[PATCH net 2/2] nfp: bpf: keep track of the offloaded program

[Jakub Kicinski <jakub.kicinski@netronome.com>]

After TC offloads were converted to callbacks we have no choice
but keep track of the offloaded filter in the driver.

The check for nn->dp.bpf_offload_xdp was a stop gap solution
to make sure failed TC offload won't disable XDP, it's no longer
necessary.  nfp_net_bpf_offload() will return -EBUSY on
TC vs XDP conflicts.

Fixes: 3f7889c4c79b ("net: sched: cls_bpf: call block callbacks for offload")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
---
Dave, this will conflict on nfp_bpf_vnic_free() with net-next.
The function was removed since stack will stop XDP now, but
we need to add it back with just the WARN and free on @bv.
---
 drivers/net/ethernet/netronome/nfp/bpf/main.c | 47 ++++++++++++++++++++++++---
 drivers/net/ethernet/netronome/nfp/bpf/main.h |  8 +++++
 2 files changed, 51 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.c b/drivers/net/ethernet/netronome/nfp/bpf/main.c
index a4cf62ba4604..13190aa09faf 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.c
+++ b/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 ||
@@ -113,7 +137,22 @@ static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type type,
 	if (cls_bpf->command != TC_CLSBPF_OFFLOAD)
 		return -EOPNOTSUPP;
 
-	return nfp_net_bpf_offload(nn, cls_bpf->prog, cls_bpf->oldprog);
+	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,
@@ -161,7 +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,
diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.h b/drivers/net/ethernet/netronome/nfp/bpf/main.h
index 082a15f6dfb5..57b6043177a3 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.h
+++ b/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;
-- 
2.15.1