Documentation/userspace-api/ioctl/hdio.rst

File Facts

System

Linux kernel

Corpus path

Documentation/userspace-api/ioctl/hdio.rst

Extension

.rst

Size

15817 bytes

Lines

548

Domain

Support Tooling And Documentation

Bucket

Documentation

Inferred role

Support Tooling And Documentation: documentation

Status

atlas-only

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

• No C-style include directives detected by the generator.

Detected Declarations

• No top-level syscall, struct, function, initcall, or export declaration detected by the generator.

Annotated Snippet

==============================
Summary of `HDIO_` ioctl calls
==============================

- Edward A. Falk <efalk@google.com>

November, 2004

This document attempts to describe the ioctl(2) calls supported by
the HD/IDE layer.  These are by-and-large implemented (as of Linux 5.11)
drivers/ata/libata-scsi.c.

ioctl values are listed in <linux/hdreg.h>.  As of this writing, they
are as follows:

    ioctls that pass argument pointers to user space:

	=======================	=======================================
	HDIO_GETGEO		get device geometry
	HDIO_GET_32BIT		get current io_32bit setting
	HDIO_GET_IDENTITY	get IDE identification info
	HDIO_DRIVE_TASKFILE	execute raw taskfile
	HDIO_DRIVE_TASK		execute task and special drive command
	HDIO_DRIVE_CMD		execute a special drive command
	=======================	=======================================

    ioctls that pass non-pointer values:

	=======================	=======================================
	HDIO_SET_32BIT		change io_32bit flags
	=======================	=======================================


The information that follows was determined from reading kernel source
code.  It is likely that some corrections will be made over time.

------------------------------------------------------------------------------

General:

	Unless otherwise specified, all ioctl calls return 0 on success
	and -1 with errno set to an appropriate value on error.

	Unless otherwise specified, all ioctl calls return -1 and set
	errno to EFAULT on a failed attempt to copy data to or from user
	address space.

	Unless otherwise specified, all data structures and constants
	are defined in <linux/hdreg.h>

------------------------------------------------------------------------------

HDIO_GETGEO
	get device geometry


	usage::

	  struct hd_geometry geom;

	  ioctl(fd, HDIO_GETGEO, &geom);


	inputs:
		none



	outputs:
		hd_geometry structure containing:

Annotation

• Atlas domain: Support Tooling And Documentation / Documentation.
• Implementation status: atlas-only.

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.