[PATCH net-next v2 00/15] Remove rtnl lock dependency from all action implementations

[PATCH net-next v2 00/15] Remove rtnl lock dependency from all action implementations

[Vlad Buslov]

Currently, all netlink protocol handlers for updating rules, actions and
qdiscs are protected with single global rtnl lock which removes any
possibility for parallelism. This patch set is a second step to remove
rtnl lock dependency from TC rules update path.

Recently, new rtnl registration flag RTNL_FLAG_DOIT_UNLOCKED was added.
Handlers registered with this flag are called without RTNL taken. End
goal is to have rule update handlers(RTM_NEWTFILTER, RTM_DELTFILTER,
etc.) to be registered with UNLOCKED flag to allow parallel execution.
However, there is no intention to completely remove or split rtnl lock
itself. This patch set addresses specific problems in implementation of
tc actions that prevent their control path from being executed
concurrently. Additional changes are required to refactor classifiers
API and individual classifiers for parallel execution. This patch set
lays groundwork to eventually register rule update handlers as
rtnl-unlocked.

Action API is already prepared for parallel execution with previous
patch set, which means that action ops that use action API for their
implementation do not require additional modifications. (delete, search,
etc.) Action API implements concurrency-safe reference counting and
guarantees that cleanup/delete is called only once, after last reference
to action is released.

The goal of this change is to update specific actions APIs that access
action private state directly, in order to be independent from external
locking. General approach is to re-use existing tcf_lock spinlock (used
by some action implementation to synchronize control path with data
path) to protect action private state from concurrent modification. If
action has rcu-protected pointer, tcf spinlock is used to protect its
update code, instead of relying on rtnl lock.

Some actions need to determine rtnl mutex status in order to release it.
For example, ife action can load additional kernel modules(meta ops) and
must make sure that no locks are held during module load. In such cases
'rtnl_held' argument is used to conditionally release rtnl mutex.

Changes from V1 to V2:
- Patch 12:
  - new patch
- Patch 14:
  - refactor gen_new_estimator() to reuse stats_lock when re-assigning
    rate estimator statistics pointer
- Remove mirred and tunnel_key helper function changes. (to be submitted
  and standalone patch)

Vlad Buslov (15):
  net: sched: act_bpf: remove dependency on rtnl lock
  net: sched: act_csum: remove dependency on rtnl lock
  net: sched: act_gact: remove dependency on rtnl lock
  net: sched: act_ife: remove dependency on rtnl lock
  net: sched: act_ipt: remove dependency on rtnl lock
  net: sched: act_pedit: remove dependency on rtnl lock
  net: sched: act_sample: remove dependency on rtnl lock
  net: sched: act_simple: remove dependency on rtnl lock
  net: sched: act_skbmod: remove dependency on rtnl lock
  net: sched: act_tunnel_key: remove dependency on rtnl lock
  net: sched: act_vlan: remove dependency on rtnl lock
  net: sched: extend action ops with put_dev callback
  net: sched: act_mirred: remove dependency on rtnl lock
  net: core: protect rate estimator statistics pointer with lock
  net: sched: act_police: remove dependency on rtnl lock

 include/net/act_api.h      |  1 +
 include/net/gen_stats.h    |  4 +--
 net/core/gen_estimator.c   | 21 ++++++-----
 net/sched/act_bpf.c        | 10 ++++--
 net/sched/act_csum.c       | 24 ++++++++-----
 net/sched/act_gact.c       | 10 ++++--
 net/sched/act_ife.c        | 40 +++++++++++++--------
 net/sched/act_ipt.c        |  3 ++
 net/sched/act_mirred.c     | 88 ++++++++++++++++++++++++++++++++--------------
 net/sched/act_pedit.c      | 40 ++++++++++-----------
 net/sched/act_police.c     |  9 +++--
 net/sched/act_sample.c     | 12 +++++--
 net/sched/act_simple.c     |  6 +++-
 net/sched/act_skbmod.c     | 14 +++++---
 net/sched/act_tunnel_key.c | 26 +++++++-------
 net/sched/act_vlan.c       | 27 +++++++-------
 net/sched/cls_api.c        |  1 +
 17 files changed, 214 insertions(+), 122 deletions(-)

-- 
2.7.5

[PATCH net-next v2 01/15] net: sched: act_bpf: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock to protect bpf action private data from concurrent
modification during dump and init. Remove rtnl lock assertion that is no
longer necessary.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_bpf.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 6203eb075c9a..9e8a33f9fee3 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -143,11 +143,12 @@ static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
 		.index   = prog->tcf_index,
 		.refcnt  = refcount_read(&prog->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&prog->tcf_bindcnt) - bind,
-		.action  = prog->tcf_action,
 	};
 	struct tcf_t tm;
 	int ret;
 
+	spin_lock(&prog->tcf_lock);
+	opt.action = prog->tcf_action;
 	if (nla_put(skb, TCA_ACT_BPF_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 
@@ -163,9 +164,11 @@ static int tcf_bpf_dump(struct sk_buff *skb, struct tc_action *act,
 			  TCA_ACT_BPF_PAD))
 		goto nla_put_failure;
 
+	spin_unlock(&prog->tcf_lock);
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&prog->tcf_lock);
 	nlmsg_trim(skb, tp);
 	return -1;
 }
@@ -264,7 +267,7 @@ static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
 {
 	cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
 	/* updates to prog->filter are prevented, since it's called either
-	 * with rtnl lock or during final cleanup in rcu callback
+	 * with tcf lock or during final cleanup in rcu callback
 	 */
 	cfg->filter = rcu_dereference_protected(prog->filter, 1);
 
@@ -336,8 +339,8 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 		goto out;
 
 	prog = to_bpf(*act);
-	ASSERT_RTNL();
 
+	spin_lock(&prog->tcf_lock);
 	if (res != ACT_P_CREATED)
 		tcf_bpf_prog_fill_cfg(prog, &old);
 
@@ -349,6 +352,7 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 
 	prog->tcf_action = parm->action;
 	rcu_assign_pointer(prog->filter, cfg.filter);
+	spin_unlock(&prog->tcf_lock);
 
 	if (res == ACT_P_CREATED) {
 		tcf_idr_insert(tn, *act);
-- 
2.7.5

[PATCH net-next v2 02/15] net: sched: act_csum: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf lock to protect csum action struct private data from concurrent
modification in init and dump. Use rcu swap operation to reassign params
pointer under protection of tcf lock. (old params value is not used by
init, so there is no need of standalone rcu dereference step)

Remove rtnl assertion that is no longer necessary.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_csum.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index 648a3a35b720..f01c59ba6d12 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -50,7 +50,7 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
 			 struct netlink_ext_ack *extack)
 {
 	struct tc_action_net *tn = net_generic(net, csum_net_id);
-	struct tcf_csum_params *params_old, *params_new;
+	struct tcf_csum_params *params_new;
 	struct nlattr *tb[TCA_CSUM_MAX + 1];
 	struct tc_csum *parm;
 	struct tcf_csum *p;
@@ -88,20 +88,22 @@ static int tcf_csum_init(struct net *net, struct nlattr *nla,
 	}
 
 	p = to_tcf_csum(*a);
-	ASSERT_RTNL();
 
 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
 	if (unlikely(!params_new)) {
 		tcf_idr_release(*a, bind);
 		return -ENOMEM;
 	}
-	params_old = rtnl_dereference(p->params);
+	params_new->update_flags = parm->update_flags;
 
+	spin_lock(&p->tcf_lock);
 	p->tcf_action = parm->action;
-	params_new->update_flags = parm->update_flags;
-	rcu_assign_pointer(p->params, params_new);
-	if (params_old)
-		kfree_rcu(params_old, rcu);
+	rcu_swap_protected(p->params, params_new,
+			   lockdep_is_held(&p->tcf_lock));
+	spin_unlock(&p->tcf_lock);
+
+	if (params_new)
+		kfree_rcu(params_new, rcu);
 
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
@@ -599,11 +601,13 @@ static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 		.index   = p->tcf_index,
 		.refcnt  = refcount_read(&p->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
-		.action  = p->tcf_action,
 	};
 	struct tcf_t t;
 
-	params = rtnl_dereference(p->params);
+	spin_lock(&p->tcf_lock);
+	params = rcu_dereference_protected(p->params,
+					   lockdep_is_held(&p->tcf_lock));
+	opt.action = p->tcf_action;
 	opt.update_flags = params->update_flags;
 
 	if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
@@ -612,10 +616,12 @@ static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 	tcf_tm_dump(&t, &p->tcf_tm);
 	if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
 		goto nla_put_failure;
+	spin_unlock(&p->tcf_lock);
 
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&p->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 03/15] net: sched: act_gact: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock to protect gact action private state from concurrent
modification during dump and init. Remove rtnl assertion that is no longer
necessary.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_gact.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index 661b72b9147d..bfccd34a3968 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -113,7 +113,7 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 
 	gact = to_gact(*a);
 
-	ASSERT_RTNL();
+	spin_lock(&gact->tcf_lock);
 	gact->tcf_action = parm->action;
 #ifdef CONFIG_GACT_PROB
 	if (p_parm) {
@@ -126,6 +126,8 @@ static int tcf_gact_init(struct net *net, struct nlattr *nla,
 		gact->tcfg_ptype   = p_parm->ptype;
 	}
 #endif
+	spin_unlock(&gact->tcf_lock);
+
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
 	return ret;
@@ -178,10 +180,11 @@ static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 		.index   = gact->tcf_index,
 		.refcnt  = refcount_read(&gact->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&gact->tcf_bindcnt) - bind,
-		.action  = gact->tcf_action,
 	};
 	struct tcf_t t;
 
+	spin_lock(&gact->tcf_lock);
+	opt.action = gact->tcf_action;
 	if (nla_put(skb, TCA_GACT_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 #ifdef CONFIG_GACT_PROB
@@ -199,9 +202,12 @@ static int tcf_gact_dump(struct sk_buff *skb, struct tc_action *a,
 	tcf_tm_dump(&t, &gact->tcf_tm);
 	if (nla_put_64bit(skb, TCA_GACT_TM, sizeof(t), &t, TCA_GACT_PAD))
 		goto nla_put_failure;
+	spin_unlock(&gact->tcf_lock);
+
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&gact->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 04/15] net: sched: act_ife: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock and rcu to protect params pointer from concurrent
modification during dump and init. Use rcu swap operation to reassign
params pointer under protection of tcf lock. (old params value is not used
by init, so there is no need of standalone rcu dereference step)

Ife action has meta-actions that are compiled as standalone modules. Rtnl
mutex must be released while loading a kernel module. In order to support
execution without rtnl mutex, propagate 'rtnl_held' argument to meta action
loading functions. When requesting meta action module, conditionally
release rtnl lock depending on 'rtnl_held' argument.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_ife.c | 40 +++++++++++++++++++++++++---------------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index df4060e32d43..5d200495e467 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -268,7 +268,8 @@ static const char *ife_meta_id2name(u32 metaid)
  * 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)
+				void *val, int len, bool exists,
+				bool rtnl_held)
 {
 	struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 	int ret = 0;
@@ -278,9 +279,11 @@ static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,
 #ifdef CONFIG_MODULES
 		if (exists)
 			spin_unlock_bh(&ife->tcf_lock);
-		rtnl_unlock();
+		if (rtnl_held)
+			rtnl_unlock();
 		request_module("ife-meta-%s", ife_meta_id2name(metaid));
-		rtnl_lock();
+		if (rtnl_held)
+			rtnl_lock();
 		if (exists)
 			spin_lock_bh(&ife->tcf_lock);
 		ops = find_ife_oplist(metaid);
@@ -421,7 +424,7 @@ static void tcf_ife_cleanup(struct tc_action *a)
 
 /* under ife->tcf_lock for existing action */
 static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,
-			     bool exists)
+			     bool exists, bool rtnl_held)
 {
 	int len = 0;
 	int rc = 0;
@@ -433,7 +436,8 @@ 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);
+			rc = load_metaops_and_vet(ife, i, val, len, exists,
+						  rtnl_held);
 			if (rc != 0)
 				return rc;
 
@@ -454,7 +458,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 	struct tc_action_net *tn = net_generic(net, ife_net_id);
 	struct nlattr *tb[TCA_IFE_MAX + 1];
 	struct nlattr *tb2[IFE_META_MAX + 1];
-	struct tcf_ife_params *p, *p_old;
+	struct tcf_ife_params *p;
 	struct tcf_ife_info *ife;
 	u16 ife_type = ETH_P_IFE;
 	struct tc_ife *parm;
@@ -558,7 +562,7 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 			return err;
 		}
 
-		err = populate_metalist(ife, tb2, exists);
+		err = populate_metalist(ife, tb2, exists, rtnl_held);
 		if (err)
 			goto metadata_parse_err;
 
@@ -581,13 +585,13 @@ static int tcf_ife_init(struct net *net, struct nlattr *nla,
 	}
 
 	ife->tcf_action = parm->action;
+	/* protected by tcf_lock when modifying existing action */
+	rcu_swap_protected(ife->params, p, 1);
+
 	if (exists)
 		spin_unlock_bh(&ife->tcf_lock);
-
-	p_old = rtnl_dereference(ife->params);
-	rcu_assign_pointer(ife->params, p);
-	if (p_old)
-		kfree_rcu(p_old, rcu);
+	if (p)
+		kfree_rcu(p, rcu);
 
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
@@ -600,16 +604,20 @@ static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 {
 	unsigned char *b = skb_tail_pointer(skb);
 	struct tcf_ife_info *ife = to_ife(a);
-	struct tcf_ife_params *p = rtnl_dereference(ife->params);
+	struct tcf_ife_params *p;
 	struct tc_ife opt = {
 		.index = ife->tcf_index,
 		.refcnt = refcount_read(&ife->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&ife->tcf_bindcnt) - bind,
-		.action = ife->tcf_action,
-		.flags = p->flags,
 	};
 	struct tcf_t t;
 
+	spin_lock_bh(&ife->tcf_lock);
+	opt.action = ife->tcf_action;
+	p = rcu_dereference_protected(ife->params,
+				      lockdep_is_held(&ife->tcf_lock));
+	opt.flags = p->flags;
+
 	if (nla_put(skb, TCA_IFE_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 
@@ -635,9 +643,11 @@ static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 		pr_info("Failed to dump metalist\n");
 	}
 
+	spin_unlock_bh(&ife->tcf_lock);
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&ife->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 05/15] net: sched: act_ipt: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock to protect ipt action private data from concurrent
modification during dump. Ipt init already takes tcf spinlock when
modifying ipt state.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_ipt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index 0dc787a57798..e149f0e66cb6 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -288,6 +288,7 @@ static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 	 * for foolproof you need to not assume this
 	 */
 
+	spin_lock_bh(&ipt->tcf_lock);
 	t = kmemdup(ipt->tcfi_t, ipt->tcfi_t->u.user.target_size, GFP_ATOMIC);
 	if (unlikely(!t))
 		goto nla_put_failure;
@@ -307,10 +308,12 @@ static int tcf_ipt_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 	if (nla_put_64bit(skb, TCA_IPT_TM, sizeof(tm), &tm, TCA_IPT_PAD))
 		goto nla_put_failure;
 
+	spin_unlock_bh(&ipt->tcf_lock);
 	kfree(t);
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&ipt->tcf_lock);
 	nlmsg_trim(skb, b);
 	kfree(t);
 	return -1;
-- 
2.7.5

[PATCH net-next v2 06/15] net: sched: act_pedit: remove dependency on rtnl lock

[Vlad Buslov]

Rearrange pedit init code to only access pedit action data while holding
tcf spinlock. Change keys allocation type to atomic to allow it to execute
while holding tcf spinlock. Take tcf spinlock in dump function when
accessing pedit action data.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_pedit.c | 40 ++++++++++++++++++++--------------------
 1 file changed, 20 insertions(+), 20 deletions(-)

diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index 43ba999b2d23..3f62da72ab6a 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -187,44 +187,38 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 			tcf_idr_cleanup(tn, parm->index);
 			goto out_free;
 		}
-		p = to_pedit(*a);
-		keys = kmalloc(ksize, GFP_KERNEL);
-		if (!keys) {
-			tcf_idr_release(*a, bind);
-			ret = -ENOMEM;
-			goto out_free;
-		}
 		ret = ACT_P_CREATED;
 	} else if (err > 0) {
 		if (bind)
 			goto out_free;
 		if (!ovr) {
-			tcf_idr_release(*a, bind);
 			ret = -EEXIST;
-			goto out_free;
-		}
-		p = to_pedit(*a);
-		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
-			keys = kmalloc(ksize, GFP_KERNEL);
-			if (!keys) {
-				ret = -ENOMEM;
-				goto out_free;
-			}
+			goto out_release;
 		}
 	} else {
 		return err;
 	}
 
+	p = to_pedit(*a);
 	spin_lock_bh(&p->tcf_lock);
-	p->tcfp_flags = parm->flags;
-	p->tcf_action = parm->action;
-	if (keys) {
+
+	if (ret == ACT_P_CREATED ||
+	    (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
+		keys = kmalloc(ksize, GFP_ATOMIC);
+		if (!keys) {
+			spin_unlock_bh(&p->tcf_lock);
+			ret = -ENOMEM;
+			goto out_release;
+		}
 		kfree(p->tcfp_keys);
 		p->tcfp_keys = keys;
 		p->tcfp_nkeys = parm->nkeys;
 	}
 	memcpy(p->tcfp_keys, parm->keys, ksize);
 
+	p->tcfp_flags = parm->flags;
+	p->tcf_action = parm->action;
+
 	kfree(p->tcfp_keys_ex);
 	p->tcfp_keys_ex = keys_ex;
 
@@ -232,6 +226,9 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla,
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
 	return ret;
+
+out_release:
+	tcf_idr_release(*a, bind);
 out_free:
 	kfree(keys_ex);
 	return ret;
@@ -410,6 +407,7 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 	if (unlikely(!opt))
 		return -ENOBUFS;
 
+	spin_lock_bh(&p->tcf_lock);
 	memcpy(opt->keys, p->tcfp_keys,
 	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
 	opt->index = p->tcf_index;
@@ -432,11 +430,13 @@ static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
 	tcf_tm_dump(&t, &p->tcf_tm);
 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
 		goto nla_put_failure;
+	spin_unlock_bh(&p->tcf_lock);
 
 	kfree(opt);
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&p->tcf_lock);
 	nlmsg_trim(skb, b);
 	kfree(opt);
 	return -1;
-- 
2.7.5

[PATCH net-next v2 07/15] net: sched: act_sample: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock to protect private sample action data from concurrent
modification during dump and init.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_sample.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/net/sched/act_sample.c b/net/sched/act_sample.c
index 2608ccc83e5e..81071afe1b43 100644
--- a/net/sched/act_sample.c
+++ b/net/sched/act_sample.c
@@ -80,11 +80,13 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 	}
 	s = to_sample(*a);
 
+	spin_lock(&s->tcf_lock);
 	s->tcf_action = parm->action;
 	s->rate = nla_get_u32(tb[TCA_SAMPLE_RATE]);
 	s->psample_group_num = nla_get_u32(tb[TCA_SAMPLE_PSAMPLE_GROUP]);
 	psample_group = psample_group_get(net, s->psample_group_num);
 	if (!psample_group) {
+		spin_unlock(&s->tcf_lock);
 		tcf_idr_release(*a, bind);
 		return -ENOMEM;
 	}
@@ -94,6 +96,7 @@ static int tcf_sample_init(struct net *net, struct nlattr *nla,
 		s->truncate = true;
 		s->trunc_size = nla_get_u32(tb[TCA_SAMPLE_TRUNC_SIZE]);
 	}
+	spin_unlock(&s->tcf_lock);
 
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
@@ -105,7 +108,8 @@ static void tcf_sample_cleanup(struct tc_action *a)
 	struct tcf_sample *s = to_sample(a);
 	struct psample_group *psample_group;
 
-	psample_group = rtnl_dereference(s->psample_group);
+	/* last reference to action, no need to lock */
+	psample_group = rcu_dereference_protected(s->psample_group, 1);
 	RCU_INIT_POINTER(s->psample_group, NULL);
 	if (psample_group)
 		psample_group_put(psample_group);
@@ -174,12 +178,13 @@ static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
 	struct tcf_sample *s = to_sample(a);
 	struct tc_sample opt = {
 		.index      = s->tcf_index,
-		.action     = s->tcf_action,
 		.refcnt     = refcount_read(&s->tcf_refcnt) - ref,
 		.bindcnt    = atomic_read(&s->tcf_bindcnt) - bind,
 	};
 	struct tcf_t t;
 
+	spin_lock(&s->tcf_lock);
+	opt.action = s->tcf_action;
 	if (nla_put(skb, TCA_SAMPLE_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 
@@ -196,9 +201,12 @@ static int tcf_sample_dump(struct sk_buff *skb, struct tc_action *a,
 
 	if (nla_put_u32(skb, TCA_SAMPLE_PSAMPLE_GROUP, s->psample_group_num))
 		goto nla_put_failure;
+	spin_unlock(&s->tcf_lock);
+
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&s->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 08/15] net: sched: act_simple: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock to protect private simple action data from concurrent
modification during dump. (simple init already uses tcf spinlock when
changing action state)

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_simple.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index aa51152e0066..18e4452574cd 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -156,10 +156,11 @@ static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 		.index   = d->tcf_index,
 		.refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
-		.action  = d->tcf_action,
 	};
 	struct tcf_t t;
 
+	spin_lock_bh(&d->tcf_lock);
+	opt.action = d->tcf_action;
 	if (nla_put(skb, TCA_DEF_PARMS, sizeof(opt), &opt) ||
 	    nla_put_string(skb, TCA_DEF_DATA, d->tcfd_defdata))
 		goto nla_put_failure;
@@ -167,9 +168,12 @@ static int tcf_simp_dump(struct sk_buff *skb, struct tc_action *a,
 	tcf_tm_dump(&t, &d->tcf_tm);
 	if (nla_put_64bit(skb, TCA_DEF_TM, sizeof(t), &t, TCA_DEF_PAD))
 		goto nla_put_failure;
+	spin_unlock_bh(&d->tcf_lock);
+
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&d->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 09/15] net: sched: act_skbmod: remove dependency on rtnl lock

[Vlad Buslov]

Move read of skbmod_p rcu pointer to be protected by tcf spinlock. Use tcf
spinlock to protect private skbmod data from concurrent modification during
dump.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_skbmod.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index c437c6d51a71..e9c86ade3b40 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -156,7 +156,6 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 
 	d = to_skbmod(*a);
 
-	ASSERT_RTNL();
 	p = kzalloc(sizeof(struct tcf_skbmod_params), GFP_KERNEL);
 	if (unlikely(!p)) {
 		tcf_idr_release(*a, bind);
@@ -166,10 +165,10 @@ static int tcf_skbmod_init(struct net *net, struct nlattr *nla,
 	p->flags = lflags;
 	d->tcf_action = parm->action;
 
-	p_old = rtnl_dereference(d->skbmod_p);
-
 	if (ovr)
 		spin_lock_bh(&d->tcf_lock);
+	/* Protected by tcf_lock if overwriting existing action. */
+	p_old = rcu_dereference_protected(d->skbmod_p, 1);
 
 	if (lflags & SKBMOD_F_DMAC)
 		ether_addr_copy(p->eth_dst, daddr);
@@ -205,15 +204,18 @@ static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
 {
 	struct tcf_skbmod *d = to_skbmod(a);
 	unsigned char *b = skb_tail_pointer(skb);
-	struct tcf_skbmod_params  *p = rtnl_dereference(d->skbmod_p);
+	struct tcf_skbmod_params  *p;
 	struct tc_skbmod opt = {
 		.index   = d->tcf_index,
 		.refcnt  = refcount_read(&d->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&d->tcf_bindcnt) - bind,
-		.action  = d->tcf_action,
 	};
 	struct tcf_t t;
 
+	spin_lock_bh(&d->tcf_lock);
+	opt.action = d->tcf_action;
+	p = rcu_dereference_protected(d->skbmod_p,
+				      lockdep_is_held(&d->tcf_lock));
 	opt.flags  = p->flags;
 	if (nla_put(skb, TCA_SKBMOD_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
@@ -231,8 +233,10 @@ static int tcf_skbmod_dump(struct sk_buff *skb, struct tc_action *a,
 	if (nla_put_64bit(skb, TCA_SKBMOD_TM, sizeof(t), &t, TCA_SKBMOD_PAD))
 		goto nla_put_failure;
 
+	spin_unlock_bh(&d->tcf_lock);
 	return skb->len;
 nla_put_failure:
+	spin_unlock_bh(&d->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 10/15] net: sched: act_tunnel_key: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf lock to protect tunnel key action struct private data from
concurrent modification in init and dump. Use rcu swap operation to
reassign params pointer under protection of tcf lock. (old params value is
not used by init, so there is no need of standalone rcu dereference step)

Remove rtnl lock assertion that is no longer required.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_tunnel_key.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index d42d9e112789..ba2ae9f75ef5 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -204,7 +204,6 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 {
 	struct tc_action_net *tn = net_generic(net, tunnel_key_net_id);
 	struct nlattr *tb[TCA_TUNNEL_KEY_MAX + 1];
-	struct tcf_tunnel_key_params *params_old;
 	struct tcf_tunnel_key_params *params_new;
 	struct metadata_dst *metadata = NULL;
 	struct tc_tunnel_key *parm;
@@ -346,24 +345,22 @@ static int tunnel_key_init(struct net *net, struct nlattr *nla,
 
 	t = to_tunnel_key(*a);
 
-	ASSERT_RTNL();
 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
 	if (unlikely(!params_new)) {
 		tcf_idr_release(*a, bind);
 		NL_SET_ERR_MSG(extack, "Cannot allocate tunnel key parameters");
 		return -ENOMEM;
 	}
-
-	params_old = rtnl_dereference(t->params);
-
-	t->tcf_action = parm->action;
 	params_new->tcft_action = parm->t_action;
 	params_new->tcft_enc_metadata = metadata;
 
-	rcu_assign_pointer(t->params, params_new);
-
-	if (params_old)
-		kfree_rcu(params_old, rcu);
+	spin_lock(&t->tcf_lock);
+	t->tcf_action = parm->action;
+	rcu_swap_protected(t->params, params_new,
+			   lockdep_is_held(&t->tcf_lock));
+	spin_unlock(&t->tcf_lock);
+	if (params_new)
+		kfree_rcu(params_new, rcu);
 
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
@@ -485,12 +482,13 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a,
 		.index    = t->tcf_index,
 		.refcnt   = refcount_read(&t->tcf_refcnt) - ref,
 		.bindcnt  = atomic_read(&t->tcf_bindcnt) - bind,
-		.action   = t->tcf_action,
 	};
 	struct tcf_t tm;
 
-	params = rtnl_dereference(t->params);
-
+	spin_lock(&t->tcf_lock);
+	params = rcu_dereference_protected(t->params,
+					   lockdep_is_held(&t->tcf_lock));
+	opt.action   = t->tcf_action;
 	opt.t_action = params->tcft_action;
 
 	if (nla_put(skb, TCA_TUNNEL_KEY_PARMS, sizeof(opt), &opt))
@@ -522,10 +520,12 @@ static int tunnel_key_dump(struct sk_buff *skb, struct tc_action *a,
 	if (nla_put_64bit(skb, TCA_TUNNEL_KEY_TM, sizeof(tm),
 			  &tm, TCA_TUNNEL_KEY_PAD))
 		goto nla_put_failure;
+	spin_unlock(&t->tcf_lock);
 
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&t->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 11/15] net: sched: act_vlan: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock to protect vlan action private data from concurrent
modification during dump and init. Use rcu swap operation to reassign
params pointer under protection of tcf lock. (old params value is not used
by init, so there is no need of standalone rcu dereference step)

Remove rtnl assertion that is no longer necessary.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_vlan.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index 15a0ee214c9c..5bde17fe3608 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -109,7 +109,7 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 {
 	struct tc_action_net *tn = net_generic(net, vlan_net_id);
 	struct nlattr *tb[TCA_VLAN_MAX + 1];
-	struct tcf_vlan_params *p, *p_old;
+	struct tcf_vlan_params *p;
 	struct tc_vlan *parm;
 	struct tcf_vlan *v;
 	int action;
@@ -202,26 +202,24 @@ static int tcf_vlan_init(struct net *net, struct nlattr *nla,
 
 	v = to_vlan(*a);
 
-	ASSERT_RTNL();
 	p = kzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p) {
 		tcf_idr_release(*a, bind);
 		return -ENOMEM;
 	}
 
-	v->tcf_action = parm->action;
-
-	p_old = rtnl_dereference(v->vlan_p);
-
 	p->tcfv_action = action;
 	p->tcfv_push_vid = push_vid;
 	p->tcfv_push_prio = push_prio;
 	p->tcfv_push_proto = push_proto;
 
-	rcu_assign_pointer(v->vlan_p, p);
+	spin_lock(&v->tcf_lock);
+	v->tcf_action = parm->action;
+	rcu_swap_protected(v->vlan_p, p, lockdep_is_held(&v->tcf_lock));
+	spin_unlock(&v->tcf_lock);
 
-	if (p_old)
-		kfree_rcu(p_old, rcu);
+	if (p)
+		kfree_rcu(p, rcu);
 
 	if (ret == ACT_P_CREATED)
 		tcf_idr_insert(tn, *a);
@@ -243,16 +241,18 @@ static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
 {
 	unsigned char *b = skb_tail_pointer(skb);
 	struct tcf_vlan *v = to_vlan(a);
-	struct tcf_vlan_params *p = rtnl_dereference(v->vlan_p);
+	struct tcf_vlan_params *p;
 	struct tc_vlan opt = {
 		.index    = v->tcf_index,
 		.refcnt   = refcount_read(&v->tcf_refcnt) - ref,
 		.bindcnt  = atomic_read(&v->tcf_bindcnt) - bind,
-		.action   = v->tcf_action,
-		.v_action = p->tcfv_action,
 	};
 	struct tcf_t t;
 
+	spin_lock(&v->tcf_lock);
+	opt.action = v->tcf_action;
+	p = rcu_dereference_protected(v->vlan_p, lockdep_is_held(&v->tcf_lock));
+	opt.v_action = p->tcfv_action;
 	if (nla_put(skb, TCA_VLAN_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 
@@ -268,9 +268,12 @@ static int tcf_vlan_dump(struct sk_buff *skb, struct tc_action *a,
 	tcf_tm_dump(&t, &v->tcf_tm);
 	if (nla_put_64bit(skb, TCA_VLAN_TM, sizeof(t), &t, TCA_VLAN_PAD))
 		goto nla_put_failure;
+	spin_unlock(&v->tcf_lock);
+
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&v->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

[PATCH net-next v2 12/15] net: sched: extend action ops with put_dev callback

[Vlad Buslov]

As a preparation for removing dependency on rtnl lock from rules update
path, all users of shared objects must take reference while working with
them.

Extend action ops with put_dev() API to be used on net device returned by
get_dev().

Modify mirred action (only action that implements get_dev callback):
- Take reference to net device in get_dev.
- Implement put_dev API that releases reference to net device.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 include/net/act_api.h  |  1 +
 net/sched/act_mirred.c | 12 +++++++++++-
 net/sched/cls_api.c    |  1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 8c9bc02d05e1..1ad5b19e83a9 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -101,6 +101,7 @@ struct tc_action_ops {
 	void	(*stats_update)(struct tc_action *, u64, u32, u64);
 	size_t  (*get_fill_size)(const struct tc_action *act);
 	struct net_device *(*get_dev)(const struct tc_action *a);
+	void	(*put_dev)(struct net_device *dev);
 	int     (*delete)(struct net *net, u32 index);
 };
 
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index b26d060da08e..7a045cc7fe3b 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -358,8 +358,17 @@ static struct notifier_block mirred_device_notifier = {
 static struct net_device *tcf_mirred_get_dev(const struct tc_action *a)
 {
 	struct tcf_mirred *m = to_mirred(a);
+	struct net_device *dev = rtnl_dereference(m->tcfm_dev);
+
+	if (dev)
+		dev_hold(dev);
 
-	return rtnl_dereference(m->tcfm_dev);
+	return dev;
+}
+
+static void tcf_mirred_put_dev(struct net_device *dev)
+{
+	dev_put(dev);
 }
 
 static int tcf_mirred_delete(struct net *net, u32 index)
@@ -382,6 +391,7 @@ static struct tc_action_ops act_mirred_ops = {
 	.lookup		=	tcf_mirred_search,
 	.size		=	sizeof(struct tcf_mirred),
 	.get_dev	=	tcf_mirred_get_dev,
+	.put_dev	=	tcf_mirred_put_dev,
 	.delete		=	tcf_mirred_delete,
 };
 
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
index e8b0bbd0883f..bdabf8144e21 100644
--- a/net/sched/cls_api.c
+++ b/net/sched/cls_api.c
@@ -2167,6 +2167,7 @@ static int tc_exts_setup_cb_egdev_call(struct tcf_exts *exts,
 		if (!dev)
 			continue;
 		ret = tc_setup_cb_egdev_call(dev, type, type_data, err_stop);
+		a->ops->put_dev(dev);
 		if (ret < 0)
 			return ret;
 		ok_count += ret;
-- 
2.7.5

[PATCH net-next v2 13/15] net: sched: act_mirred: remove dependency on rtnl lock

[Vlad Buslov]

Re-introduce mirred list spinlock, that was removed some time ago, in order
to protect it from concurrent modifications, instead of relying on rtnl
lock.

Use tcf spinlock to protect mirred action private data from concurrent
modification in init and dump. Rearrange access to mirred data in order to
be performed only while holding the lock.

Rearrange net dev access to always hold reference while working with it,
instead of relying on rntl lock.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_mirred.c | 78 +++++++++++++++++++++++++++++++++-----------------
 1 file changed, 51 insertions(+), 27 deletions(-)

diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 7a045cc7fe3b..327be257033d 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -30,6 +30,7 @@
 #include <net/tc_act/tc_mirred.h>
 
 static LIST_HEAD(mirred_list);
+static DEFINE_SPINLOCK(mirred_list_lock);
 
 static bool tcf_mirred_is_act_redirect(int action)
 {
@@ -62,13 +63,23 @@ static bool tcf_mirred_can_reinsert(int action)
 	return false;
 }
 
+static struct net_device *tcf_mirred_dev_dereference(struct tcf_mirred *m)
+{
+	return rcu_dereference_protected(m->tcfm_dev,
+					 lockdep_is_held(&m->tcf_lock));
+}
+
 static void tcf_mirred_release(struct tc_action *a)
 {
 	struct tcf_mirred *m = to_mirred(a);
 	struct net_device *dev;
 
+	spin_lock(&mirred_list_lock);
 	list_del(&m->tcfm_list);
-	dev = rtnl_dereference(m->tcfm_dev);
+	spin_unlock(&mirred_list_lock);
+
+	/* last reference to action, no need to lock */
+	dev = rcu_dereference_protected(m->tcfm_dev, 1);
 	if (dev)
 		dev_put(dev);
 }
@@ -128,22 +139,9 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 		NL_SET_ERR_MSG_MOD(extack, "Unknown mirred option");
 		return -EINVAL;
 	}
-	if (parm->ifindex) {
-		dev = __dev_get_by_index(net, parm->ifindex);
-		if (dev == NULL) {
-			if (exists)
-				tcf_idr_release(*a, bind);
-			else
-				tcf_idr_cleanup(tn, parm->index);
-			return -ENODEV;
-		}
-		mac_header_xmit = dev_is_mac_header_xmit(dev);
-	} else {
-		dev = NULL;
-	}
 
 	if (!exists) {
-		if (!dev) {
+		if (!parm->ifindex) {
 			tcf_idr_cleanup(tn, parm->index);
 			NL_SET_ERR_MSG_MOD(extack, "Specified device does not exist");
 			return -EINVAL;
@@ -161,19 +159,31 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	}
 	m = to_mirred(*a);
 
-	ASSERT_RTNL();
+	spin_lock(&m->tcf_lock);
 	m->tcf_action = parm->action;
 	m->tcfm_eaction = parm->eaction;
-	if (dev != NULL) {
-		if (ret != ACT_P_CREATED)
-			dev_put(rcu_dereference_protected(m->tcfm_dev, 1));
-		dev_hold(dev);
-		rcu_assign_pointer(m->tcfm_dev, dev);
+
+	if (parm->ifindex) {
+		dev = dev_get_by_index(net, parm->ifindex);
+		if (!dev) {
+			spin_unlock(&m->tcf_lock);
+			tcf_idr_release(*a, bind);
+			return -ENODEV;
+		}
+		mac_header_xmit = dev_is_mac_header_xmit(dev);
+		rcu_swap_protected(m->tcfm_dev, dev,
+				   lockdep_is_held(&m->tcf_lock));
+		if (dev)
+			dev_put(dev);
 		m->tcfm_mac_header_xmit = mac_header_xmit;
 	}
+	spin_unlock(&m->tcf_lock);
 
 	if (ret == ACT_P_CREATED) {
+		spin_lock(&mirred_list_lock);
 		list_add(&m->tcfm_list, &mirred_list);
+		spin_unlock(&mirred_list_lock);
+
 		tcf_idr_insert(tn, *a);
 	}
 
@@ -287,26 +297,33 @@ static int tcf_mirred_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 {
 	unsigned char *b = skb_tail_pointer(skb);
 	struct tcf_mirred *m = to_mirred(a);
-	struct net_device *dev = rtnl_dereference(m->tcfm_dev);
 	struct tc_mirred opt = {
 		.index   = m->tcf_index,
-		.action  = m->tcf_action,
 		.refcnt  = refcount_read(&m->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&m->tcf_bindcnt) - bind,
-		.eaction = m->tcfm_eaction,
-		.ifindex = dev ? dev->ifindex : 0,
 	};
+	struct net_device *dev;
 	struct tcf_t t;
 
+	spin_lock(&m->tcf_lock);
+	opt.action = m->tcf_action;
+	opt.eaction = m->tcfm_eaction;
+	dev = tcf_mirred_dev_dereference(m);
+	if (dev)
+		opt.ifindex = dev->ifindex;
+
 	if (nla_put(skb, TCA_MIRRED_PARMS, sizeof(opt), &opt))
 		goto nla_put_failure;
 
 	tcf_tm_dump(&t, &m->tcf_tm);
 	if (nla_put_64bit(skb, TCA_MIRRED_TM, sizeof(t), &t, TCA_MIRRED_PAD))
 		goto nla_put_failure;
+	spin_unlock(&m->tcf_lock);
+
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock(&m->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
@@ -337,15 +354,19 @@ static int mirred_device_event(struct notifier_block *unused,
 
 	ASSERT_RTNL();
 	if (event == NETDEV_UNREGISTER) {
+		spin_lock(&mirred_list_lock);
 		list_for_each_entry(m, &mirred_list, tcfm_list) {
-			if (rcu_access_pointer(m->tcfm_dev) == dev) {
+			spin_lock(&m->tcf_lock);
+			if (tcf_mirred_dev_dereference(m) == dev) {
 				dev_put(dev);
 				/* Note : no rcu grace period necessary, as
 				 * net_device are already rcu protected.
 				 */
 				RCU_INIT_POINTER(m->tcfm_dev, NULL);
 			}
+			spin_unlock(&m->tcf_lock);
 		}
+		spin_unlock(&mirred_list_lock);
 	}
 
 	return NOTIFY_DONE;
@@ -358,10 +379,13 @@ static struct notifier_block mirred_device_notifier = {
 static struct net_device *tcf_mirred_get_dev(const struct tc_action *a)
 {
 	struct tcf_mirred *m = to_mirred(a);
-	struct net_device *dev = rtnl_dereference(m->tcfm_dev);
+	struct net_device *dev;
 
+	rcu_read_lock();
+	dev = rcu_dereference(m->tcfm_dev);
 	if (dev)
 		dev_hold(dev);
+	rcu_read_unlock();
 
 	return dev;
 }
-- 
2.7.5

[PATCH net-next v2 14/15] net: core: protect rate estimator statistics pointer with lock

[Vlad Buslov]

Extend gen_new_estimator() to also take stats_lock when re-assigning rate
estimator statistics pointer. (to be used by unlocked actions)

Rename 'stats_lock' to 'lock' and change argument description to explain
that it is now also used for control path.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 include/net/gen_stats.h  |  4 ++--
 net/core/gen_estimator.c | 21 +++++++++++++--------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/net/gen_stats.h b/include/net/gen_stats.h
index 0304ba2ae353..883bb9085f15 100644
--- a/include/net/gen_stats.h
+++ b/include/net/gen_stats.h
@@ -59,13 +59,13 @@ int gnet_stats_finish_copy(struct gnet_dump *d);
 int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
-		      spinlock_t *stats_lock,
+		      spinlock_t *lock,
 		      seqcount_t *running, struct nlattr *opt);
 void gen_kill_estimator(struct net_rate_estimator __rcu **ptr);
 int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **ptr,
-			  spinlock_t *stats_lock,
+			  spinlock_t *lock,
 			  seqcount_t *running, struct nlattr *opt);
 bool gen_estimator_active(struct net_rate_estimator __rcu **ptr);
 bool gen_estimator_read(struct net_rate_estimator __rcu **ptr,
diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c
index 98fd12721221..e4e442d70c2d 100644
--- a/net/core/gen_estimator.c
+++ b/net/core/gen_estimator.c
@@ -112,7 +112,7 @@ static void est_timer(struct timer_list *t)
  * @bstats: basic statistics
  * @cpu_bstats: bstats per cpu
  * @rate_est: rate estimator statistics
- * @stats_lock: statistics lock
+ * @lock: lock for statistics and control path
  * @running: qdisc running seqcount
  * @opt: rate estimator configuration TLV
  *
@@ -128,7 +128,7 @@ static void est_timer(struct timer_list *t)
 int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 		      struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 		      struct net_rate_estimator __rcu **rate_est,
-		      spinlock_t *stats_lock,
+		      spinlock_t *lock,
 		      seqcount_t *running,
 		      struct nlattr *opt)
 {
@@ -154,19 +154,22 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 	seqcount_init(&est->seq);
 	intvl_log = parm->interval + 2;
 	est->bstats = bstats;
-	est->stats_lock = stats_lock;
+	est->stats_lock = lock;
 	est->running  = running;
 	est->ewma_log = parm->ewma_log;
 	est->intvl_log = intvl_log;
 	est->cpu_bstats = cpu_bstats;
 
-	if (stats_lock)
+	if (lock)
 		local_bh_disable();
 	est_fetch_counters(est, &b);
-	if (stats_lock)
+	if (lock)
 		local_bh_enable();
 	est->last_bytes = b.bytes;
 	est->last_packets = b.packets;
+
+	if (lock)
+		spin_lock_bh(lock);
 	old = rcu_dereference_protected(*rate_est, 1);
 	if (old) {
 		del_timer_sync(&old->timer);
@@ -179,6 +182,8 @@ int gen_new_estimator(struct gnet_stats_basic_packed *bstats,
 	mod_timer(&est->timer, est->next_jiffies);
 
 	rcu_assign_pointer(*rate_est, est);
+	if (lock)
+		spin_unlock_bh(lock);
 	if (old)
 		kfree_rcu(old, rcu);
 	return 0;
@@ -209,7 +214,7 @@ EXPORT_SYMBOL(gen_kill_estimator);
  * @bstats: basic statistics
  * @cpu_bstats: bstats per cpu
  * @rate_est: rate estimator statistics
- * @stats_lock: statistics lock
+ * @lock: lock for statistics and control path
  * @running: qdisc running seqcount (might be NULL)
  * @opt: rate estimator configuration TLV
  *
@@ -221,11 +226,11 @@ EXPORT_SYMBOL(gen_kill_estimator);
 int gen_replace_estimator(struct gnet_stats_basic_packed *bstats,
 			  struct gnet_stats_basic_cpu __percpu *cpu_bstats,
 			  struct net_rate_estimator __rcu **rate_est,
-			  spinlock_t *stats_lock,
+			  spinlock_t *lock,
 			  seqcount_t *running, struct nlattr *opt)
 {
 	return gen_new_estimator(bstats, cpu_bstats, rate_est,
-				 stats_lock, running, opt);
+				 lock, running, opt);
 }
 EXPORT_SYMBOL(gen_replace_estimator);
 
-- 
2.7.5

[PATCH net-next v2 15/15] net: sched: act_police: remove dependency on rtnl lock

[Vlad Buslov]

Use tcf spinlock to protect police action private data from concurrent
modification during dump. (init already uses tcf spinlock when changing
police action state)

Pass tcf spinlock as estimator lock argument to gen_replace_estimator()
during action init.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
---
 net/sched/act_police.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index 1f3192ea8df7..88c16d80c1cf 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -274,14 +274,15 @@ static int tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a,
 	struct tcf_police *police = to_police(a);
 	struct tc_police opt = {
 		.index = police->tcf_index,
-		.action = police->tcf_action,
-		.mtu = police->tcfp_mtu,
-		.burst = PSCHED_NS2TICKS(police->tcfp_burst),
 		.refcnt = refcount_read(&police->tcf_refcnt) - ref,
 		.bindcnt = atomic_read(&police->tcf_bindcnt) - bind,
 	};
 	struct tcf_t t;
 
+	spin_lock_bh(&police->tcf_lock);
+	opt.action = police->tcf_action;
+	opt.mtu = police->tcfp_mtu;
+	opt.burst = PSCHED_NS2TICKS(police->tcfp_burst);
 	if (police->rate_present)
 		psched_ratecfg_getrate(&opt.rate, &police->rate);
 	if (police->peak_present)
@@ -301,10 +302,12 @@ static int tcf_act_police_dump(struct sk_buff *skb, struct tc_action *a,
 	t.expires = jiffies_to_clock_t(police->tcf_tm.expires);
 	if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
 		goto nla_put_failure;
+	spin_unlock_bh(&police->tcf_lock);
 
 	return skb->len;
 
 nla_put_failure:
+	spin_unlock_bh(&police->tcf_lock);
 	nlmsg_trim(skb, b);
 	return -1;
 }
-- 
2.7.5

Re: [PATCH net-next v2 00/15] Remove rtnl lock dependency from all action implementations

[David Miller]

From: Vlad Buslov <vladbu@mellanox.com>
Date: Fri, 10 Aug 2018 20:51:40 +0300

> The goal of this change is to update specific actions APIs that access
> action private state directly, in order to be independent from external
> locking. General approach is to re-use existing tcf_lock spinlock (used
> by some action implementation to synchronize control path with data
> path) to protect action private state from concurrent modification. If
> action has rcu-protected pointer, tcf spinlock is used to protect its
> update code, instead of relying on rtnl lock.
> 
> Some actions need to determine rtnl mutex status in order to release it.
> For example, ife action can load additional kernel modules(meta ops) and
> must make sure that no locks are held during module load. In such cases
> 'rtnl_held' argument is used to conditionally release rtnl mutex.
 ...

I like these changes, nice work.  If there are any bugs or whatever, we
can fix them on top.

Series applied to net-next, thanks.