Merge branch 'net-sched-propagate-extack-to-cls-offloads-on-destroy-and-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>

2 files changed, 14 insertions, 13 deletions

diff --git a/include/net/pkt_cls.h b/include/net/pkt_cls.h
index 2f8f16a4d88e..1a41513cec7f 100644
--- a/include/net/pkt_cls.h
+++ b/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 {
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index cd1be1f25c36..eac43e8ca96d 100644
--- a/include/net/sch_generic.h
+++ b/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 *,