_remove(&tn->idr, block->index); + spin_unlock(&tn->idr_lock); } static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q, @@ -510,7 +520,7 @@ static struct tcf_block *tcf_block_create(struct net *net, struct Qdisc *q, INIT_LIST_HEAD(&block->owner_list); INIT_LIST_HEAD(&block->chain0.filter_chain_list); - block->refcnt = 1; + refcount_set(&block->refcnt, 1); block->net = net; block->index = block_index; @@ -527,6 +537,78 @@ static struct tcf_block *tcf_block_lookup(struct net *net, u32 block_index) return idr_find(&tn->idr, block_index); } +static struct tcf_block *tcf_block_refcnt_get(struct net *net, u32 block_index) +{ + struct tcf_block *block; + + rcu_read_lock(); + block = tcf_block_lookup(net, block_index); + if (block && !refcount_inc_not_zero(&block->refcnt)) + block = NULL; + rcu_read_unlock(); + + return block; +} + +static void tcf_block_flush_all_chains(struct tcf_block *block) +{ + struct tcf_chain *chain; + + /* Hold a refcnt for all chains, so that they don't disappear + * while we are iterating. + */ + list_for_each_entry(chain, &block->chain_list, list) + tcf_chain_hold(chain); + + list_for_each_entry(chain, &block->chain_list, list) + tcf_chain_flush(chain); +} + +static void tcf_block_put_all_chains(struct tcf_block *block) +{ + struct tcf_chain *chain, *tmp; + + /* At this point, all the chains should have refcnt >= 1. */ + list_for_each_entry_safe(chain, tmp, &block->chain_list, list) { + tcf_chain_put_explicitly_created(chain); + tcf_chain_put(chain); + } +} + +static void __tcf_block_put(struct tcf_block *block, struct Qdisc *q, + struct tcf_block_ext_info *ei) +{ + if (refcount_dec_and_test(&block->refcnt)) { + /* Flushing/putting all chains will cause the block to be + * deallocated when last chain is freed. However, if chain_list + * is empty, block has to be manually deallocated. After block + * reference counter reached 0, it is no longer possible to + * increment it or add new chains to block. + */ + bool free_block = list_empty(&block->chain_list); + + if (tcf_block_shared(block)) + tcf_block_remove(block, block->net); + if (!free_block) + tcf_block_flush_all_chains(block); + + if (q) + tcf_block_offload_unbind(block, q, ei); + + if (free_block) + kfree_rcu(block, rcu); + else + tcf_block_put_all_chains(block); + } else if (q) { + tcf_block_offload_unbind(block, q, ei); + } +} + +static void tcf_block_refcnt_put(struct tcf_block *block) +{ + __tcf_block_put(block, NULL, NULL); +} + /* Find tcf block. * Set q, parent, cl when appropriate. */ @@ -537,9 +619,10 @@ static struct tcf_block *tcf_block_find(struct net *net, struct Qdisc **q, struct netlink_ext_ack *extack) { struct tcf_block *block; + int err = 0; if (ifindex == TCM_IFINDEX_MAGIC_BLOCK) { - block = tcf_block_lookup(net, block_index); + block = tcf_block_refcnt_get(net, block_index); if (!block) { NL_SET_ERR_MSG(extack, "Block of given index was not found"); return ERR_PTR(-EINVAL); @@ -548,55 +631,106 @@ static struct tcf_block *tcf_block_find(struct net *net, struct Qdisc **q, const struct Qdisc_class_ops *cops; struct net_device *dev; + rcu_read_lock(); + /* Find link */ - dev = __dev_get_by_index(net, ifindex); - if (!dev) + dev = dev_get_by_index_rcu(net, ifindex); + if (!dev) { + rcu_read_unlock(); return ERR_PTR(-ENODEV); + } /* Find qdisc */ if (!*parent) { *q = dev->qdisc; *parent = (*q)->handle; } else { - *q = qdisc_lookup(dev, TC_H_MAJ(*parent)); + *q = qdisc_lookup_rcu(dev, TC_H_MAJ(*parent)); if (!*q) { NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists"); - return ERR_PTR(-EINVAL); + err = -EINVAL; + goto errout_rcu; } } + *q = qdisc_refcount_inc_nz(*q); + if (!*q) { + NL_SET_ERR_MSG(extack, "Parent Qdisc doesn't exists"); + err = -EINVAL; + goto errout_rcu; + } + /* Is it classful? */ cops = (*q)->ops->cl_ops; if (!cops) { NL_SET_ERR_MSG(extack, "Qdisc not classful"); - return ERR_PTR(-EINVAL); + err = -EINVAL; + goto errout_rcu; } if (!cops->tcf_block) { NL_SET_ERR_MSG(extack, "Class doesn't support blocks"); - return ERR_PTR(-EOPNOTSUPP); + err = -EOPNOTSUPP; + goto errout_rcu; } + /* At this point we know that qdisc is not noop_qdisc, + * which means that qdisc holds a reference to net_device + * and we hold a reference to qdisc, so it is safe to release + * rcu read lock. + */ + rcu_read_unlock(); + /* Do we search for filter, attached to class? */ if (TC_H_MIN(*parent)) { *cl = cops->find(*q, *parent); if (*cl == 0) { NL_SET_ERR_MSG(extack, "Specified class doesn't exist"); - return ERR_PTR(-ENOENT); + err = -ENOENT; + goto errout_qdisc; } } /* And the last stroke */ block = cops->tcf_block(*q, *cl, extack); - if (!block) - return ERR_PTR(-EINVAL); + if (!block) { + err = -EINVAL; + goto errout_qdisc; + } if (tcf_block_shared(block)) { NL_SET_ERR_MSG(extack, "This filter block is shared. Please use the block index to manipulate the filters"); - return ERR_PTR(-EOPNOTSUPP); + err = -EOPNOTSUPP; + goto errout_qdisc; } + + /* Always take reference to block in order to support execution + * of rules update path of cls API without rtnl lock. Caller + * must release block when it is finished using it. 'if' block + * of this conditional obtain reference to block by calling + * tcf_block_refcnt_get(). + */ + refcount_inc(&block->refcnt); } return block; + +errout_rcu: + rcu_read_unlock(); +errout_qdisc: + if (*q) { + qdisc_put(*q); + *q = NULL; + } + return ERR_PTR(err); +} + +static void tcf_block_release(struct Qdisc *q, struct tcf_block *block) +{ + if (!IS_ERR_OR_NULL(block)) + tcf_block_refcnt_put(block); + + if (q) + qdisc_put(q); } struct tcf_block_owner_item { @@ -664,21 +798,16 @@ int tcf_block_get_ext(struct tcf_block **p_block, struct Qdisc *q, { struct net *net = qdisc_net(q); struct tcf_block *block = NULL; - bool created = false; int err; - if (ei->block_index) { + if (ei->block_index) /* block_index not 0 means the shared block is requested */ - block = tcf_block_lookup(net, ei->block_index); - if (block) - block->refcnt++; - } + block = tcf_block_refcnt_get(net, ei->block_index); if (!block) { block = tcf_block_create(net, q, ei->block_index, extack); if (IS_ERR(block)) return PTR_ERR(block); - created = true; if (tcf_block_shared(block)) { err = tcf_block_insert(block, net, extack); if (err) @@ -708,14 +837,8 @@ err_block_offload_bind: err_chain0_head_change_cb_add: tcf_block_owner_del(block, q, ei->binder_type); err_block_owner_add: - if (created) { - if (tcf_block_shared(block)) - tcf_block_remove(block, net); err_block_insert: - kfree(block); - } else { - block->refcnt--; - } + tcf_block_refcnt_put(block); return err; } EXPORT_SYMBOL(tcf_block_get_ext); @@ -747,42 +870,12 @@ EXPORT_SYMBOL(tcf_block_get); void tcf_block_put_ext(struct tcf_block *block, struct Qdisc *q, struct tcf_block_ext_info *ei) { - struct tcf_chain *chain, *tmp; - if (!block) return; tcf_chain0_head_change_cb_del(block, ei); tcf_block_owner_del(block, q, ei->binder_type); - if (block->refcnt == 1) { - if (tcf_block_shared(block)) - tcf_block_remove(block, block->net); - - /* Hold a refcnt for all chains, so that they don't disappear - * while we are iterating. - */ - list_for_each_entry(chain, &block->chain_list, list) - tcf_chain_hold(chain); - - list_for_each_entry(chain, &block->chain_list, list) - tcf_chain_flush(chain); - } - - tcf_block_offload_unbind(block, q, ei); - - if (block->refcnt == 1) { - /* At this point, all the chains should have refcnt >= 1. */ - list_for_each_entry_safe(chain, tmp, &block->chain_list, list) { - tcf_chain_put_explicitly_created(chain); - tcf_chain_put(chain); - } - - block->refcnt--; - if (list_empty(&block->chain_list)) - kfree(block); - } else { - block->refcnt--; - } + __tcf_block_put(block, q, ei); } EXPORT_SYMBOL(tcf_block_put_ext); @@ -1332,6 +1425,7 @@ replay: errout: if (chain) tcf_chain_put(chain); + tcf_block_release(q, block); if (err == -EAGAIN) /* Replay the request. */ goto replay; @@ -1453,6 +1547,7 @@ static int tc_del_tfilter(struct sk_buff *skb, struct nlmsghdr *n, errout: if (chain) tcf_chain_put(chain); + tcf_block_release(q, block); return err; } @@ -1538,6 +1633,7 @@ static int tc_get_tfilter(struct sk_buff *skb, struct nlmsghdr *n, errout: if (chain) tcf_chain_put(chain); + tcf_block_release(q, block); return err; } @@ -1631,12 +1727,13 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) if (nlmsg_len(cb->nlh) < sizeof(*tcm)) return skb->len; - err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, NULL); + err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, + cb->extack); if (err) return err; if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) { - block = tcf_block_lookup(net, tcm->tcm_block_index); + block = tcf_block_refcnt_get(net, tcm->tcm_block_index); if (!block) goto out; /* If we work with block index, q is NULL and parent value @@ -1695,6 +1792,8 @@ static int tc_dump_tfilter(struct sk_buff *skb, struct netlink_callback *cb) } } + if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) + tcf_block_refcnt_put(block); cb->args[0] = index; out: @@ -1854,7 +1953,8 @@ replay: chain_index = tca[TCA_CHAIN] ? nla_get_u32(tca[TCA_CHAIN]) : 0; if (chain_index > TC_ACT_EXT_VAL_MASK) { NL_SET_ERR_MSG(extack, "Specified chain index exceeds upper limit"); - return -EINVAL; + err = -EINVAL; + goto errout_block; } chain = tcf_chain_lookup(block, chain_index); if (n->nlmsg_type == RTM_NEWCHAIN) { @@ -1866,23 +1966,27 @@ replay: tcf_chain_hold(chain); } else { NL_SET_ERR_MSG(extack, "Filter chain already exists"); - return -EEXIST; + err = -EEXIST; + goto errout_block; } } else { if (!(n->nlmsg_flags & NLM_F_CREATE)) { NL_SET_ERR_MSG(extack, "Need both RTM_NEWCHAIN and NLM_F_CREATE to create a new chain"); - return -ENOENT; + err = -ENOENT; + goto errout_block; } chain = tcf_chain_create(block, chain_index); if (!chain) { NL_SET_ERR_MSG(extack, "Failed to create filter chain"); - return -ENOMEM; + err = -ENOMEM; + goto errout_block; } } } else { if (!chain || tcf_chain_held_by_acts_only(chain)) { NL_SET_ERR_MSG(extack, "Cannot find specified filter chain"); - return -EINVAL; + err = -EINVAL; + goto errout_block; } tcf_chain_hold(chain); } @@ -1926,6 +2030,8 @@ replay: errout: tcf_chain_put(chain); +errout_block: + tcf_block_release(q, block); if (err == -EAGAIN) /* Replay the request. */ goto replay; @@ -1949,12 +2055,13 @@ static int tc_dump_chain(struct sk_buff *skb, struct netlink_callback *cb) if (nlmsg_len(cb->nlh) < sizeof(*tcm)) return skb->len; - err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, NULL); + err = nlmsg_parse(cb->nlh, sizeof(*tcm), tca, TCA_MAX, NULL, + cb->extack); if (err) return err; if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) { - block = tcf_block_lookup(net, tcm->tcm_block_index); + block = tcf_block_refcnt_get(net, tcm->tcm_block_index); if (!block) goto out; /* If we work with block index, q is NULL and parent value @@ -2021,6 +2128,8 @@ static int tc_dump_chain(struct sk_buff *skb, struct netlink_callback *cb) index++; } + if (tcm->tcm_ifindex == TCM_IFINDEX_MAGIC_BLOCK) + tcf_block_refcnt_put(block); cb->args[0] = index; out: @@ -2213,6 +2322,7 @@ static __net_init int tcf_net_init(struct net *net) { struct tcf_net *tn = net_generic(net, tcf_net_id); + spin_lock_init(&tn->idr_lock); idr_init(&tn->idr); return 0; } |