io_uring/nop.c

   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
  14 struct 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
  26 int 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
  49 int 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         }
  79 done:
  80         if (ret < 0)
  81                 req_set_fail(req);
  82         io_req_set_res(req, nop->result, 0);
  83         return IOU_OK;
  84 }