Merge branch 'cls_bpf-fix-offload-state-tracking-with-block-callbacks'

Jakub Kicinski says:

===================
cls_bpf: fix offload state tracking with block callbacks

After introduction of block callbacks classifiers can no longer track
offload state.  cls_bpf used to do that in an attempt to move common
code from drivers to the core.  Remove that functionality and fix
drivers.

The user-visible bug this is fixing is that trying to offload a second
filter would trigger a spurious DESTROY and in turn disable the already
installed one.
===================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/netronome/nfp/bpf/main.c

@@ -82,10 +82,33 @@ static const char *nfp_bpf_extra_cap(struct nfp_app *app, struct nfp_net *nn)
 	return nfp_net_ebpf_capable(nn) ? "BPF" : "";
 }
 
+static int
+nfp_bpf_vnic_alloc(struct nfp_app *app, struct nfp_net *nn, unsigned int id)
+{
+	int err;
+
+	nn->app_priv = kzalloc(sizeof(struct nfp_bpf_vnic), GFP_KERNEL);
+	if (!nn->app_priv)
+		return -ENOMEM;
+
+	err = nfp_app_nic_vnic_alloc(app, nn, id);
+	if (err)
+		goto err_free_priv;
+
+	return 0;
+err_free_priv:
+	kfree(nn->app_priv);
+	return err;
+}
+
 static void nfp_bpf_vnic_free(struct nfp_app *app, struct nfp_net *nn)
 {
+	struct nfp_bpf_vnic *bv = nn->app_priv;
+
 	if (nn->dp.bpf_offload_xdp)
 		nfp_bpf_xdp_offload(app, nn, NULL);
+	WARN_ON(bv->tc_prog);
+	kfree(bv);
 }
 
 static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type type,
@@ -93,6 +116,9 @@ static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type type,
 {
 	struct tc_cls_bpf_offload *cls_bpf = type_data;
 	struct nfp_net *nn = cb_priv;
+	struct bpf_prog *oldprog;
+	struct nfp_bpf_vnic *bv;
+	int err;
 
 	if (type != TC_SETUP_CLSBPF ||
 	    !tc_can_offload(nn->dp.netdev) ||
@@ -100,8 +126,6 @@ static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type type,
 	    cls_bpf->common.protocol != htons(ETH_P_ALL) ||
 	    cls_bpf->common.chain_index)
 		return -EOPNOTSUPP;
-	if (nn->dp.bpf_offload_xdp)
-		return -EBUSY;
 
 	/* Only support TC direct action */
 	if (!cls_bpf->exts_integrated ||
@@ -110,16 +134,25 @@ static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type type,
 		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;
+
+	bv = nn->app_priv;
+	oldprog = cls_bpf->oldprog;
+
+	/* Don't remove if oldprog doesn't match driver's state */
+	if (bv->tc_prog != oldprog) {
+		oldprog = NULL;
+		if (!cls_bpf->prog)
+			return 0;
 	}
+
+	err = nfp_net_bpf_offload(nn, cls_bpf->prog, oldprog);
+	if (err)
+		return err;
+
+	bv->tc_prog = cls_bpf->prog;
+	return 0;
 }
 
 static int nfp_bpf_setup_tc_block(struct net_device *netdev,
@@ -167,7 +200,7 @@ const struct nfp_app_type app_bpf = {
 
 	.extra_cap	= nfp_bpf_extra_cap,
 
-	.vnic_alloc	= nfp_app_nic_vnic_alloc,
+	.vnic_alloc	= nfp_bpf_vnic_alloc,
 	.vnic_free	= nfp_bpf_vnic_free,
 
 	.setup_tc	= nfp_bpf_setup_tc,

drivers/net/ethernet/netronome/nfp/bpf/main.h

@@ -172,6 +172,14 @@ struct nfp_prog {
 	struct list_head insns;
 };
 
+/**
+ * struct nfp_bpf_vnic - per-vNIC BPF priv structure
+ * @tc_prog:	currently loaded cls_bpf program
+ */
+struct nfp_bpf_vnic {
+	struct bpf_prog *tc_prog;
+};
+
 int nfp_bpf_jit(struct nfp_prog *prog);
 
 extern const struct bpf_ext_analyzer_ops nfp_bpf_analyzer_ops;

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;

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 cls_bpf_prog *prog)
 }
 
 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 tcf_proto *tp, struct cls_bpf_prog *prog,
 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;
-	}
-
-	ret = cls_bpf_offload_cmd(tp, obj, cmd);
-	if (ret)
-		return ret;
+	if (prog && oldprog && prog->gen_flags != oldprog->gen_flags)
+		return -EINVAL;
 
-	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 tcf_proto *tp,
 {
 	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)