io_uring/nop.c

Source file repositories/reference/linux-study-clean/io_uring/nop.c

File Facts

System
Linux kernel
Corpus path
io_uring/nop.c
Extension
.c
Size
2208 bytes
Lines
91
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.

Dependency Surface

Detected Declarations

Annotated Snippet

struct io_nop {
	struct file     *file;
	int             result;
	int		fd;
	unsigned int	flags;
	__u64		extra1;
	__u64		extra2;
};

#define NOP_FLAGS	(IORING_NOP_INJECT_RESULT | IORING_NOP_FIXED_FILE | \
			 IORING_NOP_FIXED_BUFFER | IORING_NOP_FILE | \
			 IORING_NOP_TW | IORING_NOP_CQE32)

int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
	struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);

	nop->flags = READ_ONCE(sqe->nop_flags);
	if (nop->flags & ~NOP_FLAGS)
		return -EINVAL;

	if (nop->flags & IORING_NOP_INJECT_RESULT)
		nop->result = READ_ONCE(sqe->len);
	else
		nop->result = 0;
	if (nop->flags & IORING_NOP_FILE)
		nop->fd = READ_ONCE(sqe->fd);
	else
		nop->fd = -1;
	if (nop->flags & IORING_NOP_FIXED_BUFFER)
		req->buf_index = READ_ONCE(sqe->buf_index);
	if (nop->flags & IORING_NOP_CQE32) {
		struct io_ring_ctx *ctx = req->ctx;

		if (!(ctx->flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED)))
			return -EINVAL;
		nop->extra1 = READ_ONCE(sqe->off);
		nop->extra2 = READ_ONCE(sqe->addr);
	}
	return 0;
}

int io_nop(struct io_kiocb *req, unsigned int issue_flags)
{
	struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);
	int ret = nop->result;

	if (nop->flags & IORING_NOP_FILE) {
		if (nop->flags & IORING_NOP_FIXED_FILE) {
			req->file = io_file_get_fixed(req, nop->fd, issue_flags);
			req->flags |= REQ_F_FIXED_FILE;
		} else {
			req->file = io_file_get_normal(req, nop->fd);
		}
		if (!req->file) {
			ret = -EBADF;
			goto done;
		}
	}
	if (nop->flags & IORING_NOP_FIXED_BUFFER) {
		if (!io_find_buf_node(req, issue_flags))
			ret = -EFAULT;
	}
done:
	if (ret < 0)
		req_set_fail(req);
	if (nop->flags & IORING_NOP_CQE32)
		io_req_set_res32(req, ret, 0, nop->extra1, nop->extra2);
	else
		io_req_set_res(req, ret, 0);
	if (nop->flags & IORING_NOP_TW) {
		req->io_task_work.func = io_req_task_complete;
		io_req_task_work_add(req);
		return IOU_ISSUE_SKIP_COMPLETE;
	}
	return IOU_COMPLETE;
}

Annotation

Implementation Notes