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

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Date:   Tue, 19 Dec 2017 13:32:14 -0800
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     netdev@...r.kernel.org
Cc:     daniel@...earbox.net, jiri@...nulli.us, oss-drivers@...ronome.com,
        Jakub Kicinski <jakub.kicinski@...ronome.com>
Subject: [PATCH net 2/2] nfp: bpf: keep track of the offloaded program

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@...ronome.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