cls_bpf: fix offload assumptions after callback conversion

cls_bpf used to take care of tracking what offload state a filter
is in, i.e. it would track if offload request succeeded or not.
This information would then be used to issue correct requests to
the driver, e.g. requests for statistics only on offloaded filters,
removing only filters which were offloaded, using add instead of
replace if previous filter was not added etc.

This tracking of offload state no longer functions with the new
callback infrastructure.  There could be multiple entities trying
to offload the same filter.

Throw out all the tracking and corresponding commands and simply
pass to the drivers both old and new bpf program.  Drivers will
have to deal with offload state tracking by themselves.

Fixes: 3f7889c4c7 ("net: sched: cls_bpf: call block callbacks for offload")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/pkt_cls.h

@@ -694,9 +694,7 @@ struct tc_cls_matchall_offload {
 };
 
 enum tc_clsbpf_command {
-	TC_CLSBPF_ADD,
-	TC_CLSBPF_REPLACE,
-	TC_CLSBPF_DESTROY,
+	TC_CLSBPF_OFFLOAD,
 	TC_CLSBPF_STATS,
 };
 
@@ -705,6 +703,7 @@ struct tc_cls_bpf_offload {
 	enum tc_clsbpf_command command;
 	struct tcf_exts *exts;
 	struct bpf_prog *prog;
+	struct bpf_prog *oldprog;
 	const char *name;
 	bool exts_integrated;
 	u32 gen_flags;