root/arch/um/drivers/ubd_user.c

DEFINITIONS

1. start_io_thread
2. ubd_read_poll
3. ubd_write_poll

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2016 Anton Ivanov (aivanov@brocade.com)
   4  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
   5  * Copyright (C) 2001 Ridgerun,Inc (glonnon@ridgerun.com)
   6  */
   7 
   8 #include <stddef.h>
   9 #include <unistd.h>
  10 #include <errno.h>
  11 #include <sched.h>
  12 #include <signal.h>
  13 #include <string.h>
  14 #include <netinet/in.h>
  15 #include <sys/time.h>
  16 #include <sys/socket.h>
  17 #include <sys/mman.h>
  18 #include <sys/param.h>
  19 #include <endian.h>
  20 #include <byteswap.h>
  21 
  22 #include "ubd.h"
  23 #include <os.h>
  24 #include <poll.h>
  25 
  26 struct pollfd kernel_pollfd;
  27 
  28 int start_io_thread(unsigned long sp, int *fd_out)
  29 {
  30         int pid, fds[2], err;
  31 
  32         err = os_pipe(fds, 1, 1);
  33         if(err < 0){
  34                 printk("start_io_thread - os_pipe failed, err = %d\n", -err);
  35                 goto out;
  36         }
  37 
  38         kernel_fd = fds[0];
  39         kernel_pollfd.fd = kernel_fd;
  40         kernel_pollfd.events = POLLIN;
  41         *fd_out = fds[1];
  42 
  43         err = os_set_fd_block(*fd_out, 0);
  44         err = os_set_fd_block(kernel_fd, 0);
  45         if (err) {
  46                 printk("start_io_thread - failed to set nonblocking I/O.\n");
  47                 goto out_close;
  48         }
  49 
  50         pid = clone(io_thread, (void *) sp, CLONE_FILES | CLONE_VM, NULL);
  51         if(pid < 0){
  52                 err = -errno;
  53                 printk("start_io_thread - clone failed : errno = %d\n", errno);
  54                 goto out_close;
  55         }
  56 
  57         return(pid);
  58 
  59  out_close:
  60         os_close_file(fds[0]);
  61         os_close_file(fds[1]);
  62         kernel_fd = -1;
  63         *fd_out = -1;
  64  out:
  65         return err;
  66 }
  67 
  68 int ubd_read_poll(int timeout)
  69 {
  70         kernel_pollfd.events = POLLIN;
  71         return poll(&kernel_pollfd, 1, timeout);
  72 }
  73 int ubd_write_poll(int timeout)
  74 {
  75         kernel_pollfd.events = POLLOUT;
  76         return poll(&kernel_pollfd, 1, timeout);
  77 }
  78