Merge branch 'net-sched-propagate-extack-to-cls-offloads-on-destroy-a…

…nd-only-with-skip_sw'

Jakub Kicinski says:

====================
net: sched: propagate extack to cls offloads on destroy and only with skip_sw

This series some of Jiri's comments and the fact that today drivers
may produce extack even if there is no skip_sw flag (meaning the
driver failure is not really a problem), and warning messages will
only confuse the users.

First patch propagates extack to destroy as requested by Jiri, extack
is then propagated to the driver callback for each classifier.  I chose
not to provide the extack on error paths.  As a rule of thumb it seems
best to keep the extack of the condition which caused the error.  E.g.

     err = this_will_fail(arg, extack);
     if (err) {
        undo_things(arg, NULL /* don't pass extack */);
	return err;
     }

Note that NL_SET_ERR_MSG() will ignore the message if extack is NULL.
I was pondering whether we should make NL_SET_ERR_MSG() refuse to
overwrite the msg, but there seem to be cases in the tree where extack
is set like this:

     err = this_will_fail(arg, extack);
     if (err) {
        undo_things(arg, NULL /* don't pass extack */);
	NL_SET_ERR_MSG(extack, "extack is set after undo call :/");
	return err;
     }

I think not passing extack to undo calls is reasonable.

v2:
 - rename the temporary tc_cls_common_offload_init().
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/pkt_cls.h

@@ -605,17 +605,6 @@ struct tc_cls_common_offload {
 	struct netlink_ext_ack *extack;
 };
 
-static inline void
-tc_cls_common_offload_init(struct tc_cls_common_offload *cls_common,
-			   const struct tcf_proto *tp,
-			   struct netlink_ext_ack *extack)
-{
-	cls_common->chain_index = tp->chain->index;
-	cls_common->protocol = tp->protocol;
-	cls_common->prio = tp->prio;
-	cls_common->extack = extack;
-}
-
 struct tc_cls_u32_knode {
 	struct tcf_exts *exts;
 	struct tc_u32_sel *sel;
@@ -694,6 +683,18 @@ static inline bool tc_in_hw(u32 flags)
 	return (flags & TCA_CLS_FLAGS_IN_HW) ? true : false;
 }
 
+static inline void
+tc_cls_common_offload_init(struct tc_cls_common_offload *cls_common,
+			   const struct tcf_proto *tp, u32 flags,
+			   struct netlink_ext_ack *extack)
+{
+	cls_common->chain_index = tp->chain->index;
+	cls_common->protocol = tp->protocol;
+	cls_common->prio = tp->prio;
+	if (tc_skip_sw(flags))
+		cls_common->extack = extack;
+}
+
 enum tc_fl_command {
 	TC_CLSFLOWER_REPLACE,
 	TC_CLSFLOWER_DESTROY,
@@ -736,7 +737,6 @@ struct tc_cls_bpf_offload {
 	struct bpf_prog *oldprog;
 	const char *name;
 	bool exts_integrated;
-	u32 gen_flags;
 };
 
 struct tc_mqprio_qopt_offload {

include/net/sch_generic.h

@@ -233,7 +233,8 @@ struct tcf_proto_ops {
 					    const struct tcf_proto *,
 					    struct tcf_result *);
 	int			(*init)(struct tcf_proto*);
-	void			(*destroy)(struct tcf_proto*);
+	void			(*destroy)(struct tcf_proto *tp,
+					   struct netlink_ext_ack *extack);
 
 	void*			(*get)(struct tcf_proto*, u32 handle);
 	int			(*change)(struct net *net, struct sk_buff *,

net/sched/cls_api.c

@@ -172,9 +172,10 @@ static struct tcf_proto *tcf_proto_create(const char *kind, u32 protocol,
 	return ERR_PTR(err);
 }
 
-static void tcf_proto_destroy(struct tcf_proto *tp)
+static void tcf_proto_destroy(struct tcf_proto *tp,
+			      struct netlink_ext_ack *extack)
 {
-	tp->ops->destroy(tp);
+	tp->ops->destroy(tp, extack);
 	module_put(tp->ops->owner);
 	kfree_rcu(tp, rcu);
 }
@@ -223,7 +224,7 @@ static void tcf_chain_flush(struct tcf_chain *chain)
 	tcf_chain_head_change(chain, NULL);
 	while (tp) {
 		RCU_INIT_POINTER(chain->filter_chain, tp->next);
-		tcf_proto_destroy(tp);
+		tcf_proto_destroy(tp, NULL);
 		tp = rtnl_dereference(chain->filter_chain);
 		tcf_chain_put(chain);
 	}
@@ -1182,7 +1183,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 			tcf_chain_tp_remove(chain, &chain_info, tp);
 			tfilter_notify(net, skb, n, tp, block, q, parent, fh,
 				       RTM_DELTFILTER, false);
-			tcf_proto_destroy(tp);
+			tcf_proto_destroy(tp, extack);
 			err = 0;
 			goto errout;
 		}
@@ -1200,7 +1201,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 		case RTM_NEWTFILTER:
 			if (n->nlmsg_flags & NLM_F_EXCL) {
 				if (tp_created)
-					tcf_proto_destroy(tp);
+					tcf_proto_destroy(tp, NULL);
 				NL_SET_ERR_MSG(extack, "Filter already exists");
 				err = -EEXIST;
 				goto errout;
@@ -1214,7 +1215,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 				goto errout;
 			if (last) {
 				tcf_chain_tp_remove(chain, &chain_info, tp);
-				tcf_proto_destroy(tp);
+				tcf_proto_destroy(tp, extack);
 			}
 			goto errout;
 		case RTM_GETTFILTER:
@@ -1240,7 +1241,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 			       RTM_NEWTFILTER, false);
 	} else {
 		if (tp_created)
-			tcf_proto_destroy(tp);
+			tcf_proto_destroy(tp, NULL);
 	}
 
 errout:

net/sched/cls_basic.c

@@ -112,7 +112,7 @@ static void basic_delete_filter(struct rcu_head *head)
 	tcf_queue_work(&f->work);
 }
 
-static void basic_destroy(struct tcf_proto *tp)
+static void basic_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
 	struct basic_head *head = rtnl_dereference(tp->root);
 	struct basic_filter *f, *n;

net/sched/cls_bpf.c

@@ -159,14 +159,14 @@ static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 	skip_sw = prog && tc_skip_sw(prog->gen_flags);
 	obj = prog ?: oldprog;
 
-	tc_cls_common_offload_init(&cls_bpf.common, tp, extack);
+	tc_cls_common_offload_init(&cls_bpf.common, tp, obj->gen_flags,
+				   extack);
 	cls_bpf.command = TC_CLSBPF_OFFLOAD;
 	cls_bpf.exts = &obj->exts;
 	cls_bpf.prog = prog ? prog->filter : NULL;
 	cls_bpf.oldprog = oldprog ? oldprog->filter : NULL;
 	cls_bpf.name = obj->bpf_name;
 	cls_bpf.exts_integrated = obj->exts_integrated;
-	cls_bpf.gen_flags = obj->gen_flags;
 
 	if (oldprog)
 		tcf_block_offload_dec(block, &oldprog->gen_flags);
@@ -212,11 +212,12 @@ static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 }
 
 static void cls_bpf_stop_offload(struct tcf_proto *tp,
-				 struct cls_bpf_prog *prog)
+				 struct cls_bpf_prog *prog,
+				 struct netlink_ext_ack *extack)
 {
 	int err;
 
-	err = cls_bpf_offload_cmd(tp, NULL, prog, NULL);
+	err = cls_bpf_offload_cmd(tp, NULL, prog, extack);
 	if (err)
 		pr_err("Stopping hardware offload failed: %d\n", err);
 }
@@ -227,13 +228,12 @@ static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 	struct tcf_block *block = tp->chain->block;
 	struct tc_cls_bpf_offload cls_bpf = {};
 
-	tc_cls_common_offload_init(&cls_bpf.common, tp, NULL);
+	tc_cls_common_offload_init(&cls_bpf.common, tp, prog->gen_flags, NULL);
 	cls_bpf.command = TC_CLSBPF_STATS;
 	cls_bpf.exts = &prog->exts;
 	cls_bpf.prog = prog->filter;
 	cls_bpf.name = prog->bpf_name;
 	cls_bpf.exts_integrated = prog->exts_integrated;
-	cls_bpf.gen_flags = prog->gen_flags;
 
 	tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
 }
@@ -290,12 +290,13 @@ static void cls_bpf_delete_prog_rcu(struct rcu_head *rcu)
 	tcf_queue_work(&prog->work);
 }
 
-static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog)
+static void __cls_bpf_delete(struct tcf_proto *tp, struct cls_bpf_prog *prog,
+			     struct netlink_ext_ack *extack)
 {
 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
 
 	idr_remove_ext(&head->handle_idr, prog->handle);
-	cls_bpf_stop_offload(tp, prog);
+	cls_bpf_stop_offload(tp, prog, extack);
 	list_del_rcu(&prog->link);
 	tcf_unbind_filter(tp, &prog->res);
 	if (tcf_exts_get_net(&prog->exts))
@@ -309,18 +310,19 @@ static int cls_bpf_delete(struct tcf_proto *tp, void *arg, bool *last,
 {
 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
 
-	__cls_bpf_delete(tp, arg);
+	__cls_bpf_delete(tp, arg, extack);
 	*last = list_empty(&head->plist);
 	return 0;
 }
 
-static void cls_bpf_destroy(struct tcf_proto *tp)
+static void cls_bpf_destroy(struct tcf_proto *tp,
+			    struct netlink_ext_ack *extack)
 {
 	struct cls_bpf_head *head = rtnl_dereference(tp->root);
 	struct cls_bpf_prog *prog, *tmp;
 
 	list_for_each_entry_safe(prog, tmp, &head->plist, link)
-		__cls_bpf_delete(tp, prog);
+		__cls_bpf_delete(tp, prog, extack);
 
 	idr_destroy(&head->handle_idr);
 	kfree_rcu(head, rcu);

net/sched/cls_cgroup.c

@@ -143,7 +143,8 @@ static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
 	return err;
 }
 
-static void cls_cgroup_destroy(struct tcf_proto *tp)
+static void cls_cgroup_destroy(struct tcf_proto *tp,
+			       struct netlink_ext_ack *extack)
 {
 	struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 

net/sched/cls_flow.c

@@ -600,7 +600,7 @@ static int flow_init(struct tcf_proto *tp)
 	return 0;
 }
 
-static void flow_destroy(struct tcf_proto *tp)
+static void flow_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
 	struct flow_head *head = rtnl_dereference(tp->root);
 	struct flow_filter *f, *next;

net/sched/cls_flower.c

@@ -218,12 +218,13 @@ static void fl_destroy_filter(struct rcu_head *head)
 	tcf_queue_work(&f->work);
 }
 
-static void fl_hw_destroy_filter(struct tcf_proto *tp, struct cls_fl_filter *f)
+static void fl_hw_destroy_filter(struct tcf_proto *tp, struct cls_fl_filter *f,
+				 struct netlink_ext_ack *extack)
 {
 	struct tc_cls_flower_offload cls_flower = {};
 	struct tcf_block *block = tp->chain->block;
 
-	tc_cls_common_offload_init(&cls_flower.common, tp, NULL);
+	tc_cls_common_offload_init(&cls_flower.common, tp, f->flags, extack);
 	cls_flower.command = TC_CLSFLOWER_DESTROY;
 	cls_flower.cookie = (unsigned long) f;
 
@@ -243,7 +244,7 @@ static int fl_hw_replace_filter(struct tcf_proto *tp,
 	bool skip_sw = tc_skip_sw(f->flags);
 	int err;
 
-	tc_cls_common_offload_init(&cls_flower.common, tp, extack);
+	tc_cls_common_offload_init(&cls_flower.common, tp, f->flags, extack);
 	cls_flower.command = TC_CLSFLOWER_REPLACE;
 	cls_flower.cookie = (unsigned long) f;
 	cls_flower.dissector = dissector;
@@ -255,7 +256,7 @@ static int fl_hw_replace_filter(struct tcf_proto *tp,
 	err = tc_setup_cb_call(block, &f->exts, TC_SETUP_CLSFLOWER,
 			       &cls_flower, skip_sw);
 	if (err < 0) {
-		fl_hw_destroy_filter(tp, f);
+		fl_hw_destroy_filter(tp, f, NULL);
 		return err;
 	} else if (err > 0) {
 		tcf_block_offload_inc(block, &f->flags);
@@ -272,7 +273,7 @@ static void fl_hw_update_stats(struct tcf_proto *tp, struct cls_fl_filter *f)
 	struct tc_cls_flower_offload cls_flower = {};
 	struct tcf_block *block = tp->chain->block;
 
-	tc_cls_common_offload_init(&cls_flower.common, tp, NULL);
+	tc_cls_common_offload_init(&cls_flower.common, tp, f->flags, NULL);
 	cls_flower.command = TC_CLSFLOWER_STATS;
 	cls_flower.cookie = (unsigned long) f;
 	cls_flower.exts = &f->exts;
@@ -282,14 +283,15 @@ static void fl_hw_update_stats(struct tcf_proto *tp, struct cls_fl_filter *f)
 			 &cls_flower, false);
 }
 
-static void __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f)
+static void __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f,
+			struct netlink_ext_ack *extack)
 {
 	struct cls_fl_head *head = rtnl_dereference(tp->root);
 
 	idr_remove_ext(&head->handle_idr, f->handle);
 	list_del_rcu(&f->list);
 	if (!tc_skip_hw(f->flags))
-		fl_hw_destroy_filter(tp, f);
+		fl_hw_destroy_filter(tp, f, extack);
 	tcf_unbind_filter(tp, &f->res);
 	if (tcf_exts_get_net(&f->exts))
 		call_rcu(&f->rcu, fl_destroy_filter);
@@ -315,13 +317,13 @@ static void fl_destroy_rcu(struct rcu_head *rcu)
 	schedule_work(&head->work);
 }
 
-static void fl_destroy(struct tcf_proto *tp)
+static void fl_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
 	struct cls_fl_head *head = rtnl_dereference(tp->root);
 	struct cls_fl_filter *f, *next;
 
 	list_for_each_entry_safe(f, next, &head->filters, list)
-		__fl_delete(tp, f);
+		__fl_delete(tp, f, extack);
 	idr_destroy(&head->handle_idr);
 
 	__module_get(THIS_MODULE);
@@ -958,7 +960,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb,
 			rhashtable_remove_fast(&head->ht, &fold->ht_node,
 					       head->ht_params);
 		if (!tc_skip_hw(fold->flags))
-			fl_hw_destroy_filter(tp, fold);
+			fl_hw_destroy_filter(tp, fold, NULL);
 	}
 
 	*arg = fnew;
@@ -997,7 +999,7 @@ static int fl_delete(struct tcf_proto *tp, void *arg, bool *last,
 	if (!tc_skip_sw(f->flags))
 		rhashtable_remove_fast(&head->ht, &f->ht_node,
 				       head->ht_params);
-	__fl_delete(tp, f);
+	__fl_delete(tp, f, extack);
 	*last = list_empty(&head->filters);
 	return 0;
 }

net/sched/cls_fw.c

@@ -149,7 +149,7 @@ static void fw_delete_filter(struct rcu_head *head)
 	tcf_queue_work(&f->work);
 }
 
-static void fw_destroy(struct tcf_proto *tp)
+static void fw_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
 	struct fw_head *head = rtnl_dereference(tp->root);
 	struct fw_filter *f;

net/sched/cls_matchall.c

@@ -71,12 +71,13 @@ static void mall_destroy_rcu(struct rcu_head *rcu)
 
 static void mall_destroy_hw_filter(struct tcf_proto *tp,
 				   struct cls_mall_head *head,
-				   unsigned long cookie)
+				   unsigned long cookie,
+				   struct netlink_ext_ack *extack)
 {
 	struct tc_cls_matchall_offload cls_mall = {};
 	struct tcf_block *block = tp->chain->block;
 
-	tc_cls_common_offload_init(&cls_mall.common, tp, NULL);
+	tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
 	cls_mall.command = TC_CLSMATCHALL_DESTROY;
 	cls_mall.cookie = cookie;
 
@@ -94,15 +95,15 @@ static int mall_replace_hw_filter(struct tcf_proto *tp,
 	bool skip_sw = tc_skip_sw(head->flags);
 	int err;
 
-	tc_cls_common_offload_init(&cls_mall.common, tp, extack);
+	tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
 	cls_mall.command = TC_CLSMATCHALL_REPLACE;
 	cls_mall.exts = &head->exts;
 	cls_mall.cookie = cookie;
 
 	err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSMATCHALL,
 			       &cls_mall, skip_sw);
 	if (err < 0) {
-		mall_destroy_hw_filter(tp, head, cookie);
+		mall_destroy_hw_filter(tp, head, cookie, NULL);
 		return err;
 	} else if (err > 0) {
 		tcf_block_offload_inc(block, &head->flags);
@@ -114,15 +115,15 @@ static int mall_replace_hw_filter(struct tcf_proto *tp,
 	return 0;
 }
 
-static void mall_destroy(struct tcf_proto *tp)
+static void mall_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
 	struct cls_mall_head *head = rtnl_dereference(tp->root);
 
 	if (!head)
 		return;
 
 	if (!tc_skip_hw(head->flags))
-		mall_destroy_hw_filter(tp, head, (unsigned long) head);
+		mall_destroy_hw_filter(tp, head, (unsigned long) head, extack);
 
 	if (tcf_exts_get_net(&head->exts))
 		call_rcu(&head->rcu, mall_destroy_rcu);

net/sched/cls_route.c

@@ -281,7 +281,7 @@ static void route4_delete_filter(struct rcu_head *head)
 	tcf_queue_work(&f->work);
 }
 
-static void route4_destroy(struct tcf_proto *tp)
+static void route4_destroy(struct tcf_proto *tp, struct netlink_ext_ack *extack)
 {
 	struct route4_head *head = rtnl_dereference(tp->root);
 	int h1, h2;