include/uapi/linux/dm-ioctl.h

Source file repositories/reference/linux-study-clean/include/uapi/linux/dm-ioctl.h

File Facts

System
Linux kernel
Corpus path
include/uapi/linux/dm-ioctl.h
Extension
.h
Size
11749 bytes
Lines
391
Domain
Core OS
Bucket
Core Kernel Interface
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

struct dm_ioctl {
	/*
	 * The version number is made up of three parts:
	 * major - no backward or forward compatibility,
	 * minor - only backwards compatible,
	 * patch - both backwards and forwards compatible.
	 *
	 * All clients of the ioctl interface should fill in the
	 * version number of the interface that they were
	 * compiled with.
	 *
	 * All recognised ioctl commands (ie. those that don't
	 * return -ENOTTY) fill out this field, even if the
	 * command failed.
	 */
	__u32 version[3];	/* in/out */
	__u32 data_size;	/* total size of data passed in
				 * including this struct */

	__u32 data_start;	/* offset to start of data
				 * relative to start of this struct */

	__u32 target_count;	/* in/out */
	__s32 open_count;	/* out */
	__u32 flags;		/* in/out */

	/*
	 * event_nr holds either the event number (input and output) or the
	 * udev cookie value (input only).
	 * The DM_DEV_WAIT ioctl takes an event number as input.
	 * The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
	 * use the field as a cookie to return in the DM_COOKIE
	 * variable with the uevents they issue.
	 * For output, the ioctls return the event number, not the cookie.
	 */
	__u32 event_nr;      	/* in/out */
	__u32 padding;

	__u64 dev;		/* in/out */

	char name[DM_NAME_LEN];	/* device name */
	char uuid[DM_UUID_LEN];	/* unique identifier for
				 * the block device */
	char data[7];		/* padding or data */
};

/*
 * Used to specify tables.  These structures appear after the
 * dm_ioctl.
 */
struct dm_target_spec {
	__u64 sector_start;
	__u64 length;
	__s32 status;		/* used when reading from kernel only */

	/*
	 * Location of the next dm_target_spec.
	 * - When specifying targets on a DM_TABLE_LOAD command, this value is
	 *   the number of bytes from the start of the "current" dm_target_spec
	 *   to the start of the "next" dm_target_spec.
	 * - When retrieving targets on a DM_TABLE_STATUS command, this value
	 *   is the number of bytes from the start of the first dm_target_spec
	 *   (that follows the dm_ioctl struct) to the start of the "next"
	 *   dm_target_spec.
	 */
	__u32 next;

	char target_type[DM_MAX_TYPE_NAME];

	/*
	 * Parameter string starts immediately after this object.
	 * Be careful to add padding after string to ensure correct
	 * alignment of subsequent dm_target_spec.
	 */
};

/*
 * Used to retrieve the target dependencies.
 */
struct dm_target_deps {
	__u32 count;	/* Array size */
	__u32 padding;	/* unused */
	__u64 dev[];	/* out */
};

/*
 * Used to get a list of all dm devices.
 */
struct dm_name_list {
	__u64 dev;

Annotation

Implementation Notes