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-rw-r--r--target/linux/generic/patches-3.18/080-11-fib_trie-Push-rcu_read_lock-unlock-to-callers.patch403
1 files changed, 403 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.18/080-11-fib_trie-Push-rcu_read_lock-unlock-to-callers.patch b/target/linux/generic/patches-3.18/080-11-fib_trie-Push-rcu_read_lock-unlock-to-callers.patch
new file mode 100644
index 0000000..b36bcd8
--- /dev/null
+++ b/target/linux/generic/patches-3.18/080-11-fib_trie-Push-rcu_read_lock-unlock-to-callers.patch
@@ -0,0 +1,403 @@
+From: Alexander Duyck <alexander.h.duyck@redhat.com>
+Date: Wed, 31 Dec 2014 10:56:24 -0800
+Subject: [PATCH] fib_trie: Push rcu_read_lock/unlock to callers
+
+This change is to start cleaning up some of the rcu_read_lock/unlock
+handling. I realized while reviewing the code there are several spots that
+I don't believe are being handled correctly or are masking warnings by
+locally calling rcu_read_lock/unlock instead of calling them at the correct
+level.
+
+A common example is a call to fib_get_table followed by fib_table_lookup.
+The rcu_read_lock/unlock ought to wrap both but there are several spots where
+they were not wrapped.
+
+Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+
+--- a/include/net/ip_fib.h
++++ b/include/net/ip_fib.h
+@@ -222,16 +222,19 @@ static inline struct fib_table *fib_new_
+ static inline int fib_lookup(struct net *net, const struct flowi4 *flp,
+ struct fib_result *res)
+ {
+- struct fib_table *table;
++ int err = -ENETUNREACH;
+
+- table = fib_get_table(net, RT_TABLE_LOCAL);
+- if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
+- return 0;
+-
+- table = fib_get_table(net, RT_TABLE_MAIN);
+- if (!fib_table_lookup(table, flp, res, FIB_LOOKUP_NOREF))
+- return 0;
+- return -ENETUNREACH;
++ rcu_read_lock();
++
++ if (!fib_table_lookup(fib_get_table(net, RT_TABLE_LOCAL), flp, res,
++ FIB_LOOKUP_NOREF) ||
++ !fib_table_lookup(fib_get_table(net, RT_TABLE_MAIN), flp, res,
++ FIB_LOOKUP_NOREF))
++ err = 0;
++
++ rcu_read_unlock();
++
++ return err;
+ }
+
+ #else /* CONFIG_IP_MULTIPLE_TABLES */
+@@ -247,20 +250,25 @@ static inline int fib_lookup(struct net
+ struct fib_result *res)
+ {
+ if (!net->ipv4.fib_has_custom_rules) {
++ int err = -ENETUNREACH;
++
++ rcu_read_lock();
++
+ res->tclassid = 0;
+- if (net->ipv4.fib_local &&
+- !fib_table_lookup(net->ipv4.fib_local, flp, res,
+- FIB_LOOKUP_NOREF))
+- return 0;
+- if (net->ipv4.fib_main &&
+- !fib_table_lookup(net->ipv4.fib_main, flp, res,
+- FIB_LOOKUP_NOREF))
+- return 0;
+- if (net->ipv4.fib_default &&
+- !fib_table_lookup(net->ipv4.fib_default, flp, res,
+- FIB_LOOKUP_NOREF))
+- return 0;
+- return -ENETUNREACH;
++ if ((net->ipv4.fib_local &&
++ !fib_table_lookup(net->ipv4.fib_local, flp, res,
++ FIB_LOOKUP_NOREF)) ||
++ (net->ipv4.fib_main &&
++ !fib_table_lookup(net->ipv4.fib_main, flp, res,
++ FIB_LOOKUP_NOREF)) ||
++ (net->ipv4.fib_default &&
++ !fib_table_lookup(net->ipv4.fib_default, flp, res,
++ FIB_LOOKUP_NOREF)))
++ err = 0;
++
++ rcu_read_unlock();
++
++ return err;
+ }
+ return __fib_lookup(net, flp, res);
+ }
+--- a/net/ipv4/fib_frontend.c
++++ b/net/ipv4/fib_frontend.c
+@@ -109,6 +109,7 @@ struct fib_table *fib_new_table(struct n
+ return tb;
+ }
+
++/* caller must hold either rtnl or rcu read lock */
+ struct fib_table *fib_get_table(struct net *net, u32 id)
+ {
+ struct fib_table *tb;
+@@ -119,15 +120,11 @@ struct fib_table *fib_get_table(struct n
+ id = RT_TABLE_MAIN;
+ h = id & (FIB_TABLE_HASHSZ - 1);
+
+- rcu_read_lock();
+ head = &net->ipv4.fib_table_hash[h];
+ hlist_for_each_entry_rcu(tb, head, tb_hlist) {
+- if (tb->tb_id == id) {
+- rcu_read_unlock();
++ if (tb->tb_id == id)
+ return tb;
+- }
+ }
+- rcu_read_unlock();
+ return NULL;
+ }
+ #endif /* CONFIG_IP_MULTIPLE_TABLES */
+@@ -167,16 +164,18 @@ static inline unsigned int __inet_dev_ad
+ if (ipv4_is_multicast(addr))
+ return RTN_MULTICAST;
+
++ rcu_read_lock();
++
+ local_table = fib_get_table(net, RT_TABLE_LOCAL);
+ if (local_table) {
+ ret = RTN_UNICAST;
+- rcu_read_lock();
+ if (!fib_table_lookup(local_table, &fl4, &res, FIB_LOOKUP_NOREF)) {
+ if (!dev || dev == res.fi->fib_dev)
+ ret = res.type;
+ }
+- rcu_read_unlock();
+ }
++
++ rcu_read_unlock();
+ return ret;
+ }
+
+@@ -919,7 +918,7 @@ void fib_del_ifaddr(struct in_ifaddr *if
+ #undef BRD1_OK
+ }
+
+-static void nl_fib_lookup(struct fib_result_nl *frn, struct fib_table *tb)
++static void nl_fib_lookup(struct net *net, struct fib_result_nl *frn)
+ {
+
+ struct fib_result res;
+@@ -929,6 +928,11 @@ static void nl_fib_lookup(struct fib_res
+ .flowi4_tos = frn->fl_tos,
+ .flowi4_scope = frn->fl_scope,
+ };
++ struct fib_table *tb;
++
++ rcu_read_lock();
++
++ tb = fib_get_table(net, frn->tb_id_in);
+
+ frn->err = -ENOENT;
+ if (tb) {
+@@ -945,6 +949,8 @@ static void nl_fib_lookup(struct fib_res
+ }
+ local_bh_enable();
+ }
++
++ rcu_read_unlock();
+ }
+
+ static void nl_fib_input(struct sk_buff *skb)
+@@ -952,7 +958,6 @@ static void nl_fib_input(struct sk_buff
+ struct net *net;
+ struct fib_result_nl *frn;
+ struct nlmsghdr *nlh;
+- struct fib_table *tb;
+ u32 portid;
+
+ net = sock_net(skb->sk);
+@@ -967,9 +972,7 @@ static void nl_fib_input(struct sk_buff
+ nlh = nlmsg_hdr(skb);
+
+ frn = (struct fib_result_nl *) nlmsg_data(nlh);
+- tb = fib_get_table(net, frn->tb_id_in);
+-
+- nl_fib_lookup(frn, tb);
++ nl_fib_lookup(net, frn);
+
+ portid = NETLINK_CB(skb).portid; /* netlink portid */
+ NETLINK_CB(skb).portid = 0; /* from kernel */
+--- a/net/ipv4/fib_rules.c
++++ b/net/ipv4/fib_rules.c
+@@ -81,27 +81,25 @@ static int fib4_rule_action(struct fib_r
+ break;
+
+ case FR_ACT_UNREACHABLE:
+- err = -ENETUNREACH;
+- goto errout;
++ return -ENETUNREACH;
+
+ case FR_ACT_PROHIBIT:
+- err = -EACCES;
+- goto errout;
++ return -EACCES;
+
+ case FR_ACT_BLACKHOLE:
+ default:
+- err = -EINVAL;
+- goto errout;
++ return -EINVAL;
+ }
+
++ rcu_read_lock();
++
+ tbl = fib_get_table(rule->fr_net, rule->table);
+- if (!tbl)
+- goto errout;
++ if (tbl)
++ err = fib_table_lookup(tbl, &flp->u.ip4,
++ (struct fib_result *)arg->result,
++ arg->flags);
+
+- err = fib_table_lookup(tbl, &flp->u.ip4, (struct fib_result *) arg->result, arg->flags);
+- if (err > 0)
+- err = -EAGAIN;
+-errout:
++ rcu_read_unlock();
+ return err;
+ }
+
+--- a/net/ipv4/fib_trie.c
++++ b/net/ipv4/fib_trie.c
+@@ -1181,72 +1181,6 @@ err:
+ return err;
+ }
+
+-/* should be called with rcu_read_lock */
+-static int check_leaf(struct fib_table *tb, struct trie *t, struct tnode *l,
+- t_key key, const struct flowi4 *flp,
+- struct fib_result *res, int fib_flags)
+-{
+- struct leaf_info *li;
+- struct hlist_head *hhead = &l->list;
+-
+- hlist_for_each_entry_rcu(li, hhead, hlist) {
+- struct fib_alias *fa;
+-
+- if (l->key != (key & li->mask_plen))
+- continue;
+-
+- list_for_each_entry_rcu(fa, &li->falh, fa_list) {
+- struct fib_info *fi = fa->fa_info;
+- int nhsel, err;
+-
+- if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
+- continue;
+- if (fi->fib_dead)
+- continue;
+- if (fa->fa_info->fib_scope < flp->flowi4_scope)
+- continue;
+- fib_alias_accessed(fa);
+- err = fib_props[fa->fa_type].error;
+- if (unlikely(err < 0)) {
+-#ifdef CONFIG_IP_FIB_TRIE_STATS
+- this_cpu_inc(t->stats->semantic_match_passed);
+-#endif
+- return err;
+- }
+- if (fi->fib_flags & RTNH_F_DEAD)
+- continue;
+- for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
+- const struct fib_nh *nh = &fi->fib_nh[nhsel];
+-
+- if (nh->nh_flags & RTNH_F_DEAD)
+- continue;
+- if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)
+- continue;
+-
+-#ifdef CONFIG_IP_FIB_TRIE_STATS
+- this_cpu_inc(t->stats->semantic_match_passed);
+-#endif
+- res->prefixlen = li->plen;
+- res->nh_sel = nhsel;
+- res->type = fa->fa_type;
+- res->scope = fi->fib_scope;
+- res->fi = fi;
+- res->table = tb;
+- res->fa_head = &li->falh;
+- if (!(fib_flags & FIB_LOOKUP_NOREF))
+- atomic_inc(&fi->fib_clntref);
+- return 0;
+- }
+- }
+-
+-#ifdef CONFIG_IP_FIB_TRIE_STATS
+- this_cpu_inc(t->stats->semantic_match_miss);
+-#endif
+- }
+-
+- return 1;
+-}
+-
+ static inline t_key prefix_mismatch(t_key key, struct tnode *n)
+ {
+ t_key prefix = n->key;
+@@ -1254,6 +1188,7 @@ static inline t_key prefix_mismatch(t_ke
+ return (key ^ prefix) & (prefix | -prefix);
+ }
+
++/* should be called with rcu_read_lock */
+ int fib_table_lookup(struct fib_table *tb, const struct flowi4 *flp,
+ struct fib_result *res, int fib_flags)
+ {
+@@ -1263,14 +1198,12 @@ int fib_table_lookup(struct fib_table *t
+ #endif
+ const t_key key = ntohl(flp->daddr);
+ struct tnode *n, *pn;
++ struct leaf_info *li;
+ t_key cindex;
+- int ret = 1;
+-
+- rcu_read_lock();
+
+ n = rcu_dereference(t->trie);
+ if (!n)
+- goto failed;
++ return -EAGAIN;
+
+ #ifdef CONFIG_IP_FIB_TRIE_STATS
+ this_cpu_inc(stats->gets);
+@@ -1350,7 +1283,7 @@ backtrace:
+
+ pn = node_parent_rcu(pn);
+ if (unlikely(!pn))
+- goto failed;
++ return -EAGAIN;
+ #ifdef CONFIG_IP_FIB_TRIE_STATS
+ this_cpu_inc(stats->backtrack);
+ #endif
+@@ -1368,12 +1301,62 @@ backtrace:
+
+ found:
+ /* Step 3: Process the leaf, if that fails fall back to backtracing */
+- ret = check_leaf(tb, t, n, key, flp, res, fib_flags);
+- if (unlikely(ret > 0))
+- goto backtrace;
+-failed:
+- rcu_read_unlock();
+- return ret;
++ hlist_for_each_entry_rcu(li, &n->list, hlist) {
++ struct fib_alias *fa;
++
++ if ((key ^ n->key) & li->mask_plen)
++ continue;
++
++ list_for_each_entry_rcu(fa, &li->falh, fa_list) {
++ struct fib_info *fi = fa->fa_info;
++ int nhsel, err;
++
++ if (fa->fa_tos && fa->fa_tos != flp->flowi4_tos)
++ continue;
++ if (fi->fib_dead)
++ continue;
++ if (fa->fa_info->fib_scope < flp->flowi4_scope)
++ continue;
++ fib_alias_accessed(fa);
++ err = fib_props[fa->fa_type].error;
++ if (unlikely(err < 0)) {
++#ifdef CONFIG_IP_FIB_TRIE_STATS
++ this_cpu_inc(stats->semantic_match_passed);
++#endif
++ return err;
++ }
++ if (fi->fib_flags & RTNH_F_DEAD)
++ continue;
++ for (nhsel = 0; nhsel < fi->fib_nhs; nhsel++) {
++ const struct fib_nh *nh = &fi->fib_nh[nhsel];
++
++ if (nh->nh_flags & RTNH_F_DEAD)
++ continue;
++ if (flp->flowi4_oif && flp->flowi4_oif != nh->nh_oif)
++ continue;
++
++ if (!(fib_flags & FIB_LOOKUP_NOREF))
++ atomic_inc(&fi->fib_clntref);
++
++ res->prefixlen = li->plen;
++ res->nh_sel = nhsel;
++ res->type = fa->fa_type;
++ res->scope = fi->fib_scope;
++ res->fi = fi;
++ res->table = tb;
++ res->fa_head = &li->falh;
++#ifdef CONFIG_IP_FIB_TRIE_STATS
++ this_cpu_inc(stats->semantic_match_passed);
++#endif
++ return err;
++ }
++ }
++
++#ifdef CONFIG_IP_FIB_TRIE_STATS
++ this_cpu_inc(stats->semantic_match_miss);
++#endif
++ }
++ goto backtrace;
+ }
+ EXPORT_SYMBOL_GPL(fib_table_lookup);
+
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