arch/um/os-Linux/irq.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include <stdlib.h>
   7 #include <errno.h>
   8 #include <poll.h>
   9 #include <signal.h>
  10 #include <string.h>
  11 #include "irq_user.h"
  12 #include "os.h"
  13 #include "um_malloc.h"
  14
  15 /*
  16  * Locked by irq_lock in arch/um/kernel/irq.c.  Changed by os_create_pollfd
  17  * and os_free_irq_by_cb, which are called under irq_lock.
  18  */
  19 static struct pollfd *pollfds = NULL;
  20 static int pollfds_num = 0;
  21 static int pollfds_size = 0;
  22
  23 int os_waiting_for_events(struct irq_fd *active_fds)
  24 {
  25         struct irq_fd *irq_fd;
  26         int i, n, err;
  27
  28         n = poll(pollfds, pollfds_num, 0);
  29         if (n < 0) {
  30                 err = -errno;
  31                 if (errno != EINTR)
  32                         printk(UM_KERN_ERR "os_waiting_for_events:"
  33                                " poll returned %d, errno = %d\n", n, errno);
  34                 return err;
  35         }
  36
  37         if (n == 0)
  38                 return 0;
  39
  40         irq_fd = active_fds;
  41
  42         for (i = 0; i < pollfds_num; i++) {
  43                 if (pollfds[i].revents != 0) {
  44                         irq_fd->current_events = pollfds[i].revents;
  45                         pollfds[i].fd = -1;
  46                 }
  47                 irq_fd = irq_fd->next;
  48         }
  49         return n;
  50 }
  51
  52 int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds)
  53 {
  54         if (pollfds_num == pollfds_size) {
  55                 if (size_tmpfds <= pollfds_size * sizeof(pollfds[0])) {
  56                         /* return min size needed for new pollfds area */
  57                         return (pollfds_size + 1) * sizeof(pollfds[0]);
  58                 }
  59
  60                 if (pollfds != NULL) {
  61                         memcpy(tmp_pfd, pollfds,
  62                                sizeof(pollfds[0]) * pollfds_size);
  63                         /* remove old pollfds */
  64                         kfree(pollfds);
  65                 }
  66                 pollfds = tmp_pfd;
  67                 pollfds_size++;
  68         } else
  69                 kfree(tmp_pfd); /* remove not used tmp_pfd */
  70
  71         pollfds[pollfds_num] = ((struct pollfd) { .fd           = fd,
  72                                                   .events       = events,
  73                                                   .revents      = 0 });
  74         pollfds_num++;
  75
  76         return 0;
  77 }
  78
  79 void os_free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg,
  80                 struct irq_fd *active_fds, struct irq_fd ***last_irq_ptr2)
  81 {
  82         struct irq_fd **prev;
  83         int i = 0;
  84
  85         prev = &active_fds;
  86         while (*prev != NULL) {
  87                 if ((*test)(*prev, arg)) {
  88                         struct irq_fd *old_fd = *prev;
  89                         if ((pollfds[i].fd != -1) &&
  90                             (pollfds[i].fd != (*prev)->fd)) {
  91                                 printk(UM_KERN_ERR "os_free_irq_by_cb - "
  92                                        "mismatch between active_fds and "
  93                                        "pollfds, fd %d vs %d\n",
  94                                        (*prev)->fd, pollfds[i].fd);
  95                                 goto out;
  96                         }
  97
  98                         pollfds_num--;
  99
 100                         /*
 101                          * This moves the *whole* array after pollfds[i]
 102                          * (though it doesn't spot as such)!
 103                          */
 104                         memmove(&pollfds[i], &pollfds[i + 1],
 105                                (pollfds_num - i) * sizeof(pollfds[0]));
 106                         if (*last_irq_ptr2 == &old_fd->next)
 107                                 *last_irq_ptr2 = prev;
 108
 109                         *prev = (*prev)->next;
 110                         if (old_fd->type == IRQ_WRITE)
 111                                 ignore_sigio_fd(old_fd->fd);
 112                         kfree(old_fd);
 113                         continue;
 114                 }
 115                 prev = &(*prev)->next;
 116                 i++;
 117         }
 118  out:
 119         return;
 120 }
 121
 122 int os_get_pollfd(int i)
 123 {
 124         return pollfds[i].fd;
 125 }
 126
 127 void os_set_pollfd(int i, int fd)
 128 {
 129         pollfds[i].fd = fd;
 130 }
 131
 132 void os_set_ioignore(void)
 133 {
 134         signal(SIGIO, SIG_IGN);
 135 }