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

File Facts

System

Linux kernel

Corpus path

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

Extension

.c

Size

767 bytes

Lines

37

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.

• Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/bpf.h
• bpf/bpf_helpers.h
• bpf/bpf_tracing.h

Detected Declarations

• struct val
• function bpf_obj_cancel_fields

Annotated Snippet

struct val {
	struct bpf_timer t;
	__u64 payload;
};

struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(max_entries, 1);
	__type(key, __u32);
	__type(value, struct val);
} htab SEC(".maps");

int pid = 0;
int update_err = 0;

SEC("?fentry/bpf_obj_cancel_fields")
int bpf_obj_cancel_fields(void *ctx)
{
	__u32 key = 0;
	struct val value = { .payload = 1 };

	if ((bpf_get_current_pid_tgid() >> 32) != pid)
		return 0;

	update_err = bpf_map_update_elem(&htab, &key, &value, BPF_ANY);
	return 0;
}

Annotation

• Immediate include surface: `linux/bpf.h`, `bpf/bpf_helpers.h`, `bpf/bpf_tracing.h`.
• Detected declarations: `struct val`, `function bpf_obj_cancel_fields`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.