From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Tue, 19 Dec 2017 13:32:13 -0800
Subject: cls_bpf: fix offload assumptions after callback conversion
Patch-mainline: v4.15-rc5
Git-commit: 102740bd9436a3a6ba129af3a48271d794009fa5
References: bsc#1109837

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: 3f7889c4c79b ("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>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.c |   12 ---
 include/net/pkt_cls.h                         |    5 -
 net/sched/cls_bpf.c                           |   93 ++++++++++----------------
 3 files changed, 43 insertions(+), 67 deletions(-)

--- a/drivers/net/ethernet/netronome/nfp/bpf/main.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.c
@@ -110,16 +110,10 @@ static int nfp_bpf_setup_tc_block_cb(enu
 		return -EOPNOTSUPP;
 	}
 
-	switch (cls_bpf->command) {
-	case TC_CLSBPF_REPLACE:
-		return nfp_net_bpf_offload(nn, cls_bpf->prog, true);
-	case TC_CLSBPF_ADD:
-		return nfp_net_bpf_offload(nn, cls_bpf->prog, false);
-	case TC_CLSBPF_DESTROY:
-		return nfp_net_bpf_offload(nn, NULL, true);
-	default:
+	if (cls_bpf->command != TC_CLSBPF_OFFLOAD)
 		return -EOPNOTSUPP;
-	}
+
+	return nfp_net_bpf_offload(nn, cls_bpf->prog, cls_bpf->oldprog);
 }
 
 static int nfp_bpf_setup_tc_block(struct net_device *netdev,
--- a/include/net/pkt_cls.h
+++ b/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;
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -42,7 +42,6 @@ struct cls_bpf_prog {
 	struct list_head link;
 	struct tcf_result res;
 	bool exts_integrated;
-	bool offloaded;
 	u32 gen_flags;
 	struct tcf_exts exts;
 	u32 handle;
@@ -148,33 +147,37 @@ static bool cls_bpf_is_ebpf(const struct
 }
 
 static int cls_bpf_offload_cmd(struct tcf_proto *tp, struct cls_bpf_prog *prog,
-			       enum tc_clsbpf_command cmd)
+			       struct cls_bpf_prog *oldprog)
 {
-	bool addorrep = cmd == TC_CLSBPF_ADD || cmd == TC_CLSBPF_REPLACE;
 	struct tcf_block *block = tp->chain->block;
-	bool skip_sw = tc_skip_sw(prog->gen_flags);
 	struct tc_cls_bpf_offload cls_bpf = {};
+	struct cls_bpf_prog *obj;
+	bool skip_sw;
 	int err;
 
+	skip_sw = prog && tc_skip_sw(prog->gen_flags);
+	obj = prog ?: oldprog;
+
 	tc_cls_common_offload_init(&cls_bpf.common, tp);
-	cls_bpf.command = cmd;
-	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;
+	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;
 
 	err = tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, skip_sw);
-	if (addorrep) {
+	if (prog) {
 		if (err < 0) {
-			cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
+			cls_bpf_offload_cmd(tp, oldprog, prog);
 			return err;
 		} else if (err > 0) {
 			prog->gen_flags |= TCA_CLS_FLAGS_IN_HW;
 		}
 	}
 
-	if (addorrep && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
+	if (prog && skip_sw && !(prog->gen_flags & TCA_CLS_FLAGS_IN_HW))
 		return -EINVAL;
 
 	return 0;
@@ -183,38 +186,17 @@ static int cls_bpf_offload_cmd(struct tc
 static int cls_bpf_offload(struct tcf_proto *tp, struct cls_bpf_prog *prog,
 			   struct cls_bpf_prog *oldprog)
 {
-	struct cls_bpf_prog *obj = prog;
-	enum tc_clsbpf_command cmd;
-	bool skip_sw;
-	int ret;
-
-	skip_sw = tc_skip_sw(prog->gen_flags) ||
-		(oldprog && tc_skip_sw(oldprog->gen_flags));
-
-	if (oldprog && oldprog->offloaded) {
-		if (!tc_skip_hw(prog->gen_flags)) {
-			cmd = TC_CLSBPF_REPLACE;
-		} else if (!tc_skip_sw(prog->gen_flags)) {
-			obj = oldprog;
-			cmd = TC_CLSBPF_DESTROY;
-		} else {
-			return -EINVAL;
-		}
-	} else {
-		if (tc_skip_hw(prog->gen_flags))
-			return skip_sw ? -EINVAL : 0;
-		cmd = TC_CLSBPF_ADD;
-	}
+	if (prog && oldprog && prog->gen_flags != oldprog->gen_flags)
+		return -EINVAL;
 
-	ret = cls_bpf_offload_cmd(tp, obj, cmd);
-	if (ret)
-		return ret;
-
-	obj->offloaded = true;
-	if (oldprog)
-		oldprog->offloaded = false;
+	if (prog && tc_skip_hw(prog->gen_flags))
+		prog = NULL;
+	if (oldprog && tc_skip_hw(oldprog->gen_flags))
+		oldprog = NULL;
+	if (!prog && !oldprog)
+		return 0;
 
-	return 0;
+	return cls_bpf_offload_cmd(tp, prog, oldprog);
 }
 
 static void cls_bpf_stop_offload(struct tcf_proto *tp,
@@ -222,25 +204,26 @@ static void cls_bpf_stop_offload(struct
 {
 	int err;
 
-	if (!prog->offloaded)
-		return;
-
-	err = cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_DESTROY);
-	if (err) {
+	err = cls_bpf_offload_cmd(tp, NULL, prog);
+	if (err)
 		pr_err("Stopping hardware offload failed: %d\n", err);
-		return;
-	}
-
-	prog->offloaded = false;
 }
 
 static void cls_bpf_offload_update_stats(struct tcf_proto *tp,
 					 struct cls_bpf_prog *prog)
 {
-	if (!prog->offloaded)
-		return;
+	struct tcf_block *block = tp->chain->block;
+	struct tc_cls_bpf_offload cls_bpf = {};
+
+	tc_cls_common_offload_init(&cls_bpf.common, tp);
+	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;
 
-	cls_bpf_offload_cmd(tp, prog, TC_CLSBPF_STATS);
+	tc_setup_cb_call(block, NULL, TC_SETUP_CLSBPF, &cls_bpf, false);
 }
 
 static int cls_bpf_init(struct tcf_proto *tp)