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bpf: Compute bpf_skc_to_*() helper socket btf ids at build time 

Currently, socket types (struct tcp_sock, udp_sock, etc.)
used by bpf_skc_to_*() helpers are computed when vmlinux_btf
is first built in the kernel.

Commit 5a2798ab32
("bpf: Add BTF_ID_LIST/BTF_ID/BTF_ID_UNUSED macros")
implemented a mechanism to compute btf_ids at kernel build
time which can simplify kernel implementation and reduce
runtime overhead by removing in-kernel btf_id calculation.
This patch did exactly this, removing in-kernel btf_id
computation and utilizing build-time btf_id computation.

If CONFIG_DEBUG_INFO_BTF is not defined, BTF_ID_LIST will
define an array with size of 5, which is not enough for
btf_sock_ids. So define its own static array if
CONFIG_DEBUG_INFO_BTF is not defined.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720163358.1393023-1-yhs@fb.com
This commit is contained in:
Yonghong Song 2020-07-20 09:33:58 -07:00 committed by Alexei Starovoitov
parent e4d9c23207
commit bc4f0548f6
3 changed files with 18 additions and 36 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/bpf.h
View File

@ -1541,7 +1541,6 @@ static inline bool bpf_map_is_dev_bound(struct bpf_map *map)
struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr);
void bpf_map_offload_map_free(struct bpf_map *map);
void init_btf_sock_ids(struct btf *btf);
#else
static inline int bpf_prog_offload_init(struct bpf_prog *prog,
union bpf_attr *attr)
@ -1567,9 +1566,6 @@ static inline struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr)
static inline void bpf_map_offload_map_free(struct bpf_map *map)
{
}
static inline void init_btf_sock_ids(struct btf *btf)
{
}
#endif /* CONFIG_NET && CONFIG_BPF_SYSCALL */
#if defined(CONFIG_BPF_STREAM_PARSER)

1
kernel/bpf/btf.c
View File

@ -3672,7 +3672,6 @@ struct btf *btf_parse_vmlinux(void)
goto errout;
bpf_struct_ops_init(btf, log);
init_btf_sock_ids(btf);
btf_verifier_env_free(env);
refcount_set(&btf->refcnt, 1);

49
net/core/filter.c
View File

@ -9426,19 +9426,19 @@ void bpf_prog_change_xdp(struct bpf_prog *prev_prog, struct bpf_prog *prog)
* sock_common as the first argument in its memory layout.
*/
#define BTF_SOCK_TYPE_xxx \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, "inet_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, "inet_connection_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, "inet_request_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, "inet_timewait_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, "request_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, "sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, "sock_common") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, "tcp_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, "tcp_request_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, "tcp_timewait_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, "tcp6_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, "udp_sock") \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, "udp6_sock")
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET, inet_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_CONN, inet_connection_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_REQ, inet_request_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_INET_TW, inet_timewait_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_REQ, request_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK, sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_SOCK_COMMON, sock_common) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP, tcp_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_REQ, tcp_request_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP_TW, tcp_timewait_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_TCP6, tcp6_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP, udp_sock) \
BTF_SOCK_TYPE(BTF_SOCK_TYPE_UDP6, udp6_sock)
enum {
#define BTF_SOCK_TYPE(name, str) name,
@ -9447,26 +9447,13 @@ BTF_SOCK_TYPE_xxx
MAX_BTF_SOCK_TYPE,
};
static int btf_sock_ids[MAX_BTF_SOCK_TYPE];
#ifdef CONFIG_BPF_SYSCALL
static const char *bpf_sock_types[] = {
#define BTF_SOCK_TYPE(name, str) str,
#ifdef CONFIG_DEBUG_INFO_BTF
BTF_ID_LIST(btf_sock_ids)
#define BTF_SOCK_TYPE(name, type) BTF_ID(struct, type)
BTF_SOCK_TYPE_xxx
#undef BTF_SOCK_TYPE
};
void init_btf_sock_ids(struct btf *btf)
{
int i, btf_id;
for (i = 0; i < MAX_BTF_SOCK_TYPE; i++) {
btf_id = btf_find_by_name_kind(btf, bpf_sock_types[i],
BTF_KIND_STRUCT);
if (btf_id > 0)
btf_sock_ids[i] = btf_id;
}
}
#else
static u32 btf_sock_ids[MAX_BTF_SOCK_TYPE];
#endif
static bool check_arg_btf_id(u32 btf_id, u32 arg)