arch/s390/hypfs/hypfs_dbfs.c

File Facts

System

Linux kernel

Corpus path

arch/s390/hypfs/hypfs_dbfs.c

Extension

.c

Size

2812 bytes

Lines

129

Domain

Architecture Layer

Bucket

arch/s390

Inferred role

Architecture Layer: operation-table or driver-model contract

Status

pattern implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

• CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Uses kernel synchronization; read lock ordering, sleepability, and interrupt context assumptions before translating.
• Allocates kernel memory; connect allocation flags and lifetime to context constraints.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• linux/security.h
• linux/slab.h
• hypfs.h

Detected Declarations

• function hypfs_dbfs_data_free
• function dbfs_read
• function dbfs_ioctl
• function hypfs_dbfs_create_file
• function hypfs_dbfs_remove_file
• function hypfs_dbfs_init
• module init hypfs_dbfs_init

Annotated Snippet

static const struct file_operations dbfs_ops_ioctl = {
	.read		= dbfs_read,
	.unlocked_ioctl = dbfs_ioctl,
};

static const struct file_operations dbfs_ops = {
	.read		= dbfs_read,
};

void hypfs_dbfs_create_file(struct hypfs_dbfs_file *df)
{
	const struct file_operations *fops = &dbfs_ops;

	if (df->unlocked_ioctl && !security_locked_down(LOCKDOWN_DEBUGFS))
		fops = &dbfs_ops_ioctl;
	df->dentry = debugfs_create_file(df->name, 0400, dbfs_dir, df, fops);
	mutex_init(&df->lock);
}

void hypfs_dbfs_remove_file(struct hypfs_dbfs_file *df)
{
	debugfs_remove(df->dentry);
}

static int __init hypfs_dbfs_init(void)
{
	int rc = -ENODATA;

	dbfs_dir = debugfs_create_dir("s390_hypfs", NULL);
	if (hypfs_diag_init())
		goto fail_dbfs_exit;
	if (hypfs_vm_init())
		goto fail_hypfs_diag_exit;
	hypfs_sprp_init();
	if (hypfs_diag0c_init())
		goto fail_hypfs_sprp_exit;
	rc = hypfs_fs_init();
	if (rc)
		goto fail_hypfs_diag0c_exit;
	return 0;

fail_hypfs_diag0c_exit:
	hypfs_diag0c_exit();
fail_hypfs_sprp_exit:
	hypfs_sprp_exit();
	hypfs_vm_exit();
fail_hypfs_diag_exit:
	hypfs_diag_exit();
	pr_err("Initialization of hypfs failed with rc=%i\n", rc);
fail_dbfs_exit:
	debugfs_remove(dbfs_dir);
	return rc;
}
device_initcall(hypfs_dbfs_init)

Annotation

• Immediate include surface: `linux/security.h`, `linux/slab.h`, `hypfs.h`.
• Detected declarations: `function hypfs_dbfs_data_free`, `function dbfs_read`, `function dbfs_ioctl`, `function hypfs_dbfs_create_file`, `function hypfs_dbfs_remove_file`, `function hypfs_dbfs_init`, `module init hypfs_dbfs_init`.
• Atlas domain: Architecture Layer / arch/s390.
• Implementation status: pattern 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.