bpf: call verifier_prep from its callback in struct bpf_offload_dev

In a way similar to the change previously brought to the verify_insn
hook and to the finalize callback, switch to the newly added ops in
struct bpf_prog_offload for calling the functions used to prepare driver
verifiers.

Since the dev_ops pointer in struct bpf_prog_offload is no longer used
by any callback, we can now remove it from struct bpf_prog_offload.

Signed-off-by: Quentin Monnet <quentin.monnet@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

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

@@ -188,10 +188,11 @@ static void nfp_prog_free(struct nfp_prog *nfp_prog)
 }
 
 static int
-nfp_bpf_verifier_prep(struct nfp_app *app, struct nfp_net *nn,
-		      struct netdev_bpf *bpf)
+nfp_bpf_verifier_prep(struct net_device *netdev, struct bpf_verifier_env *env)
 {
-	struct bpf_prog *prog = bpf->verifier.prog;
+	struct nfp_net *nn = netdev_priv(netdev);
+	struct bpf_prog *prog = env->prog;
+	struct nfp_app *app = nn->app;
 	struct nfp_prog *nfp_prog;
 	int ret;
 
@@ -209,7 +210,6 @@ nfp_bpf_verifier_prep(struct nfp_app *app, struct nfp_net *nn,
 		goto err_free;
 
 	nfp_prog->verifier_meta = nfp_prog_first_meta(nfp_prog);
-	bpf->verifier.ops = &nfp_bpf_dev_ops;
 
 	return 0;
 
@@ -422,8 +422,6 @@ nfp_bpf_map_free(struct nfp_app_bpf *bpf, struct bpf_offloaded_map *offmap)
 int nfp_ndo_bpf(struct nfp_app *app, struct nfp_net *nn, struct netdev_bpf *bpf)
 {
 	switch (bpf->command) {
-	case BPF_OFFLOAD_VERIFIER_PREP:
-		return nfp_bpf_verifier_prep(app, nn, bpf);
 	case BPF_OFFLOAD_TRANSLATE:
 		return nfp_bpf_translate(nn, bpf->offload.prog);
 	case BPF_OFFLOAD_DESTROY:
@@ -605,4 +603,5 @@ int nfp_net_bpf_offload(struct nfp_net *nn, struct bpf_prog *prog,
 const struct bpf_prog_offload_ops nfp_bpf_dev_ops = {
 	.insn_hook	= nfp_verify_insn,
 	.finalize	= nfp_bpf_finalize,
+	.prepare	= nfp_bpf_verifier_prep,
 };

drivers/net/netdevsim/bpf.c

@@ -91,11 +91,6 @@ static int nsim_bpf_finalize(struct bpf_verifier_env *env)
 	return 0;
 }
 
-static const struct bpf_prog_offload_ops nsim_bpf_dev_ops = {
-	.insn_hook	= nsim_bpf_verify_insn,
-	.finalize	= nsim_bpf_finalize,
-};
-
 static bool nsim_xdp_offload_active(struct netdevsim *ns)
 {
 	return ns->xdp_hw.prog;
@@ -263,6 +258,17 @@ static int nsim_bpf_create_prog(struct netdevsim *ns, struct bpf_prog *prog)
 	return 0;
 }
 
+static int
+nsim_bpf_verifier_prep(struct net_device *dev, struct bpf_verifier_env *env)
+{
+	struct netdevsim *ns = netdev_priv(dev);
+
+	if (!ns->bpf_bind_accept)
+		return -EOPNOTSUPP;
+
+	return nsim_bpf_create_prog(ns, env->prog);
+}
+
 static void nsim_bpf_destroy_prog(struct bpf_prog *prog)
 {
 	struct nsim_bpf_bound_prog *state;
@@ -275,6 +281,12 @@ static void nsim_bpf_destroy_prog(struct bpf_prog *prog)
 	kfree(state);
 }
 
+static const struct bpf_prog_offload_ops nsim_bpf_dev_ops = {
+	.insn_hook	= nsim_bpf_verify_insn,
+	.finalize	= nsim_bpf_finalize,
+	.prepare	= nsim_bpf_verifier_prep,
+};
+
 static int nsim_setup_prog_checks(struct netdevsim *ns, struct netdev_bpf *bpf)
 {
 	if (bpf->prog && bpf->prog->aux->offload) {
@@ -539,16 +551,6 @@ int nsim_bpf(struct net_device *dev, struct netdev_bpf *bpf)
 	ASSERT_RTNL();
 
 	switch (bpf->command) {
-	case BPF_OFFLOAD_VERIFIER_PREP:
-		if (!ns->bpf_bind_accept)
-			return -EOPNOTSUPP;
-
-		err = nsim_bpf_create_prog(ns, bpf->verifier.prog);
-		if (err)
-			return err;
-
-		bpf->verifier.ops = &nsim_bpf_dev_ops;
-		return 0;
 	case BPF_OFFLOAD_TRANSLATE:
 		state = bpf->offload.prog->aux->offload->dev_priv;
 

include/linux/bpf.h

@@ -268,6 +268,7 @@ struct bpf_prog_offload_ops {
 	int (*insn_hook)(struct bpf_verifier_env *env,
 			 int insn_idx, int prev_insn_idx);
 	int (*finalize)(struct bpf_verifier_env *env);
+	int (*prepare)(struct net_device *netdev, struct bpf_verifier_env *env);
 };
 
 struct bpf_prog_offload {
@@ -277,7 +278,6 @@ struct bpf_prog_offload {
 	void			*dev_priv;
 	struct list_head	offloads;
 	bool			dev_state;
-	const struct bpf_prog_offload_ops *dev_ops;
 	void			*jited_image;
 	u32			jited_len;
 };

include/linux/netdevice.h

@@ -863,7 +863,6 @@ enum bpf_netdev_command {
 	XDP_QUERY_PROG,
 	XDP_QUERY_PROG_HW,
 	/* BPF program for offload callbacks, invoked at program load time. */
-	BPF_OFFLOAD_VERIFIER_PREP,
 	BPF_OFFLOAD_TRANSLATE,
 	BPF_OFFLOAD_DESTROY,
 	BPF_OFFLOAD_MAP_ALLOC,
@@ -891,11 +890,6 @@ struct netdev_bpf {
 			/* flags with which program was installed */
 			u32 prog_flags;
 		};
-		/* BPF_OFFLOAD_VERIFIER_PREP */
-		struct {
-			struct bpf_prog *prog;
-			const struct bpf_prog_offload_ops *ops; /* callee set */
-		} verifier;
 		/* BPF_OFFLOAD_TRANSLATE, BPF_OFFLOAD_DESTROY */
 		struct {
 			struct bpf_prog *prog;

kernel/bpf/offload.c

@@ -142,21 +142,17 @@ static int __bpf_offload_ndo(struct bpf_prog *prog, enum bpf_netdev_command cmd,
 
 int bpf_prog_offload_verifier_prep(struct bpf_verifier_env *env)
 {
-	struct netdev_bpf data = {};
-	int err;
+	struct bpf_prog_offload *offload;
+	int ret = -ENODEV;
 
-	data.verifier.prog = env->prog;
+	down_read(&bpf_devs_lock);
+	offload = env->prog->aux->offload;
+	if (offload)
+		ret = offload->offdev->ops->prepare(offload->netdev, env);
+	offload->dev_state = !ret;
+	up_read(&bpf_devs_lock);
 
-	rtnl_lock();
-	err = __bpf_offload_ndo(env->prog, BPF_OFFLOAD_VERIFIER_PREP, &data);
-	if (err)
-		goto exit_unlock;
-
-	env->prog->aux->offload->dev_ops = data.verifier.ops;
-	env->prog->aux->offload->dev_state = true;
-exit_unlock:
-	rtnl_unlock();
-	return err;
+	return ret;
 }
 
 int bpf_prog_offload_verify_insn(struct bpf_verifier_env *env,