1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/kernel.h>
 3#include <linux/errno.h>
 4#include <linux/fs.h>
 5#include <linux/file.h>
 6#include <linux/io_uring.h>
 7
 8#include <uapi/linux/io_uring.h>
 9
10#include "io_uring.h"
11#include "rsrc.h"
12#include "nop.h"
13
14struct io_nop {
15	/* NOTE: kiocb has the file as the first member, so don't do it here */
16	struct file     *file;
17	int             result;
18	int		fd;
19	int		buffer;
20	unsigned int	flags;
21};
22
23#define NOP_FLAGS	(IORING_NOP_INJECT_RESULT | IORING_NOP_FIXED_FILE | \
24			 IORING_NOP_FIXED_BUFFER | IORING_NOP_FILE)
25
26int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
27{
28	struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);
29
30	nop->flags = READ_ONCE(sqe->nop_flags);
31	if (nop->flags & ~NOP_FLAGS)
32		return -EINVAL;
33
34	if (nop->flags & IORING_NOP_INJECT_RESULT)
35		nop->result = READ_ONCE(sqe->len);
36	else
37		nop->result = 0;
38	if (nop->flags & IORING_NOP_FILE)
39		nop->fd = READ_ONCE(sqe->fd);
40	else
41		nop->fd = -1;
42	if (nop->flags & IORING_NOP_FIXED_BUFFER)
43		nop->buffer = READ_ONCE(sqe->buf_index);
44	else
45		nop->buffer = -1;
46	return 0;
47}
48
49int io_nop(struct io_kiocb *req, unsigned int issue_flags)
50{
51	struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);
52	int ret = nop->result;
53
54	if (nop->flags & IORING_NOP_FILE) {
55		if (nop->flags & IORING_NOP_FIXED_FILE) {
56			req->file = io_file_get_fixed(req, nop->fd, issue_flags);
57			req->flags |= REQ_F_FIXED_FILE;
58		} else {
59			req->file = io_file_get_normal(req, nop->fd);
60		}
61		if (!req->file) {
62			ret = -EBADF;
63			goto done;
64		}
65	}
66	if (nop->flags & IORING_NOP_FIXED_BUFFER) {
67		struct io_ring_ctx *ctx = req->ctx;
68		struct io_rsrc_node *node;
69
70		ret = -EFAULT;
71		io_ring_submit_lock(ctx, issue_flags);
72		node = io_rsrc_node_lookup(&ctx->buf_table, nop->buffer);
73		if (node) {
74			io_req_assign_buf_node(req, node);
75			ret = 0;
76		}
77		io_ring_submit_unlock(ctx, issue_flags);
78	}
79done:
80	if (ret < 0)
81		req_set_fail(req);
82	io_req_set_res(req, nop->result, 0);
83	return IOU_OK;
84}