4.14-stable review patch. If anyone has any objections, please let me know.
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From: Cong Wang xiyou.wangcong@gmail.com
[ Upstream commit 4e407ff5cd67ec76eeeea1deec227b7982dc7f66 ]
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 vladbu@mellanox.com Tested-by: Vlad Buslov vladbu@mellanox.com Cc: Vlad Buslov vladbu@mellanox.com Cc: Jamal Hadi Salim jhs@mojatatu.com Signed-off-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_ife.c | 37 +++++++++++++------------------------ 1 file changed, 13 insertions(+), 24 deletions(-)
--- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -249,10 +249,8 @@ static int ife_validate_metatype(struct }
/* 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) +static int load_metaops_and_vet(u32 metaid, void *val, int len) { struct tcf_meta_ops *ops = find_ife_oplist(metaid); int ret = 0; @@ -260,13 +258,9 @@ static int load_metaops_and_vet(struct t if (!ops) { ret = -ENOENT; #ifdef CONFIG_MODULES - if (exists) - spin_unlock_bh(&ife->tcf_lock); rtnl_unlock(); request_module("ifemeta%u", metaid); rtnl_lock(); - if (exists) - spin_lock_bh(&ife->tcf_lock); ops = find_ife_oplist(metaid); #endif } @@ -283,10 +277,9 @@ static int load_metaops_and_vet(struct t }
/* 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); @@ -313,12 +306,16 @@ static int add_metainfo(struct tcf_ife_i } }
+ 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; @@ -326,7 +323,7 @@ static int use_all_metadata(struct tcf_i
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; } @@ -398,7 +395,6 @@ static void tcf_ife_cleanup(struct tc_ac spin_unlock_bh(&ife->tcf_lock); }
-/* under ife->tcf_lock for existing action */ static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb, bool exists) { @@ -412,11 +408,11 @@ static int populate_metalist(struct tcf_ val = nla_data(tb[i]); len = nla_len(tb[i]);
- rc = load_metaops_and_vet(ife, i, val, len, exists); + rc = load_metaops_and_vet(i, val, len); 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; } @@ -481,6 +477,8 @@ static int tcf_ife_init(struct net *net, if (exists) spin_lock_bh(&ife->tcf_lock); ife->tcf_action = parm->action; + if (exists) + spin_unlock_bh(&ife->tcf_lock);
if (parm->flags & IFE_ENCODE) { if (daddr) @@ -508,9 +506,6 @@ metadata_parse_err: tcf_idr_release(*a, bind); if (ret == ACT_P_CREATED) _tcf_ife_cleanup(*a, bind); - - if (exists) - spin_unlock_bh(&ife->tcf_lock); return err; }
@@ -524,20 +519,14 @@ metadata_parse_err: * 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 (ret == ACT_P_CREATED) _tcf_ife_cleanup(*a, bind); - - if (exists) - spin_unlock_bh(&ife->tcf_lock); return err; } }
- if (exists) - spin_unlock_bh(&ife->tcf_lock); - if (ret == ACT_P_CREATED) tcf_idr_insert(tn, *a);