linux-kernel - [PATCH v2 bpf-next 1/3] bpf: pass struct btf pointer to the map_check

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Message-Id: <20181210234302.31327-2-guro@fb.com>
Date:   Mon, 10 Dec 2018 15:43:00 -0800
From:   Roman Gushchin <guroan@...il.com>
To:     netdev@...r.kernel.org
Cc:     kernel-team@...com, linux-kernel@...r.kernel.org,
        Yonghong Song <yhs@...com>, Martin Lau <kafai@...com>,
        Roman Gushchin <guro@...com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>
Subject: [PATCH v2 bpf-next 1/3] bpf: pass struct btf pointer to the map_check_btf() callback

If key_type or value_type are of non-trivial data types
(e.g. structure or typedef), it's not possible to check them without
the additional information, which can't be obtained without a pointer
to the btf structure.

So, let's pass btf pointer to the map_check_btf() callbacks.

Signed-off-by: Roman Gushchin <guro@...com>
Cc: Alexei Starovoitov <ast@...nel.org>
Cc: Daniel Borkmann <daniel@...earbox.net>
Acked-by: Martin KaFai Lau <kafai@...com>
---
 include/linux/bpf.h   | 3 +++
 kernel/bpf/arraymap.c | 1 +
 kernel/bpf/lpm_trie.c | 1 +
 kernel/bpf/syscall.c  | 3 ++-
 4 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 0c992b86eb2c..e734f163bd0b 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -23,6 +23,7 @@ struct bpf_prog;
 struct bpf_map;
 struct sock;
 struct seq_file;
+struct btf;
 struct btf_type;
 
 /* map is generic key/value storage optionally accesible by eBPF programs */
@@ -52,6 +53,7 @@ struct bpf_map_ops {
 	void (*map_seq_show_elem)(struct bpf_map *map, void *key,
 				  struct seq_file *m);
 	int (*map_check_btf)(const struct bpf_map *map,
+			     const struct btf *btf,
 			     const struct btf_type *key_type,
 			     const struct btf_type *value_type);
 };
@@ -126,6 +128,7 @@ static inline bool bpf_map_support_seq_show(const struct bpf_map *map)
 }
 
 int map_check_no_btf(const struct bpf_map *map,
+		     const struct btf *btf,
 		     const struct btf_type *key_type,
 		     const struct btf_type *value_type);
 
diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c
index 24583da9ffd1..25632a75d630 100644
--- a/kernel/bpf/arraymap.c
+++ b/kernel/bpf/arraymap.c
@@ -382,6 +382,7 @@ static void percpu_array_map_seq_show_elem(struct bpf_map *map, void *key,
 }
 
 static int array_map_check_btf(const struct bpf_map *map,
+			       const struct btf *btf,
 			       const struct btf_type *key_type,
 			       const struct btf_type *value_type)
 {
diff --git a/kernel/bpf/lpm_trie.c b/kernel/bpf/lpm_trie.c
index bfd4882e1106..abf1002080df 100644
--- a/kernel/bpf/lpm_trie.c
+++ b/kernel/bpf/lpm_trie.c
@@ -728,6 +728,7 @@ static int trie_get_next_key(struct bpf_map *map, void *_key, void *_next_key)
 }
 
 static int trie_check_btf(const struct bpf_map *map,
+			  const struct btf *btf,
 			  const struct btf_type *key_type,
 			  const struct btf_type *value_type)
 {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index a99a23bf5910..4eb7750cb5c0 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -456,6 +456,7 @@ static int bpf_obj_name_cpy(char *dst, const char *src)
 }
 
 int map_check_no_btf(const struct bpf_map *map,
+		     const struct btf *btf,
 		     const struct btf_type *key_type,
 		     const struct btf_type *value_type)
 {
@@ -478,7 +479,7 @@ static int map_check_btf(const struct bpf_map *map, const struct btf *btf,
 		return -EINVAL;
 
 	if (map->ops->map_check_btf)
-		ret = map->ops->map_check_btf(map, key_type, value_type);
+		ret = map->ops->map_check_btf(map, btf, key_type, value_type);
 
 	return ret;
 }
-- 
2.19.2