Commit 951cf368 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: net: Use precomputed btf_id for bpf iterators 



One additional field btf_id is added to struct
bpf_ctx_arg_aux to store the precomputed btf_ids.
The btf_id is computed at build time with
BTF_ID_LIST or BTF_ID_LIST_GLOBAL macro definitions.
All existing bpf iterators are changed to used
pre-compute btf_ids.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200720163403.1393551-1-yhs@fb.com
parent fce557bc

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -668,6 +668,7 @@ struct bpf_jit_poke_descriptor { 
struct bpf_ctx_arg_aux {

	u32 offset;

	enum bpf_reg_type reg_type;

	u32 btf_id;

};



struct bpf_prog_aux {

kernel/bpf/btf.c

+3 −2
Original line number Diff line number Diff line
@@ -3817,16 +3817,17 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, 
		return true;



	/* this is a pointer to another type */

	info->reg_type = PTR_TO_BTF_ID;

	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {

		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];



		if (ctx_arg_info->offset == off) {

			info->reg_type = ctx_arg_info->reg_type;

			break;

			info->btf_id = ctx_arg_info->btf_id;

			return true;

		}

	}



	info->reg_type = PTR_TO_BTF_ID;

	if (tgt_prog) {

		ret = btf_translate_to_vmlinux(log, btf, t, tgt_prog->type, arg);

		if (ret > 0) {

kernel/bpf/map_iter.c

+6 −1
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 
#include <linux/fs.h>

#include <linux/filter.h>

#include <linux/kernel.h>

#include <linux/btf_ids.h>



struct bpf_iter_seq_map_info {

	u32 mid;
@@ -81,7 +82,10 @@ static const struct seq_operations bpf_map_seq_ops = { 
	.show	= bpf_map_seq_show,

};



static const struct bpf_iter_reg bpf_map_reg_info = {

BTF_ID_LIST(btf_bpf_map_id)

BTF_ID(struct, bpf_map)



static struct bpf_iter_reg bpf_map_reg_info = {

	.target			= "bpf_map",

	.seq_ops		= &bpf_map_seq_ops,

	.init_seq_private	= NULL,
@@ -96,6 +100,7 @@ static const struct bpf_iter_reg bpf_map_reg_info = { 


static int __init bpf_map_iter_init(void)

{

	bpf_map_reg_info.ctx_arg_info[0].btf_id = *btf_bpf_map_id;

	return bpf_iter_reg_target(&bpf_map_reg_info);

}

kernel/bpf/task_iter.c

+10 −2
Original line number Diff line number Diff line
@@ -7,6 +7,7 @@ 
#include <linux/fs.h>

#include <linux/fdtable.h>

#include <linux/filter.h>

#include <linux/btf_ids.h>



struct bpf_iter_seq_task_common {

	struct pid_namespace *ns;
@@ -312,7 +313,11 @@ static const struct seq_operations task_file_seq_ops = { 
	.show	= task_file_seq_show,

};



static const struct bpf_iter_reg task_reg_info = {

BTF_ID_LIST(btf_task_file_ids)

BTF_ID(struct, task_struct)

BTF_ID(struct, file)



static struct bpf_iter_reg task_reg_info = {

	.target			= "task",

	.seq_ops		= &task_seq_ops,

	.init_seq_private	= init_seq_pidns,
@@ -325,7 +330,7 @@ static const struct bpf_iter_reg task_reg_info = { 
	},

};



static const struct bpf_iter_reg task_file_reg_info = {

static struct bpf_iter_reg task_file_reg_info = {

	.target			= "task_file",

	.seq_ops		= &task_file_seq_ops,

	.init_seq_private	= init_seq_pidns,
@@ -344,10 +349,13 @@ static int __init task_iter_init(void) 
{

	int ret;



	task_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];

	ret = bpf_iter_reg_target(&task_reg_info);

	if (ret)

		return ret;



	task_file_reg_info.ctx_arg_info[0].btf_id = btf_task_file_ids[0];

	task_file_reg_info.ctx_arg_info[1].btf_id = btf_task_file_ids[1];

	return bpf_iter_reg_target(&task_file_reg_info);

}

late_initcall(task_iter_init);

net/ipv4/tcp_ipv4.c

+3 −1
Original line number Diff line number Diff line
@@ -76,6 +76,7 @@ 
#include <linux/proc_fs.h>

#include <linux/seq_file.h>

#include <linux/inetdevice.h>

#include <linux/btf_ids.h>



#include <crypto/hash.h>

#include <linux/scatterlist.h>
@@ -2954,7 +2955,7 @@ static void bpf_iter_fini_tcp(void *priv_data) 
	bpf_iter_fini_seq_net(priv_data);

}



static const struct bpf_iter_reg tcp_reg_info = {

static struct bpf_iter_reg tcp_reg_info = {

	.target			= "tcp",

	.seq_ops		= &bpf_iter_tcp_seq_ops,

	.init_seq_private	= bpf_iter_init_tcp,
@@ -2969,6 +2970,7 @@ static const struct bpf_iter_reg tcp_reg_info = { 


static void __init bpf_iter_register(void)

{

	tcp_reg_info.ctx_arg_info[0].btf_id = btf_sock_ids[BTF_SOCK_TYPE_SOCK_COMMON];

	if (bpf_iter_reg_target(&tcp_reg_info))

		pr_warn("Warning: could not register bpf iterator tcp\n");

}