bpf: Reorder bpf_prog_test_run_skb initialization

This patch reorders the initialization of bpf_prog_test_run_skb to
simplify the subsequent patch. Program types are checked first, followed
by the ctx init, and finally the data init. With the subsequent patch,
program types and the ctx init provide information that is used in the
data init. Thus, we need the data init to happen last.

Signed-off-by: Paul Chaignon <[email protected]>
Signed-off-by: Martin KaFai Lau <[email protected]>
Link: https://patch.msgid.link/063475176f15828a882c07846017394baf72f682.1760037899.git.paul.chaignon@gmail.com

Author: pchaigno

net/bpf/test_run.c

@@ -993,19 +993,6 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 	if (size < ETH_HLEN)
 		return -EINVAL;
 
-	data = bpf_test_init(kattr, kattr->test.data_size_in,
-			     size, NET_SKB_PAD + NET_IP_ALIGN,
-			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
-	if (IS_ERR(data))
-		return PTR_ERR(data);
-
-	ctx = bpf_ctx_init(kattr, sizeof(struct __sk_buff));
-	if (IS_ERR(ctx)) {
-		ret = PTR_ERR(ctx);
-		ctx = NULL;
-		goto out;
-	}
-
 	switch (prog->type) {
 	case BPF_PROG_TYPE_SCHED_CLS:
 	case BPF_PROG_TYPE_SCHED_ACT:
@@ -1021,6 +1008,19 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 		break;
 	}
 
+	ctx = bpf_ctx_init(kattr, sizeof(struct __sk_buff));
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	data = bpf_test_init(kattr, kattr->test.data_size_in,
+			     size, NET_SKB_PAD + NET_IP_ALIGN,
+			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+	if (IS_ERR(data)) {
+		ret = PTR_ERR(data);
+		data = NULL;
+		goto out;
+	}
+
 	sk = sk_alloc(net, AF_UNSPEC, GFP_USER, &bpf_dummy_proto, 1);
 	if (!sk) {
 		ret = -ENOMEM;