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Date: Tue, 4 Apr 2017 19:27:10 +0200
From: Johannes Berg <johannes@...solutions.net>
To: netdev@...r.kernel.org
Cc: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Johannes Berg <johannes.berg@...el.com>
Subject: [PATCH 1/2] bpf: remove struct bpf_prog_type_list
From: Johannes Berg <johannes.berg@...el.com>
There's no need to have struct bpf_prog_type_list since
it just contains a list_head, the type, and the ops
pointer. Since the types are densely packed and not
actually dynamically registered, it's much easier and
smaller to have an array of type->ops pointer.
This doesn't really change the image size much, but in
the running image it saves a few hundred bytes because
the structs are removed and traded against __init code.
While at it, also mark bpf_register_prog_type() __init
since it's only called from code already marked so.
Signed-off-by: Johannes Berg <johannes.berg@...el.com>
---
So I'm not sure about this - I looked at this code since
I wanted to see if we could even register prog_types from
modules, but that seems to be impossible right now ...
---
include/linux/bpf.h | 12 +++------
include/uapi/linux/bpf.h | 2 ++
kernel/bpf/syscall.c | 26 ++++++++++----------
kernel/trace/bpf_trace.c | 21 +++-------------
net/core/filter.c | 63 +++++++-----------------------------------------
5 files changed, 31 insertions(+), 93 deletions(-)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 909fc033173a..891a76aaccaa 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -169,12 +169,6 @@ struct bpf_verifier_ops {
struct bpf_prog *prog);
};
-struct bpf_prog_type_list {
- struct list_head list_node;
- const struct bpf_verifier_ops *ops;
- enum bpf_prog_type type;
-};
-
struct bpf_prog_aux {
atomic_t refcnt;
u32 used_map_cnt;
@@ -234,7 +228,8 @@ u64 bpf_event_output(struct bpf_map *map, u64 flags, void *meta, u64 meta_size,
#ifdef CONFIG_BPF_SYSCALL
DECLARE_PER_CPU(int, bpf_prog_active);
-void bpf_register_prog_type(struct bpf_prog_type_list *tl);
+void bpf_register_prog_type(enum bpf_prog_type type,
+ const struct bpf_verifier_ops *ops);
void bpf_register_map_type(struct bpf_map_type_list *tl);
struct bpf_prog *bpf_prog_get(u32 ufd);
@@ -295,7 +290,8 @@ static inline void bpf_long_memcpy(void *dst, const void *src, u32 size)
/* verify correctness of eBPF program */
int bpf_check(struct bpf_prog **fp, union bpf_attr *attr);
#else
-static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
+static inline void bpf_register_prog_type(enum bpf_prog_type type,
+ const struct bpf_verifier_ops *ops)
{
}
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0539a0ceef38..cc68f5bbf458 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -112,6 +112,8 @@ enum bpf_prog_type {
BPF_PROG_TYPE_LWT_IN,
BPF_PROG_TYPE_LWT_OUT,
BPF_PROG_TYPE_LWT_XMIT,
+
+ NUM_BPF_PROG_TYPES,
};
enum bpf_attach_type {
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 7af0dcc5d755..1156eccf36a5 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -564,26 +564,26 @@ static int map_get_next_key(union bpf_attr *attr)
return err;
}
-static LIST_HEAD(bpf_prog_types);
+static const struct bpf_verifier_ops *
+bpf_prog_types[NUM_BPF_PROG_TYPES] __ro_after_init;
static int find_prog_type(enum bpf_prog_type type, struct bpf_prog *prog)
{
- struct bpf_prog_type_list *tl;
-
- list_for_each_entry(tl, &bpf_prog_types, list_node) {
- if (tl->type == type) {
- prog->aux->ops = tl->ops;
- prog->type = type;
- return 0;
- }
- }
+ if (type >= NUM_BPF_PROG_TYPES || !bpf_prog_types[type])
+ return -EINVAL;
- return -EINVAL;
+ prog->aux->ops = bpf_prog_types[type];
+ prog->type = type;
+ return 0;
}
-void bpf_register_prog_type(struct bpf_prog_type_list *tl)
+void __init bpf_register_prog_type(enum bpf_prog_type type,
+ const struct bpf_verifier_ops *ops)
{
- list_add(&tl->list_node, &bpf_prog_types);
+ if (WARN_ON(bpf_prog_types[type]))
+ return;
+
+ bpf_prog_types[type] = ops;
}
/* fixup insn->imm field of bpf_call instructions:
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index cee9802cf3e0..1e45e1cd0174 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -506,11 +506,6 @@ static const struct bpf_verifier_ops kprobe_prog_ops = {
.is_valid_access = kprobe_prog_is_valid_access,
};
-static struct bpf_prog_type_list kprobe_tl __ro_after_init = {
- .ops = &kprobe_prog_ops,
- .type = BPF_PROG_TYPE_KPROBE,
-};
-
BPF_CALL_5(bpf_perf_event_output_tp, void *, tp_buff, struct bpf_map *, map,
u64, flags, void *, data, u64, size)
{
@@ -589,11 +584,6 @@ static const struct bpf_verifier_ops tracepoint_prog_ops = {
.is_valid_access = tp_prog_is_valid_access,
};
-static struct bpf_prog_type_list tracepoint_tl __ro_after_init = {
- .ops = &tracepoint_prog_ops,
- .type = BPF_PROG_TYPE_TRACEPOINT,
-};
-
static bool pe_prog_is_valid_access(int off, int size, enum bpf_access_type type,
enum bpf_reg_type *reg_type)
{
@@ -648,16 +638,11 @@ static const struct bpf_verifier_ops perf_event_prog_ops = {
.convert_ctx_access = pe_prog_convert_ctx_access,
};
-static struct bpf_prog_type_list perf_event_tl __ro_after_init = {
- .ops = &perf_event_prog_ops,
- .type = BPF_PROG_TYPE_PERF_EVENT,
-};
-
static int __init register_kprobe_prog_ops(void)
{
- bpf_register_prog_type(&kprobe_tl);
- bpf_register_prog_type(&tracepoint_tl);
- bpf_register_prog_type(&perf_event_tl);
+ bpf_register_prog_type(BPF_PROG_TYPE_KPROBE, &kprobe_prog_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_TRACEPOINT, &tracepoint_prog_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_PERF_EVENT, &perf_event_prog_ops);
return 0;
}
late_initcall(register_kprobe_prog_ops);
diff --git a/net/core/filter.c b/net/core/filter.c
index ebaeaf2e46e8..d5218c891d43 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -3296,62 +3296,17 @@ static const struct bpf_verifier_ops cg_sock_ops = {
.convert_ctx_access = sock_filter_convert_ctx_access,
};
-static struct bpf_prog_type_list sk_filter_type __ro_after_init = {
- .ops = &sk_filter_ops,
- .type = BPF_PROG_TYPE_SOCKET_FILTER,
-};
-
-static struct bpf_prog_type_list sched_cls_type __ro_after_init = {
- .ops = &tc_cls_act_ops,
- .type = BPF_PROG_TYPE_SCHED_CLS,
-};
-
-static struct bpf_prog_type_list sched_act_type __ro_after_init = {
- .ops = &tc_cls_act_ops,
- .type = BPF_PROG_TYPE_SCHED_ACT,
-};
-
-static struct bpf_prog_type_list xdp_type __ro_after_init = {
- .ops = &xdp_ops,
- .type = BPF_PROG_TYPE_XDP,
-};
-
-static struct bpf_prog_type_list cg_skb_type __ro_after_init = {
- .ops = &cg_skb_ops,
- .type = BPF_PROG_TYPE_CGROUP_SKB,
-};
-
-static struct bpf_prog_type_list lwt_in_type __ro_after_init = {
- .ops = &lwt_inout_ops,
- .type = BPF_PROG_TYPE_LWT_IN,
-};
-
-static struct bpf_prog_type_list lwt_out_type __ro_after_init = {
- .ops = &lwt_inout_ops,
- .type = BPF_PROG_TYPE_LWT_OUT,
-};
-
-static struct bpf_prog_type_list lwt_xmit_type __ro_after_init = {
- .ops = &lwt_xmit_ops,
- .type = BPF_PROG_TYPE_LWT_XMIT,
-};
-
-static struct bpf_prog_type_list cg_sock_type __ro_after_init = {
- .ops = &cg_sock_ops,
- .type = BPF_PROG_TYPE_CGROUP_SOCK
-};
-
static int __init register_sk_filter_ops(void)
{
- bpf_register_prog_type(&sk_filter_type);
- bpf_register_prog_type(&sched_cls_type);
- bpf_register_prog_type(&sched_act_type);
- bpf_register_prog_type(&xdp_type);
- bpf_register_prog_type(&cg_skb_type);
- bpf_register_prog_type(&cg_sock_type);
- bpf_register_prog_type(&lwt_in_type);
- bpf_register_prog_type(&lwt_out_type);
- bpf_register_prog_type(&lwt_xmit_type);
+ bpf_register_prog_type(BPF_PROG_TYPE_SOCKET_FILTER, &sk_filter_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_SCHED_CLS, &tc_cls_act_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_SCHED_ACT, &tc_cls_act_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_XDP, &xdp_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_CGROUP_SKB, &cg_skb_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_CGROUP_SOCK, &cg_sock_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_LWT_IN, &lwt_inout_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_LWT_OUT, &lwt_inout_ops);
+ bpf_register_prog_type(BPF_PROG_TYPE_LWT_XMIT, &lwt_xmit_ops);
return 0;
}
--
2.11.0
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