io_uring/register.c

File Facts

System

Linux kernel

Corpus path

io_uring/register.c

Extension

.c

Size

26320 bytes

Lines

1039

Domain

Kernel Services

Bucket

io_uring

Inferred role

Kernel Services: syscall or user/kernel boundary

Status

core implementation candidate

Why This File Exists

Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.

• Shared kernel service surface used by multiple subsystems, including helpers, cryptography, virtualization support, and async I/O infrastructure.
• Defines or participates in a user/kernel boundary; inspect argument validation, copy_from_user/copy_to_user, credentials, and dispatch target.
• 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/kernel.h
• linux/errno.h
• linux/syscalls.h
• linux/refcount.h
• linux/bits.h
• linux/fs.h
• linux/file.h
• linux/slab.h
• linux/uaccess.h
• linux/nospec.h
• linux/compat.h
• linux/io_uring.h
• linux/io_uring_types.h
• filetable.h
• io_uring.h
• opdef.h
• tctx.h
• rsrc.h
• sqpoll.h
• register.h
• cancel.h
• kbuf.h
• napi.h
• eventfd.h
• msg_ring.h
• memmap.h
• zcrx.h
• query.h
• bpf_filter.h

Detected Declarations

• syscall io_uring_register
• struct io_ring_ctx_rings
• function io_uring_register
• function io_unregister_personality
• function io_register_personality
• function io_parse_restrictions
• function io_register_restrictions
• function io_register_restrictions_task
• function io_register_bpf_filter_task
• function io_register_enable_rings
• function __io_register_iowq_aff
• function io_register_iowq_aff
• function io_unregister_iowq_aff
• function io_register_iowq_max_workers
• function io_register_clock
• function io_register_free_rings
• function io_register_resize_rings
• function io_register_mem_region
• function __io_uring_register
• function io_uring_register_send_msg_ring
• function io_uring_register_blind

Annotated Snippet

SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
		void __user *, arg, unsigned int, nr_args)
{
	struct io_ring_ctx *ctx;
	long ret = -EBADF;
	struct file *file;
	bool use_registered_ring;

	use_registered_ring = !!(opcode & IORING_REGISTER_USE_REGISTERED_RING);
	opcode &= ~IORING_REGISTER_USE_REGISTERED_RING;

	if (opcode >= IORING_REGISTER_LAST)
		return -EINVAL;

	if (fd == -1)
		return io_uring_register_blind(opcode, arg, nr_args);

	file = io_uring_ctx_get_file(fd, use_registered_ring);
	if (IS_ERR(file))
		return PTR_ERR(file);
	ctx = file->private_data;

	mutex_lock(&ctx->uring_lock);
	ret = __io_uring_register(ctx, opcode, arg, nr_args);

	trace_io_uring_register(ctx, opcode, ctx->file_table.data.nr,
				ctx->buf_table.nr, ret);
	mutex_unlock(&ctx->uring_lock);

	if (!use_registered_ring)
		fput(file);
	return ret;
}

Annotation

• Immediate include surface: `linux/kernel.h`, `linux/errno.h`, `linux/syscalls.h`, `linux/refcount.h`, `linux/bits.h`, `linux/fs.h`, `linux/file.h`, `linux/slab.h`.
• Detected declarations: `syscall io_uring_register`, `struct io_ring_ctx_rings`, `function io_uring_register`, `function io_unregister_personality`, `function io_register_personality`, `function io_parse_restrictions`, `function io_register_restrictions`, `function io_register_restrictions_task`, `function io_register_bpf_filter_task`, `function io_register_enable_rings`.
• Atlas domain: Kernel Services / io_uring.
• Implementation status: core 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.