[patch net-next v2 01/10] cls_bpf: move prog offload->netdev check into drivers

[Jiri Pirko <jiri@resnulli.us>]

From: Jiri Pirko <jiri@mellanox.com>

In order to remove tp->q usage in cls_bpf, the offload->netdev check
needs to be moved to individual drivers as only they will have access
to appropriate struct net_device.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/main.c |  2 ++
 include/linux/bpf.h                           | 16 +++++++++++
 kernel/bpf/syscall.c                          | 39 +++++++++++++++++++++------
 net/sched/cls_bpf.c                           |  6 +----
 4 files changed, 50 insertions(+), 13 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/main.c b/drivers/net/ethernet/netronome/nfp/bpf/main.c
index e379b78..c303e08 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/main.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/main.c
@@ -102,6 +102,8 @@ static int nfp_bpf_setup_tc_block_cb(enum tc_setup_type type,
 		return -EOPNOTSUPP;
 	if (nn->dp.bpf_offload_xdp)
 		return -EBUSY;
+	if (!bpf_prog_can_attach_netdev(cls_bpf->prog, nn->dp.netdev))
+		return -EINVAL;
 
 	/* Only support TC direct action */
 	if (!cls_bpf->exts_integrated ||
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index c397934..df7b7bc 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -337,10 +337,14 @@ struct bpf_prog *bpf_prog_get(u32 ufd);
 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type);
 struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
 				       struct net_device *netdev);
+struct bpf_prog *bpf_prog_get_type_dev_nocheck(u32 ufd,
+					       enum bpf_prog_type type);
 struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog, int i);
 void bpf_prog_sub(struct bpf_prog *prog, int i);
 struct bpf_prog * __must_check bpf_prog_inc(struct bpf_prog *prog);
 struct bpf_prog * __must_check bpf_prog_inc_not_zero(struct bpf_prog *prog);
+bool bpf_prog_can_attach_netdev(struct bpf_prog *prog,
+				struct net_device *netdev);
 void bpf_prog_put(struct bpf_prog *prog);
 int __bpf_prog_charge(struct user_struct *user, u32 pages);
 void __bpf_prog_uncharge(struct user_struct *user, u32 pages);
@@ -438,6 +442,12 @@ static inline struct bpf_prog *bpf_prog_get_type_dev(u32 ufd,
 	return ERR_PTR(-EOPNOTSUPP);
 }
 
+static inline struct bpf_prog *
+bpf_prog_get_type_dev_nocheck(u32 ufd, enum bpf_prog_type type)
+{
+	return ERR_PTR(-EOPNOTSUPP);
+}
+
 static inline struct bpf_prog * __must_check bpf_prog_add(struct bpf_prog *prog,
 							  int i)
 {
@@ -463,6 +473,12 @@ bpf_prog_inc_not_zero(struct bpf_prog *prog)
 	return ERR_PTR(-EOPNOTSUPP);
 }
 
+static inline bool bpf_prog_can_attach_netdev(struct bpf_prog *prog,
+					      struct net_device *netdev)
+{
+	return true;
+}
+
 static inline int __bpf_prog_charge(struct user_struct *user, u32 pages)
 {
 	return 0;
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 09badc3..d880038 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -1057,22 +1057,33 @@ struct bpf_prog *bpf_prog_inc_not_zero(struct bpf_prog *prog)
 }
 EXPORT_SYMBOL_GPL(bpf_prog_inc_not_zero);
 
-static bool bpf_prog_can_attach(struct bpf_prog *prog,
-				enum bpf_prog_type *attach_type,
+bool bpf_prog_can_attach_netdev(struct bpf_prog *prog,
 				struct net_device *netdev)
 {
 	struct bpf_dev_offload *offload = prog->aux->offload;
 
+	if (offload && offload->netdev != netdev)
+		return false;
+
+	return true;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_can_attach_netdev);
+
+static bool bpf_prog_can_attach(struct bpf_prog *prog,
+				enum bpf_prog_type *attach_type,
+				struct net_device *netdev, bool check_netdev)
+{
 	if (prog->type != *attach_type)
 		return false;
-	if (offload && offload->netdev != netdev)
+	if (check_netdev && !bpf_prog_can_attach_netdev(prog, netdev))
 		return false;
 
 	return true;
 }
 
 static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
-				       struct net_device *netdev)
+				       struct net_device *netdev,
+				       bool check_netdev)
 {
 	struct fd f = fdget(ufd);
 	struct bpf_prog *prog;
@@ -1080,7 +1091,8 @@ static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
 	prog = ____bpf_prog_get(f);
 	if (IS_ERR(prog))
 		return prog;
-	if (attach_type && !bpf_prog_can_attach(prog, attach_type, netdev)) {
+	if (attach_type && !bpf_prog_can_attach(prog, attach_type,
+						netdev, check_netdev)) {
 		prog = ERR_PTR(-EINVAL);
 		goto out;
 	}
@@ -1093,12 +1105,12 @@ static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
 
 struct bpf_prog *bpf_prog_get(u32 ufd)
 {
-	return __bpf_prog_get(ufd, NULL, NULL);
+	return __bpf_prog_get(ufd, NULL, NULL, true);
 }
 
 struct bpf_prog *bpf_prog_get_type(u32 ufd, enum bpf_prog_type type)
 {
-	struct bpf_prog *prog = __bpf_prog_get(ufd, &type, NULL);
+	struct bpf_prog *prog = __bpf_prog_get(ufd, &type, NULL, true);
 
 	if (!IS_ERR(prog))
 		trace_bpf_prog_get_type(prog);
@@ -1109,7 +1121,7 @@ EXPORT_SYMBOL_GPL(bpf_prog_get_type);
 struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
 				       struct net_device *netdev)
 {
-	struct bpf_prog *prog = __bpf_prog_get(ufd, &type, netdev);
+	struct bpf_prog *prog = __bpf_prog_get(ufd, &type, netdev, true);
 
 	if (!IS_ERR(prog))
 		trace_bpf_prog_get_type(prog);
@@ -1117,6 +1129,17 @@ struct bpf_prog *bpf_prog_get_type_dev(u32 ufd, enum bpf_prog_type type,
 }
 EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev);
 
+struct bpf_prog *bpf_prog_get_type_dev_nocheck(u32 ufd,
+					       enum bpf_prog_type type)
+{
+	struct bpf_prog *prog = __bpf_prog_get(ufd, &type, NULL, false);
+
+	if (!IS_ERR(prog))
+		trace_bpf_prog_get_type(prog);
+	return prog;
+}
+EXPORT_SYMBOL_GPL(bpf_prog_get_type_dev_nocheck);
+
 /* last field in 'union bpf_attr' used by this command */
 #define	BPF_PROG_LOAD_LAST_FIELD prog_target_ifindex
 
diff --git a/net/sched/cls_bpf.c b/net/sched/cls_bpf.c
index fb680da..8b3927b 100644
--- a/net/sched/cls_bpf.c
+++ b/net/sched/cls_bpf.c
@@ -386,11 +386,7 @@ static int cls_bpf_prog_from_efd(struct nlattr **tb, struct cls_bpf_prog *prog,
 
 	bpf_fd = nla_get_u32(tb[TCA_BPF_FD]);
 
-	if (gen_flags & TCA_CLS_FLAGS_SKIP_SW)
-		fp = bpf_prog_get_type_dev(bpf_fd, BPF_PROG_TYPE_SCHED_CLS,
-					   qdisc_dev(tp->q));
-	else
-		fp = bpf_prog_get_type(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
+	fp = bpf_prog_get_type_dev_nocheck(bpf_fd, BPF_PROG_TYPE_SCHED_CLS);
 	if (IS_ERR(fp))
 		return PTR_ERR(fp);
 
-- 
2.9.5