io_uring/io_uring.h

File Facts

System

Linux kernel

Corpus path

io_uring/io_uring.h

Extension

.h

Size

16369 bytes

Lines

586

Domain

Kernel Services

Bucket

io_uring

Inferred role

Kernel Services: implementation source

Status

source 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.
• 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/errno.h
• linux/lockdep.h
• linux/resume_user_mode.h
• linux/poll.h
• linux/io_uring_types.h
• uapi/linux/eventpoll.h
• alloc_cache.h
• io-wq.h
• slist.h
• tw.h
• opdef.h
• trace/events/io_uring.h

Detected Declarations

• struct io_rings_layout
• struct io_ctx_config
• struct io_defer_entry
• struct io_wait_queue
• function io_should_wake
• function io_lockdep_assert_cq_locked
• function io_is_compat
• function io_submit_flush_completions
• function io_get_cqe_overflow
• function io_get_cqe
• function io_defer_get_uncommited_cqe
• function io_fill_cqe_req
• function req_set_fail
• function io_req_set_res
• function ctx_cqe32_flags
• function io_req_set_res32
• function req_has_async_data
• function io_req_async_data_clear
• function io_req_async_data_free
• function io_put_file
• function io_ring_submit_unlock
• function io_ring_submit_lock
• function io_commit_cqring
• function __io_wq_wake
• function io_poll_wq_wake
• function io_cqring_wake
• function __io_sqring_full
• function io_sqring_full
• function __io_sqring_entries
• function io_sqring_entries
• function io_req_complete_defer
• function io_commit_cqring_flush
• function io_get_task_refs
• function io_req_cache_empty
• function io_alloc_req
• function io_req_queue_tw_complete
• function io_file_can_poll
• function io_is_uring_cmd
• function io_get_time
• function io_has_work

Annotated Snippet

struct io_rings_layout {
	/* size of CQ + headers + SQ offset array */
	size_t rings_size;
	size_t sq_size;

	size_t sq_array_offset;
};

struct io_ctx_config {
	struct io_uring_params p;
	struct io_rings_layout layout;
	struct io_uring_params __user *uptr;
};

#define IORING_FEAT_FLAGS (IORING_FEAT_SINGLE_MMAP |\
			IORING_FEAT_NODROP |\
			IORING_FEAT_SUBMIT_STABLE |\
			IORING_FEAT_RW_CUR_POS |\
			IORING_FEAT_CUR_PERSONALITY |\
			IORING_FEAT_FAST_POLL |\
			IORING_FEAT_POLL_32BITS |\
			IORING_FEAT_SQPOLL_NONFIXED |\
			IORING_FEAT_EXT_ARG |\
			IORING_FEAT_NATIVE_WORKERS |\
			IORING_FEAT_RSRC_TAGS |\
			IORING_FEAT_CQE_SKIP |\
			IORING_FEAT_LINKED_FILE |\
			IORING_FEAT_REG_REG_RING |\
			IORING_FEAT_RECVSEND_BUNDLE |\
			IORING_FEAT_MIN_TIMEOUT |\
			IORING_FEAT_RW_ATTR |\
			IORING_FEAT_NO_IOWAIT)

#define IORING_SETUP_FLAGS (IORING_SETUP_IOPOLL |\
			IORING_SETUP_SQPOLL |\
			IORING_SETUP_SQ_AFF |\
			IORING_SETUP_CQSIZE |\
			IORING_SETUP_CLAMP |\
			IORING_SETUP_ATTACH_WQ |\
			IORING_SETUP_R_DISABLED |\
			IORING_SETUP_SUBMIT_ALL |\
			IORING_SETUP_COOP_TASKRUN |\
			IORING_SETUP_TASKRUN_FLAG |\
			IORING_SETUP_SQE128 |\
			IORING_SETUP_CQE32 |\
			IORING_SETUP_SINGLE_ISSUER |\
			IORING_SETUP_DEFER_TASKRUN |\
			IORING_SETUP_NO_MMAP |\
			IORING_SETUP_REGISTERED_FD_ONLY |\
			IORING_SETUP_NO_SQARRAY |\
			IORING_SETUP_HYBRID_IOPOLL |\
			IORING_SETUP_CQE_MIXED |\
			IORING_SETUP_SQE_MIXED |\
			IORING_SETUP_SQ_REWIND)

#define IORING_ENTER_FLAGS (IORING_ENTER_GETEVENTS |\
			IORING_ENTER_SQ_WAKEUP |\
			IORING_ENTER_SQ_WAIT |\
			IORING_ENTER_EXT_ARG |\
			IORING_ENTER_REGISTERED_RING |\
			IORING_ENTER_ABS_TIMER |\
			IORING_ENTER_EXT_ARG_REG |\
			IORING_ENTER_NO_IOWAIT)


#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE |\
			IOSQE_IO_DRAIN |\
			IOSQE_IO_LINK |\
			IOSQE_IO_HARDLINK |\
			IOSQE_ASYNC |\
			IOSQE_BUFFER_SELECT |\
			IOSQE_CQE_SKIP_SUCCESS)

#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)

/*
 * Complaint timeout for io_uring cancelation exits, and for io-wq exit
 * worker waiting.
 */
#define IO_URING_EXIT_WAIT_MAX	(HZ * 60 * 5)

enum {
	IOU_COMPLETE		= 0,

	IOU_ISSUE_SKIP_COMPLETE	= -EIOCBQUEUED,

	/*
	 * The request has more work to do and should be retried. io_uring will
	 * attempt to wait on the file for eligible opcodes, but otherwise
	 * it'll be handed to iowq for blocking execution. It works for normal

Annotation

• Immediate include surface: `linux/errno.h`, `linux/lockdep.h`, `linux/resume_user_mode.h`, `linux/poll.h`, `linux/io_uring_types.h`, `uapi/linux/eventpoll.h`, `alloc_cache.h`, `io-wq.h`.
• Detected declarations: `struct io_rings_layout`, `struct io_ctx_config`, `struct io_defer_entry`, `struct io_wait_queue`, `function io_should_wake`, `function io_lockdep_assert_cq_locked`, `function io_is_compat`, `function io_submit_flush_completions`, `function io_get_cqe_overflow`, `function io_get_cqe`.
• Atlas domain: Kernel Services / io_uring.
• Implementation status: source 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.