[PATCH bpf-next] bpf: offload: add priv field for drivers

[PATCH bpf-next] bpf: offload: add priv field for drivers

[Jakub Kicinski]

Currently bpf_offload_dev does not have any priv pointer, forcing
the drivers to work backwards from the netdev in program metadata.
This is not great given programs are conceptually associated with
the offload device, and it means one or two unnecessary deferences.
Add a priv pointer to bpf_offload_dev.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.c    |  2 +-
 drivers/net/ethernet/netronome/nfp/bpf/offload.c |  4 +---
 drivers/net/netdevsim/bpf.c                      |  5 +++--
 include/linux/bpf.h                              |  3 ++-
 kernel/bpf/offload.c                             | 10 +++++++++-
 5 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.c b/drivers/net/ethernet/netronome/nfp/bpf/main.c
index dccae0319204..275de9f4c61c 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.c
@@ -465,7 +465,7 @@ static int nfp_bpf_init(struct nfp_app *app)
 		app->ctrl_mtu = nfp_bpf_ctrl_cmsg_mtu(bpf);
 	}
 
-	bpf->bpf_dev = bpf_offload_dev_create(&nfp_bpf_dev_ops);
+	bpf->bpf_dev = bpf_offload_dev_create(&nfp_bpf_dev_ops, bpf);
 	err = PTR_ERR_OR_ZERO(bpf->bpf_dev);
 	if (err)
 		goto err_free_neutral_maps;
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/offload.c b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
index 55c7dbf8b421..15dce97650a5 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/offload.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/offload.c
@@ -185,8 +185,6 @@ static void nfp_prog_free(struct nfp_prog *nfp_prog)
 
 static int nfp_bpf_verifier_prep(struct bpf_prog *prog)
 {
-	struct nfp_net *nn = netdev_priv(prog->aux->offload->netdev);
-	struct nfp_app *app = nn->app;
 	struct nfp_prog *nfp_prog;
 	int ret;
 
@@ -197,7 +195,7 @@ static int nfp_bpf_verifier_prep(struct bpf_prog *prog)
 
 	INIT_LIST_HEAD(&nfp_prog->insns);
 	nfp_prog->type = prog->type;
-	nfp_prog->bpf = app->priv;
+	nfp_prog->bpf = bpf_offload_dev_priv(prog->aux->offload->offdev);
 
 	ret = nfp_prog_prepare(nfp_prog, prog->insnsi, prog->len);
 	if (ret)
diff --git a/drivers/net/netdevsim/bpf.c b/drivers/net/netdevsim/bpf.c
index 172b271c8bd2..f92c43453ec6 100644
--- a/drivers/net/netdevsim/bpf.c
+++ b/drivers/net/netdevsim/bpf.c
@@ -248,7 +248,7 @@ static int nsim_bpf_create_prog(struct netdevsim *ns, struct bpf_prog *prog)
 
 static int nsim_bpf_verifier_prep(struct bpf_prog *prog)
 {
-	struct netdevsim *ns = netdev_priv(prog->aux->offload->netdev);
+	struct netdevsim *ns = bpf_offload_dev_priv(prog->aux->offload->offdev);
 
 	if (!ns->bpf_bind_accept)
 		return -EOPNOTSUPP;
@@ -589,7 +589,8 @@ int nsim_bpf_init(struct netdevsim *ns)
 		if (IS_ERR_OR_NULL(ns->sdev->ddir_bpf_bound_progs))
 			return -ENOMEM;
 
-		ns->sdev->bpf_dev = bpf_offload_dev_create(&nsim_bpf_dev_ops);
+		ns->sdev->bpf_dev = bpf_offload_dev_create(&nsim_bpf_dev_ops,
+							   ns);
 		err = PTR_ERR_OR_ZERO(ns->sdev->bpf_dev);
 		if (err)
 			return err;
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index bd169a7bcc93..d3126ff4994a 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -767,8 +767,9 @@ int bpf_map_offload_get_next_key(struct bpf_map *map,
 bool bpf_offload_prog_map_match(struct bpf_prog *prog, struct bpf_map *map);
 
 struct bpf_offload_dev *
-bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops);
+bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv);
 void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev);
+void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev);
 int bpf_offload_dev_netdev_register(struct bpf_offload_dev *offdev,
 				    struct net_device *netdev);
 void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index 39dba8c90331..ba635209ae9a 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -35,6 +35,7 @@ static DECLARE_RWSEM(bpf_devs_lock);
 struct bpf_offload_dev {
 	const struct bpf_prog_offload_ops *ops;
 	struct list_head netdevs;
+	void *priv;
 };
 
 struct bpf_offload_netdev {
@@ -669,7 +670,7 @@ void bpf_offload_dev_netdev_unregister(struct bpf_offload_dev *offdev,
 EXPORT_SYMBOL_GPL(bpf_offload_dev_netdev_unregister);
 
 struct bpf_offload_dev *
-bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops)
+bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops, void *priv)
 {
 	struct bpf_offload_dev *offdev;
 	int err;
@@ -688,6 +689,7 @@ bpf_offload_dev_create(const struct bpf_prog_offload_ops *ops)
 		return ERR_PTR(-ENOMEM);
 
 	offdev->ops = ops;
+	offdev->priv = priv;
 	INIT_LIST_HEAD(&offdev->netdevs);
 
 	return offdev;
@@ -700,3 +702,9 @@ void bpf_offload_dev_destroy(struct bpf_offload_dev *offdev)
 	kfree(offdev);
 }
 EXPORT_SYMBOL_GPL(bpf_offload_dev_destroy);
+
+void *bpf_offload_dev_priv(struct bpf_offload_dev *offdev)
+{
+	return offdev->priv;
+}
+EXPORT_SYMBOL_GPL(bpf_offload_dev_priv);
-- 
2.19.2

Re: [PATCH bpf-next] bpf: offload: add priv field for drivers

[Daniel Borkmann]

On 02/12/2019 09:20 AM, Jakub Kicinski wrote:
> Currently bpf_offload_dev does not have any priv pointer, forcing
> the drivers to work backwards from the netdev in program metadata.
> This is not great given programs are conceptually associated with
> the offload device, and it means one or two unnecessary deferences.
> Add a priv pointer to bpf_offload_dev.
> 
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>

Applied, thanks!