From 067a7cd06f7bf860f2e3415394b065b9a0983802 Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Mon, 20 Jun 2016 13:37:18 -0700 Subject: act_ife: only acquire tcf_lock for existing actions Alexey reported that we have GFP_KERNEL allocation when holding the spinlock tcf_lock. Actually we don't have to take that spinlock for all the cases, especially for the new one we just create. To modify the existing actions, we still need this spinlock to make sure the whole update is atomic. For net-next, we can get rid of this spinlock because we already hold the RTNL lock on slow path, and on fast path we can use RCU to protect the metalist. Joint work with Jamal. Reported-by: Alexey Khoroshilov Cc: Jamal Hadi Salim Signed-off-by: Cong Wang Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- net/sched/act_ife.c | 55 ++++++++++++++++++++++++++++++----------------------- 1 file changed, 31 insertions(+), 24 deletions(-) (limited to 'net') diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c index 658046dfe02d..e4076598f214 100644 --- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -106,9 +106,9 @@ int ife_get_meta_u16(struct sk_buff *skb, struct tcf_meta_info *mi) } EXPORT_SYMBOL_GPL(ife_get_meta_u16); -int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval) +int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval, gfp_t gfp) { - mi->metaval = kmemdup(metaval, sizeof(u32), GFP_KERNEL); + mi->metaval = kmemdup(metaval, sizeof(u32), gfp); if (!mi->metaval) return -ENOMEM; @@ -116,9 +116,9 @@ int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval) } EXPORT_SYMBOL_GPL(ife_alloc_meta_u32); -int ife_alloc_meta_u16(struct tcf_meta_info *mi, void *metaval) +int ife_alloc_meta_u16(struct tcf_meta_info *mi, void *metaval, gfp_t gfp) { - mi->metaval = kmemdup(metaval, sizeof(u16), GFP_KERNEL); + mi->metaval = kmemdup(metaval, sizeof(u16), gfp); if (!mi->metaval) return -ENOMEM; @@ -240,10 +240,10 @@ static int ife_validate_metatype(struct tcf_meta_ops *ops, void *val, int len) } /* called when adding new meta information - * under ife->tcf_lock + * under ife->tcf_lock for existing action */ static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid, - void *val, int len) + void *val, int len, bool exists) { struct tcf_meta_ops *ops = find_ife_oplist(metaid); int ret = 0; @@ -251,11 +251,13 @@ static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid, if (!ops) { ret = -ENOENT; #ifdef CONFIG_MODULES - spin_unlock_bh(&ife->tcf_lock); + if (exists) + spin_unlock_bh(&ife->tcf_lock); rtnl_unlock(); request_module("ifemeta%u", metaid); rtnl_lock(); - spin_lock_bh(&ife->tcf_lock); + if (exists) + spin_lock_bh(&ife->tcf_lock); ops = find_ife_oplist(metaid); #endif } @@ -272,10 +274,10 @@ static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid, } /* called when adding new meta information - * under ife->tcf_lock + * under ife->tcf_lock for existing action */ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, - int len) + int len, bool exists) { struct tcf_meta_info *mi = NULL; struct tcf_meta_ops *ops = find_ife_oplist(metaid); @@ -284,7 +286,7 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, if (!ops) return -ENOENT; - mi = kzalloc(sizeof(*mi), GFP_KERNEL); + mi = kzalloc(sizeof(*mi), exists ? GFP_ATOMIC : GFP_KERNEL); if (!mi) { /*put back what find_ife_oplist took */ module_put(ops->owner); @@ -294,7 +296,7 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, mi->metaid = metaid; mi->ops = ops; if (len > 0) { - ret = ops->alloc(mi, metaval); + ret = ops->alloc(mi, metaval, exists ? GFP_ATOMIC : GFP_KERNEL); if (ret != 0) { kfree(mi); module_put(ops->owner); @@ -307,14 +309,14 @@ static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval, 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; int installed = 0; list_for_each_entry(o, &ifeoplist, list) { - rc = add_metainfo(ife, o->metaid, NULL, 0); + rc = add_metainfo(ife, o->metaid, NULL, 0, exists); if (rc == 0) installed += 1; } @@ -385,8 +387,9 @@ static void tcf_ife_cleanup(struct tc_action *a, int bind) spin_unlock_bh(&ife->tcf_lock); } -/* under ife->tcf_lock */ -static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb) +/* under ife->tcf_lock for existing action */ +static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb, + bool exists) { int len = 0; int rc = 0; @@ -398,11 +401,11 @@ 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); + rc = load_metaops_and_vet(ife, i, val, len, exists); if (rc != 0) return rc; - rc = add_metainfo(ife, i, val, len); + rc = add_metainfo(ife, i, val, len, exists); if (rc) return rc; } @@ -474,7 +477,8 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla, saddr = nla_data(tb[TCA_IFE_SMAC]); } - spin_lock_bh(&ife->tcf_lock); + if (exists) + spin_lock_bh(&ife->tcf_lock); ife->tcf_action = parm->action; if (parm->flags & IFE_ENCODE) { @@ -504,11 +508,12 @@ metadata_parse_err: if (ret == ACT_P_CREATED) _tcf_ife_cleanup(a, bind); - spin_unlock_bh(&ife->tcf_lock); + if (exists) + spin_unlock_bh(&ife->tcf_lock); return err; } - err = populate_metalist(ife, tb2); + err = populate_metalist(ife, tb2, exists); if (err) goto metadata_parse_err; @@ -518,17 +523,19 @@ 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); - spin_unlock_bh(&ife->tcf_lock); + if (exists) + spin_unlock_bh(&ife->tcf_lock); return err; } } - spin_unlock_bh(&ife->tcf_lock); + if (exists) + spin_unlock_bh(&ife->tcf_lock); if (ret == ACT_P_CREATED) tcf_hash_insert(tn, a); -- cgit v1.2.3