tools/include/linux/refcount.h

File Facts

System

Linux kernel

Corpus path

tools/include/linux/refcount.h

Extension

.h

Size

4309 bytes

Lines

158

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.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/atomic.h
• linux/kernel.h

Detected Declarations

• function refcount_set
• function refcount_set_release
• function refcount_read
• function atomic_inc_not_zero
• function atomic_inc
• function atomic_dec_and_test
• function refcount_dec_and_test

Annotated Snippet

if (new > val) {
			REFCOUNT_WARN(new > val, "refcount_t: underflow; use-after-free.\n");
			return false;
		}

		old = atomic_cmpxchg_release(&r->refs, val, new);
		if (old == val)
			break;

		val = old;
	}

	return !new;
}

static inline __refcount_check
bool refcount_dec_and_test(refcount_t *r)
{
	return refcount_sub_and_test(1, r);
}


#endif /* _ATOMIC_LINUX_REFCOUNT_H */

Annotation

• Immediate include surface: `linux/atomic.h`, `linux/kernel.h`.
• Detected declarations: `function refcount_set`, `function refcount_set_release`, `function refcount_read`, `function atomic_inc_not_zero`, `function atomic_inc`, `function atomic_dec_and_test`, `function refcount_dec_and_test`.
• Atlas domain: Support Tooling And Documentation / tools.
• Implementation status: source implementation candidate.
• Synchronization appears in or near this file; preserve lock ordering, sleepability, and interrupt-context constraints.

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.