Commit 15172a46 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

bpf: net: Refactor bpf_iter target registration 



Currently bpf_iter_reg_target takes parameters from target
and allocates memory to save them. This is really not
necessary, esp. in the future we may grow information
passed from targets to bpf_iter manager.

The patch refactors the code so target reg_info
becomes static and bpf_iter manager can just take
a reference to it.

Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200513180219.2949605-1-yhs@fb.com
parent 2e3ed68b

include/linux/bpf.h

+1 −1
Original line number Diff line number Diff line
@@ -1153,7 +1153,7 @@ struct bpf_iter_meta { 
	u64 seq_num;

};



int bpf_iter_reg_target(struct bpf_iter_reg *reg_info);

int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info);

void bpf_iter_unreg_target(const char *target);

bool bpf_iter_prog_supported(struct bpf_prog *prog);

int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog);

kernel/bpf/bpf_iter.c

+17 −19
Original line number Diff line number Diff line
@@ -8,11 +8,7 @@ 


struct bpf_iter_target_info {

	struct list_head list;

	const char *target;

	const struct seq_operations *seq_ops;

	bpf_iter_init_seq_priv_t init_seq_private;

	bpf_iter_fini_seq_priv_t fini_seq_private;

	u32 seq_priv_size;

	const struct bpf_iter_reg *reg_info;

	u32 btf_id;	/* cached value */

};
@@ -222,8 +218,8 @@ static int iter_release(struct inode *inode, struct file *file) 
	iter_priv = container_of(seq->private, struct bpf_iter_priv_data,

				 target_private);



	if (iter_priv->tinfo->fini_seq_private)

		iter_priv->tinfo->fini_seq_private(seq->private);

	if (iter_priv->tinfo->reg_info->fini_seq_private)

		iter_priv->tinfo->reg_info->fini_seq_private(seq->private);



	bpf_prog_put(iter_priv->prog);

	seq->private = iter_priv;
@@ -238,7 +234,12 @@ const struct file_operations bpf_iter_fops = { 
	.release	= iter_release,

};



int bpf_iter_reg_target(struct bpf_iter_reg *reg_info)

/* The argument reg_info will be cached in bpf_iter_target_info.

 * The common practice is to declare target reg_info as

 * a const static variable and passed as an argument to

 * bpf_iter_reg_target().

 */

int bpf_iter_reg_target(const struct bpf_iter_reg *reg_info)

{

	struct bpf_iter_target_info *tinfo;
@@ -246,11 +247,7 @@ int bpf_iter_reg_target(struct bpf_iter_reg *reg_info) 
	if (!tinfo)

		return -ENOMEM;



	tinfo->target = reg_info->target;

	tinfo->seq_ops = reg_info->seq_ops;

	tinfo->init_seq_private = reg_info->init_seq_private;

	tinfo->fini_seq_private = reg_info->fini_seq_private;

	tinfo->seq_priv_size = reg_info->seq_priv_size;

	tinfo->reg_info = reg_info;

	INIT_LIST_HEAD(&tinfo->list);



	mutex_lock(&targets_mutex);
@@ -267,7 +264,7 @@ void bpf_iter_unreg_target(const char *target) 


	mutex_lock(&targets_mutex);

	list_for_each_entry(tinfo, &targets, list) {

		if (!strcmp(target, tinfo->target)) {

		if (!strcmp(target, tinfo->reg_info->target)) {

			list_del(&tinfo->list);

			kfree(tinfo);

			found = true;
@@ -303,7 +300,7 @@ bool bpf_iter_prog_supported(struct bpf_prog *prog) 
			supported = true;

			break;

		}

		if (!strcmp(attach_fname + prefix_len, tinfo->target)) {

		if (!strcmp(attach_fname + prefix_len, tinfo->reg_info->target)) {

			cache_btf_id(tinfo, prog);

			supported = true;

			break;
@@ -431,15 +428,16 @@ static int prepare_seq_file(struct file *file, struct bpf_iter_link *link) 


	tinfo = link->tinfo;

	total_priv_dsize = offsetof(struct bpf_iter_priv_data, target_private) +

			   tinfo->seq_priv_size;

	priv_data = __seq_open_private(file, tinfo->seq_ops, total_priv_dsize);

			   tinfo->reg_info->seq_priv_size;

	priv_data = __seq_open_private(file, tinfo->reg_info->seq_ops,

				       total_priv_dsize);

	if (!priv_data) {

		err = -ENOMEM;

		goto release_prog;

	}



	if (tinfo->init_seq_private) {

		err = tinfo->init_seq_private(priv_data->target_private);

	if (tinfo->reg_info->init_seq_private) {

		err = tinfo->reg_info->init_seq_private(priv_data->target_private);

		if (err)

			goto release_seq_file;

	}

kernel/bpf/map_iter.c

+9 −9
Original line number Diff line number Diff line
@@ -81,9 +81,7 @@ static const struct seq_operations bpf_map_seq_ops = { 
	.show	= bpf_map_seq_show,

};



static int __init bpf_map_iter_init(void)

{

	struct bpf_iter_reg reg_info = {

static const struct bpf_iter_reg bpf_map_reg_info = {

	.target			= "bpf_map",

	.seq_ops		= &bpf_map_seq_ops,

	.init_seq_private	= NULL,
@@ -91,7 +89,9 @@ static int __init bpf_map_iter_init(void) 
	.seq_priv_size		= sizeof(struct bpf_iter_seq_map_info),

};



	return bpf_iter_reg_target(&reg_info);

static int __init bpf_map_iter_init(void)

{

	return bpf_iter_reg_target(&bpf_map_reg_info);

}



late_initcall(bpf_map_iter_init);

kernel/bpf/task_iter.c

+16 −14
Original line number Diff line number Diff line
@@ -306,22 +306,24 @@ static const struct seq_operations task_file_seq_ops = { 
	.show	= task_file_seq_show,

};



static int __init task_iter_init(void)

{

	struct bpf_iter_reg task_file_reg_info = {

		.target			= "task_file",

		.seq_ops		= &task_file_seq_ops,

		.init_seq_private	= init_seq_pidns,

		.fini_seq_private	= fini_seq_pidns,

		.seq_priv_size		= sizeof(struct bpf_iter_seq_task_file_info),

	};

	struct bpf_iter_reg task_reg_info = {

static const struct bpf_iter_reg task_reg_info = {

	.target			= "task",

	.seq_ops		= &task_seq_ops,

	.init_seq_private	= init_seq_pidns,

	.fini_seq_private	= fini_seq_pidns,

	.seq_priv_size		= sizeof(struct bpf_iter_seq_task_info),

};



static const struct bpf_iter_reg task_file_reg_info = {

	.target			= "task_file",

	.seq_ops		= &task_file_seq_ops,

	.init_seq_private	= init_seq_pidns,

	.fini_seq_private	= fini_seq_pidns,

	.seq_priv_size		= sizeof(struct bpf_iter_seq_task_file_info),

};



static int __init task_iter_init(void)

{

	int ret;



	ret = bpf_iter_reg_target(&task_reg_info);

net/ipv6/route.c

+9 −9
Original line number Diff line number Diff line
@@ -6397,9 +6397,7 @@ void __init ip6_route_init_special_entries(void) 
#if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_PROC_FS)

DEFINE_BPF_ITER_FUNC(ipv6_route, struct bpf_iter_meta *meta, struct fib6_info *rt)



static int __init bpf_iter_register(void)

{

	struct bpf_iter_reg reg_info = {

static const struct bpf_iter_reg ipv6_route_reg_info = {

	.target			= "ipv6_route",

	.seq_ops		= &ipv6_route_seq_ops,

	.init_seq_private	= bpf_iter_init_seq_net,
@@ -6407,7 +6405,9 @@ static int __init bpf_iter_register(void) 
	.seq_priv_size		= sizeof(struct ipv6_route_iter),

};



	return bpf_iter_reg_target(&reg_info);

static int __init bpf_iter_register(void)

{

	return bpf_iter_reg_target(&ipv6_route_reg_info);

}



static void bpf_iter_unregister(void)

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