The only time we need to take tcfa_lock is when adding
a new metainfo to an existing ife->metalist. We don't need
to take tcfa_lock so early and so broadly in tcf_ife_init().
This means we can always take ife_mod_lock first, avoid the
reverse locking ordering warning as reported by Vlad.
Reported-by: Vlad Buslov <vla...@mellanox.com>
Tested-by: Vlad Buslov <vla...@mellanox.com>
Cc: Vlad Buslov <vla...@mellanox.com>
Cc: Jamal Hadi Salim <j...@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangc...@gmail.com>
---
net/sched/act_ife.c | 38 +++++++++++++-------------------------
1 file changed, 13 insertions(+), 25 deletions(-)
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 9decbb74b3ac..244a8cf48183 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -265,11 +265,8 @@ static const char *ife_meta_id2name(u32 metaid)
#endif
/* called when adding new meta information
- * under ife->tcf_lock for existing action
*/
-static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,
- void *val, int len, bool exists,
- bool rtnl_held)
+static int load_metaops_and_vet(u32 metaid, void *val, int len, bool rtnl_held)
{
struct tcf_meta_ops *ops = find_ife_oplist(metaid);
int ret = 0;
@@ -277,15 +274,11 @@ static int load_metaops_and_vet(struct tcf_ife_info *ife,
u32 metaid,
if (!ops) {
ret = -ENOENT;
#ifdef CONFIG_MODULES
- if (exists)
- spin_unlock_bh(&ife->tcf_lock);
if (rtnl_held)
rtnl_unlock();
request_module("ife-meta-%s", ife_meta_id2name(metaid));
if (rtnl_held)
rtnl_lock();
- if (exists)
- spin_lock_bh(&ife->tcf_lock);
ops = find_ife_oplist(metaid);
#endif
}
@@ -302,10 +295,9 @@ static int load_metaops_and_vet(struct tcf_ife_info *ife,
u32 metaid,
}
/* called when adding new meta information
- * under ife->tcf_lock for existing action
*/
static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
- int len, bool atomic)
+ int len, bool atomic, bool exists)
{
struct tcf_meta_info *mi = NULL;
struct tcf_meta_ops *ops = find_ife_oplist(metaid);
@@ -332,12 +324,16 @@ static int add_metainfo(struct tcf_ife_info *ife, u32
metaid, void *metaval,
}
}
+ if (exists)
+ spin_lock_bh(&ife->tcf_lock);
list_add_tail(&mi->metalist, &ife->metalist);
+ if (exists)
+ spin_unlock_bh(&ife->tcf_lock);
return ret;
}
-static int use_all_metadata(struct tcf_ife_info *ife)
+static int use_all_metadata(struct tcf_ife_info *ife, bool exists)
{
struct tcf_meta_ops *o;
int rc = 0;
@@ -345,7 +341,7 @@ static int use_all_metadata(struct tcf_ife_info *ife)
read_lock(&ife_mod_lock);
list_for_each_entry(o, &ifeoplist, list) {
- rc = add_metainfo(ife, o->metaid, NULL, 0, true);
+ rc = add_metainfo(ife, o->metaid, NULL, 0, true, exists);
if (rc == 0)
installed += 1;
}
@@ -422,7 +418,6 @@ static void tcf_ife_cleanup(struct tc_action *a)
kfree_rcu(p, rcu);
}
-/* under ife->tcf_lock for existing action */
static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,
bool exists, bool rtnl_held)
{
@@ -436,12 +431,11 @@ static int populate_metalist(struct tcf_ife_info *ife,
struct nlattr **tb,
val = nla_data(tb[i]);
len = nla_len(tb[i]);
- rc = load_metaops_and_vet(ife, i, val, len, exists,
- rtnl_held);
+ rc = load_metaops_and_vet(i, val, len, rtnl_held);
if (rc != 0)
return rc;
- rc = add_metainfo(ife, i, val, len, exists);
+ rc = add_metainfo(ife, i, val, len, false, exists);
if (rc)
return rc;
}
@@ -540,8 +534,6 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
p->eth_type = ife_type;
}
- if (exists)
- spin_lock_bh(&ife->tcf_lock);
if (ret == ACT_P_CREATED)
INIT_LIST_HEAD(&ife->metalist);
@@ -551,10 +543,7 @@ static int tcf_ife_init(struct net *net, struct nlattr
*nla,
NULL, NULL);
if (err) {
metadata_parse_err:
- if (exists)
- spin_unlock_bh(&ife->tcf_lock);
tcf_idr_release(*a, bind);
-
kfree(p);
return err;
}
@@ -569,17 +558,16 @@ static int tcf_ife_init(struct net *net, struct nlattr
*nla,
* as we can. You better have at least one else we are
* going to bail out
*/
- err = use_all_metadata(ife);
+ err = use_all_metadata(ife, exists);
if (err) {
- if (exists)
- spin_unlock_bh(&ife->tcf_lock);
tcf_idr_release(*a, bind);
-
kfree(p);
return err;
}
}
+ if (exists)
+ spin_lock_bh(&ife->tcf_lock);
ife->tcf_action = parm->action;
/* protected by tcf_lock when modifying existing action */
rcu_swap_protected(ife->params, p, 1);
--
2.14.4
