tools/testing/selftests/bpf/progs/local_kptr_stash.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/bpf/progs/local_kptr_stash.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/bpf/progs/local_kptr_stash.c
Extension
.c
Size
5686 bytes
Lines
286
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct node_data {
	long key;
	long data;
	struct plain_local __kptr * stashed_in_local_kptr;
	struct bpf_rb_node node;
};

struct refcounted_node {
	long data;
	struct bpf_rb_node rb_node;
	struct bpf_refcount refcount;
};

struct stash {
	struct bpf_spin_lock l;
	struct refcounted_node __kptr *stashed;
};

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__type(key, int);
	__type(value, struct stash);
	__uint(max_entries, 10);
} refcounted_node_stash SEC(".maps");

struct plain_local {
	long key;
	long data;
};

struct local_with_root {
	long key;
	struct bpf_spin_lock l;
	struct bpf_rb_root r __contains(node_data, node);
};

struct map_value {
	struct prog_test_ref_kfunc *not_kptr;
	struct prog_test_ref_kfunc __kptr *val;
	struct node_data __kptr *node;
	struct plain_local __kptr *plain;
	struct local_with_root __kptr *local_root;
};

/* This is necessary so that LLVM generates BTF for node_data struct
 * If it's not included, a fwd reference for node_data will be generated but
 * no struct. Example BTF of "node" field in map_value when not included:
 *
 * [10] PTR '(anon)' type_id=35
 * [34] FWD 'node_data' fwd_kind=struct
 * [35] TYPE_TAG 'kptr_ref' type_id=34
 *
 * (with no node_data struct defined)
 * Had to do the same w/ bpf_kfunc_call_test_release below
 */
struct node_data *just_here_because_btf_bug;
struct refcounted_node *just_here_because_btf_bug2;

struct {
	__uint(type, BPF_MAP_TYPE_ARRAY);
	__type(key, int);
	__type(value, struct map_value);
	__uint(max_entries, 2);
} some_nodes SEC(".maps");

static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)
{
	struct node_data *node_a;
	struct node_data *node_b;

	node_a = container_of(a, struct node_data, node);
	node_b = container_of(b, struct node_data, node);

	return node_a->key < node_b->key;
}

static int create_and_stash(int idx, int val)
{
	struct plain_local *inner_local_kptr;
	struct map_value *mapval;
	struct node_data *res;

	mapval = bpf_map_lookup_elem(&some_nodes, &idx);
	if (!mapval)
		return 1;

	inner_local_kptr = bpf_obj_new(typeof(*inner_local_kptr));
	if (!inner_local_kptr)
		return 2;

Annotation

Implementation Notes