Message-ID: <DM5PR1301MB21728E3DA88CC9B1364F91DEE79F9@DM5PR1301MB2172.namprd13.prod.outlook.com>
Date:   Mon, 22 Nov 2021 10:13:00 +0000
From:   Baowen Zheng <baowen.zheng@...igine.com>
To:     Vlad Buslov <vladbu@...dia.com>,
        Simon Horman <simon.horman@...igine.com>
CC:     "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        Cong Wang <xiyou.wangcong@...il.com>,
        Ido Schimmel <idosch@...dia.com>,
        Jamal Hadi Salim <jhs@...atatu.com>,
        Jiri Pirko <jiri@...nulli.us>, Oz Shlomo <ozsh@...dia.com>,
        Roi Dayan <roid@...dia.com>,
        Louis Peens <louis.peens@...igine.com>,
        oss-drivers <oss-drivers@...igine.com>
Subject: RE: [PATCH v4 08/10] flow_offload: add reoffload process to update
 hw_count

On November 20, 2021 4:09 AM, Vlad Buslov wrote:
>On Thu 18 Nov 2021 at 15:08, Simon Horman <simon.horman@...igine.com>
>wrote:
>> From: Baowen Zheng <baowen.zheng@...igine.com>
>>
>> Add reoffload process to update hw_count when driver is inserted or
>> removed.
>>
>> When reoffloading actions, we still offload the actions that are added
>> independent of filters.
>>
>> Signed-off-by: Baowen Zheng <baowen.zheng@...igine.com>
>> Signed-off-by: Louis Peens <louis.peens@...igine.com>
>> Signed-off-by: Simon Horman <simon.horman@...igine.com>
>> ---
>>  include/net/act_api.h   |  24 +++++
>>  net/core/flow_offload.c |   4 +
>>  net/sched/act_api.c     | 213
>++++++++++++++++++++++++++++++++++++----
>>  3 files changed, 222 insertions(+), 19 deletions(-)
>>
>> diff --git a/include/net/act_api.h b/include/net/act_api.h index
>> 7900598d2dd3..e5e6e58df618 100644
>> --- a/include/net/act_api.h
>> +++ b/include/net/act_api.h
>> @@ -7,6 +7,7 @@
>>  */
>>
>>  #include <linux/refcount.h>
>> +#include <net/flow_offload.h>
>>  #include <net/sch_generic.h>
>>  #include <net/pkt_sched.h>
>>  #include <net/net_namespace.h>
>> @@ -243,11 +244,26 @@ static inline void flow_action_hw_count_set(struct
>tc_action *act,
>>  	act->in_hw_count = hw_count;
>>  }
>>
>> +static inline void flow_action_hw_count_inc(struct tc_action *act,
>> +					    u32 hw_count)
>> +{
>> +	act->in_hw_count += hw_count;
>> +}
>> +
>> +static inline void flow_action_hw_count_dec(struct tc_action *act,
>> +					    u32 hw_count)
>> +{
>> +	act->in_hw_count = act->in_hw_count > hw_count ?
>> +			   act->in_hw_count - hw_count : 0; }
>> +
>>  void tcf_action_update_stats(struct tc_action *a, u64 bytes, u64 packets,
>>  			     u64 drops, bool hw);
>>  int tcf_action_copy_stats(struct sk_buff *, struct tc_action *, int);
>>
>>  int tcf_action_update_hw_stats(struct tc_action *action);
>> +int tcf_action_reoffload_cb(flow_indr_block_bind_cb_t *cb,
>> +			    void *cb_priv, bool add);
>>  int tcf_action_check_ctrlact(int action, struct tcf_proto *tp,
>>  			     struct tcf_chain **handle,
>>  			     struct netlink_ext_ack *newchain); @@ -259,6
>+275,14 @@
>> DECLARE_STATIC_KEY_FALSE(tcf_frag_xmit_count);
>>  #endif
>>
>>  int tcf_dev_queue_xmit(struct sk_buff *skb, int (*xmit)(struct
>> sk_buff *skb));
>> +
>> +#else /* !CONFIG_NET_CLS_ACT */
>> +
>> +static inline int tcf_action_reoffload_cb(flow_indr_block_bind_cb_t *cb,
>> +					  void *cb_priv, bool add) {
>> +	return 0;
>> +}
>> +
>>  #endif /* CONFIG_NET_CLS_ACT */
>>
>>  static inline void tcf_action_stats_update(struct tc_action *a, u64
>> bytes, diff --git a/net/core/flow_offload.c b/net/core/flow_offload.c
>> index 6676431733ef..92000164ac37 100644
>> --- a/net/core/flow_offload.c
>> +++ b/net/core/flow_offload.c
>> @@ -1,6 +1,7 @@
>>  /* SPDX-License-Identifier: GPL-2.0 */  #include <linux/kernel.h>
>> #include <linux/slab.h>
>> +#include <net/act_api.h>
>>  #include <net/flow_offload.h>
>>  #include <linux/rtnetlink.h>
>>  #include <linux/mutex.h>
>> @@ -418,6 +419,8 @@ int
>flow_indr_dev_register(flow_indr_block_bind_cb_t *cb, void *cb_priv)
>>  	existing_qdiscs_register(cb, cb_priv);
>>  	mutex_unlock(&flow_indr_block_lock);
>>
>> +	tcf_action_reoffload_cb(cb, cb_priv, true);
>> +
>>  	return 0;
>>  }
>>  EXPORT_SYMBOL(flow_indr_dev_register);
>> @@ -470,6 +473,7 @@ void
>flow_indr_dev_unregister(flow_indr_block_bind_cb_t *cb, void *cb_priv,
>>  	__flow_block_indr_cleanup(release, cb_priv, &cleanup_list);
>>  	mutex_unlock(&flow_indr_block_lock);
>>
>> +	tcf_action_reoffload_cb(cb, cb_priv, false);
>>  	flow_block_indr_notify(&cleanup_list);
>>  	kfree(indr_dev);
>>  }
>> diff --git a/net/sched/act_api.c b/net/sched/act_api.c index
>> f5834d47a392..ada51b2df851 100644
>> --- a/net/sched/act_api.c
>> +++ b/net/sched/act_api.c
>> @@ -225,15 +225,11 @@ static int flow_action_init(struct
>flow_offload_action *fl_action,
>>  	return 0;
>>  }
>>
>> -static int tcf_action_offload_cmd(struct flow_offload_action *fl_act,
>> -				  u32 *hw_count,
>> -				  struct netlink_ext_ack *extack)
>> +static int tcf_action_offload_cmd_ex(struct flow_offload_action *fl_act,
>> +				     u32 *hw_count)
>>  {
>>  	int err;
>>
>> -	if (IS_ERR(fl_act))
>> -		return PTR_ERR(fl_act);
>> -
>>  	err = flow_indr_dev_setup_offload(NULL, NULL, TC_SETUP_ACT,
>>  					  fl_act, NULL, NULL);
>>  	if (err < 0)
>> @@ -245,9 +241,41 @@ static int tcf_action_offload_cmd(struct
>flow_offload_action *fl_act,
>>  	return 0;
>>  }
>>
>> +static int tcf_action_offload_cmd_cb_ex(struct flow_offload_action
>*fl_act,
>> +					u32 *hw_count,
>> +					flow_indr_block_bind_cb_t *cb,
>> +					void *cb_priv)
>> +{
>> +	int err;
>> +
>> +	err = cb(NULL, NULL, cb_priv, TC_SETUP_ACT, NULL, fl_act, NULL);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	if (hw_count)
>> +		*hw_count = 1;
>> +
>> +	return 0;
>> +}
>> +
>> +static int tcf_action_offload_cmd(struct flow_offload_action *fl_act,
>> +				  u32 *hw_count,
>> +				  flow_indr_block_bind_cb_t *cb,
>> +				  void *cb_priv)
>> +{
>> +	if (IS_ERR(fl_act))
>> +		return PTR_ERR(fl_act);
>> +
>> +	return cb ? tcf_action_offload_cmd_cb_ex(fl_act, hw_count,
>> +						 cb, cb_priv) :
>> +		    tcf_action_offload_cmd_ex(fl_act, hw_count); }
>> +
>>  /* offload the tc command after inserted */ -static int
>> tcf_action_offload_add(struct tc_action *action,
>> -				  struct netlink_ext_ack *extack)
>> +static int tcf_action_offload_add_ex(struct tc_action *action,
>> +				     struct netlink_ext_ack *extack,
>> +				     flow_indr_block_bind_cb_t *cb,
>> +				     void *cb_priv)
>>  {
>>  	bool skip_sw = tc_act_skip_sw(action->tcfa_flags);
>>  	struct tc_action *actions[TCA_ACT_MAX_PRIO] = { @@ -275,9 +303,10
>@@
>> static int tcf_action_offload_add(struct tc_action *action,
>>  		goto fl_err;
>>  	}
>>
>> -	err = tcf_action_offload_cmd(fl_action, &in_hw_count, extack);
>> +	err = tcf_action_offload_cmd(fl_action, &in_hw_count, cb, cb_priv);
>>  	if (!err)
>> -		flow_action_hw_count_set(action, in_hw_count);
>> +		cb ? flow_action_hw_count_inc(action, in_hw_count) :
>> +		     flow_action_hw_count_set(action, in_hw_count);
>>
>>  	if (skip_sw && !tc_act_in_hw(action))
>>  		err = -EINVAL;
>> @@ -290,6 +319,12 @@ static int tcf_action_offload_add(struct tc_action
>*action,
>>  	return err;
>>  }
>>
>> +static int tcf_action_offload_add(struct tc_action *action,
>> +				  struct netlink_ext_ack *extack) {
>> +	return tcf_action_offload_add_ex(action, extack, NULL, NULL); }
>> +
>>  int tcf_action_update_hw_stats(struct tc_action *action)  {
>>  	struct flow_offload_action fl_act = {}; @@ -302,7 +337,7 @@ int
>> tcf_action_update_hw_stats(struct tc_action *action)
>>  	if (err)
>>  		return err;
>>
>> -	err = tcf_action_offload_cmd(&fl_act, NULL, NULL);
>> +	err = tcf_action_offload_cmd(&fl_act, NULL, NULL, NULL);
>>  	if (!err) {
>>  		preempt_disable();
>>  		tcf_action_stats_update(action, fl_act.stats.bytes, @@ -321,7
>> +356,9 @@ int tcf_action_update_hw_stats(struct tc_action *action)  }
>> EXPORT_SYMBOL(tcf_action_update_hw_stats);
>>
>> -static int tcf_action_offload_del(struct tc_action *action)
>> +static int tcf_action_offload_del_ex(struct tc_action *action,
>> +				     flow_indr_block_bind_cb_t *cb,
>> +				     void *cb_priv)
>>  {
>>  	struct flow_offload_action fl_act;
>>  	u32 in_hw_count = 0;
>> @@ -337,16 +374,25 @@ static int tcf_action_offload_del(struct tc_action
>*action)
>>  	if (err)
>>  		return err;
>>
>> -	err = tcf_action_offload_cmd(&fl_act, &in_hw_count, NULL);
>> -	if (err)
>> +	err = tcf_action_offload_cmd(&fl_act, &in_hw_count, cb, cb_priv);
>> +	if (err < 0)
>>  		return err;
>>
>> -	if (action->in_hw_count != in_hw_count)
>> +	if (!cb && action->in_hw_count != in_hw_count)
>>  		return -EINVAL;
>>
>> +	/* do not need to update hw state when deleting action */
>> +	if (cb && in_hw_count)
>> +		flow_action_hw_count_dec(action, in_hw_count);
>> +
>>  	return 0;
>>  }
>>
>> +static int tcf_action_offload_del(struct tc_action *action) {
>> +	return tcf_action_offload_del_ex(action, NULL, NULL); }
>> +
>>  static void tcf_action_cleanup(struct tc_action *p)  {
>>  	tcf_action_offload_del(p);
>> @@ -841,6 +887,59 @@ EXPORT_SYMBOL(tcf_idrinfo_destroy);
>>
>>  static LIST_HEAD(act_base);
>>  static DEFINE_RWLOCK(act_mod_lock);
>> +/* since act ops id is stored in pernet subsystem list,
>> + * then there is no way to walk through only all the action
>> + * subsystem, so we keep tc action pernet ops id for
>> + * reoffload to walk through.
>> + */
>> +static LIST_HEAD(act_pernet_id_list); static
>> +DEFINE_MUTEX(act_id_mutex); struct tc_act_pernet_id {
>> +	struct list_head list;
>> +	unsigned int id;
>> +};
>> +
>> +static int tcf_pernet_add_id_list(unsigned int id) {
>> +	struct tc_act_pernet_id *id_ptr;
>> +	int ret = 0;
>> +
>> +	mutex_lock(&act_id_mutex);
>> +	list_for_each_entry(id_ptr, &act_pernet_id_list, list) {
>> +		if (id_ptr->id == id) {
>> +			ret = -EEXIST;
>> +			goto err_out;
>> +		}
>> +	}
>> +
>> +	id_ptr = kzalloc(sizeof(*id_ptr), GFP_KERNEL);
>> +	if (!id_ptr) {
>> +		ret = -ENOMEM;
>> +		goto err_out;
>> +	}
>> +	id_ptr->id = id;
>> +
>> +	list_add_tail(&id_ptr->list, &act_pernet_id_list);
>> +
>> +err_out:
>> +	mutex_unlock(&act_id_mutex);
>> +	return ret;
>> +}
>> +
>> +static void tcf_pernet_del_id_list(unsigned int id) {
>> +	struct tc_act_pernet_id *id_ptr;
>> +
>> +	mutex_lock(&act_id_mutex);
>> +	list_for_each_entry(id_ptr, &act_pernet_id_list, list) {
>> +		if (id_ptr->id == id) {
>> +			list_del(&id_ptr->list);
>> +			kfree(id_ptr);
>> +			break;
>> +		}
>> +	}
>> +	mutex_unlock(&act_id_mutex);
>> +}
>>
>>  int tcf_register_action(struct tc_action_ops *act,
>>  			struct pernet_operations *ops)
>> @@ -859,18 +958,30 @@ int tcf_register_action(struct tc_action_ops *act,
>>  	if (ret)
>>  		return ret;
>>
>> +	if (ops->id) {
>> +		ret = tcf_pernet_add_id_list(*ops->id);
>> +		if (ret)
>> +			goto id_err;
>> +	}
>> +
>>  	write_lock(&act_mod_lock);
>>  	list_for_each_entry(a, &act_base, head) {
>>  		if (act->id == a->id || (strcmp(act->kind, a->kind) == 0)) {
>> -			write_unlock(&act_mod_lock);
>> -			unregister_pernet_subsys(ops);
>> -			return -EEXIST;
>> +			ret = -EEXIST;
>> +			goto err_out;
>>  		}
>>  	}
>>  	list_add_tail(&act->head, &act_base);
>>  	write_unlock(&act_mod_lock);
>>
>>  	return 0;
>> +
>> +err_out:
>> +	write_unlock(&act_mod_lock);
>> +	tcf_pernet_del_id_list(*ops->id);
>> +id_err:
>
>Rename to 'err_id' to harmonize label naming.
Ok, will make the change.
>
>> +	unregister_pernet_subsys(ops);
>> +	return ret;
>>  }
>>  EXPORT_SYMBOL(tcf_register_action);
>>
>> @@ -889,12 +1000,76 @@ int tcf_unregister_action(struct tc_action_ops
>*act,
>>  		}
>>  	}
>>  	write_unlock(&act_mod_lock);
>> -	if (!err)
>> +	if (!err) {
>>  		unregister_pernet_subsys(ops);
>> +		if (ops->id)
>> +			tcf_pernet_del_id_list(*ops->id);
>> +	}
>>  	return err;
>>  }
>>  EXPORT_SYMBOL(tcf_unregister_action);
>>
>> +int tcf_action_reoffload_cb(flow_indr_block_bind_cb_t *cb,
>> +			    void *cb_priv, bool add)
>> +{
>> +	struct tc_act_pernet_id *id_ptr;
>> +	struct tcf_idrinfo *idrinfo;
>> +	struct tc_action_net *tn;
>> +	struct tc_action *p;
>> +	unsigned int act_id;
>> +	unsigned long tmp;
>> +	unsigned long id;
>> +	struct idr *idr;
>> +	struct net *net;
>> +	int ret;
>> +
>> +	if (!cb)
>> +		return -EINVAL;
>> +
>> +	down_read(&net_rwsem);
>> +	mutex_lock(&act_id_mutex);
>> +
>> +	for_each_net(net) {
>> +		list_for_each_entry(id_ptr, &act_pernet_id_list, list) {
>> +			act_id = id_ptr->id;
>> +			tn = net_generic(net, act_id);
>> +			if (!tn)
>> +				continue;
>> +			idrinfo = tn->idrinfo;
>> +			if (!idrinfo)
>> +				continue;
>> +
>> +			mutex_lock(&idrinfo->lock);
>> +			idr = &idrinfo->action_idr;
>> +			idr_for_each_entry_ul(idr, p, tmp, id) {
>> +				if (IS_ERR(p) || tc_act_bind(p->tcfa_flags))
>> +					continue;
>> +				if (add) {
>> +					tcf_action_offload_add_ex(p, NULL,
>cb,
>> +								  cb_priv);
>> +					continue;
>> +				}
>> +
>> +				/* cb unregister to update hw count */
>> +				ret = tcf_action_offload_del_ex(p, cb,
>cb_priv);
>> +				if (ret < 0)
>> +					continue;
>> +				if (tc_act_skip_sw(p->tcfa_flags) &&
>> +				    !tc_act_in_hw(p)) {
>> +					ret = tcf_idr_release_unsafe(p);
>
>Deleting skip_sw action that is no longer offloaded to any hardware device is
>reasonable, but note that in this case no netlink notification is ever generated.
>Don't know if it is a problem, just highlighting the fact since the whole
>behavior of implicitly deleting such actions is completely omitted from the
>change log.
Thanks for bring this to us. We will think about to add the notification implement and also we will
change commit message to mention about this.
>
>> +					if (ret == ACT_P_DELETED)
>> +						module_put(p->ops->owner);
>> +				}
>> +			}
>> +			mutex_unlock(&idrinfo->lock);
>> +		}
>> +	}
>> +	mutex_unlock(&act_id_mutex);
>> +	up_read(&net_rwsem);
>> +
>> +	return 0;
>> +}
>> +
>>  /* lookup by name */
>>  static struct tc_action_ops *tc_lookup_action_n(char *kind)  {

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