drivers/input/serio/userio.c

File Facts

System

Linux kernel

Corpus path

drivers/input/serio/userio.c

Extension

.c

Size

6711 bytes

Lines

284

Domain

Driver Families

Bucket

drivers/input

Inferred role

Driver Families: operation-table or driver-model contract

Status

pattern implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

• Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.
• Defines an operation table; this is where Linux turns generic core objects into subsystem-specific behavior.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• 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/circ_buf.h
• linux/mutex.h
• linux/module.h
• linux/init.h
• linux/kernel.h
• linux/serio.h
• linux/slab.h
• linux/fs.h
• linux/miscdevice.h
• linux/sched.h
• linux/poll.h
• uapi/linux/userio.h

Detected Declarations

• struct userio_device
• function userio_device_write
• function scoped_guard
• function userio_char_open
• function userio_char_release
• function userio_fetch_data
• function userio_char_read
• function userio_execute_cmd
• function userio_char_write
• function scoped_cond_guard
• function userio_char_poll

Annotated Snippet

static const struct file_operations userio_fops = {
	.owner		= THIS_MODULE,
	.open		= userio_char_open,
	.release	= userio_char_release,
	.read		= userio_char_read,
	.write		= userio_char_write,
	.poll		= userio_char_poll,
};

static struct miscdevice userio_misc = {
	.fops	= &userio_fops,
	.minor	= USERIO_MINOR,
	.name	= USERIO_NAME,
};
module_driver(userio_misc, misc_register, misc_deregister);

MODULE_ALIAS_MISCDEV(USERIO_MINOR);
MODULE_ALIAS("devname:" USERIO_NAME);

MODULE_AUTHOR("Stephen Chandler Paul <thatslyude@gmail.com>");
MODULE_DESCRIPTION("Virtual Serio Device Support");
MODULE_LICENSE("GPL");

Annotation

• Immediate include surface: `linux/circ_buf.h`, `linux/mutex.h`, `linux/module.h`, `linux/init.h`, `linux/kernel.h`, `linux/serio.h`, `linux/slab.h`, `linux/fs.h`.
• Detected declarations: `struct userio_device`, `function userio_device_write`, `function scoped_guard`, `function userio_char_open`, `function userio_char_release`, `function userio_fetch_data`, `function userio_char_read`, `function userio_execute_cmd`, `function userio_char_write`, `function scoped_cond_guard`.
• Atlas domain: Driver Families / drivers/input.
• Implementation status: pattern implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.
• 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.