LoongArch: BPF: Make error handling robust in arch_prepare_bpf_trampoline()

Bail out instead of trying to perform a bpf_arch_text_copy() if
__arch_prepare_bpf_trampoline() failed.

Cc: stable@vger.kernel.org
Tested-by: Vincent Li <vincent.mc.li@gmail.com>
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: chenhengqi

arch/loongarch/net/bpf_jit.c

@@ -1715,7 +1715,10 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *ro_image,
 
 	jit_fill_hole(image, (unsigned int)(ro_image_end - ro_image));
 	ret = __arch_prepare_bpf_trampoline(&ctx, im, m, tlinks, func_addr, flags);
-	if (ret > 0 && validate_code(&ctx) < 0) {
+	if (ret < 0)
+		goto out;
+
+	if (validate_code(&ctx) < 0) {
 		ret = -EINVAL;
 		goto out;
 	}