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 "kern_constants.h"
  13 #include "os.h"
  14 #include "process.h"
  15 #include "um_malloc.h"
  16 #include "user.h"
  17
  18 /*
  19  * Locked by irq_lock in arch/um/kernel/irq.c.  Changed by os_create_pollfd
  20  * and os_free_irq_by_cb, which are called under irq_lock.
  21  */
  22 static struct pollfd *pollfds = NULL;
  23 static int pollfds_num = 0;
  24 static int pollfds_size = 0;
  25
  26 int os_waiting_for_events(struct irq_fd *active_fds)
  27 {
  28         struct irq_fd *irq_fd;
  29         int i, n, err;
  30
  31         n = poll(pollfds, pollfds_num, 0);
  32         if (n < 0) {
  33                 err = -errno;
  34                 if (errno != EINTR)
  35                         printk(UM_KERN_ERR "os_waiting_for_events:"
  36                                " poll returned %d, errno = %d\n", n, errno);
  37                 return err;
  38         }
  39
  40         if (n == 0)
  41                 return 0;
  42
  43         irq_fd = active_fds;
  44
  45         for (i = 0; i < pollfds_num; i++) {
  46                 if (pollfds[i].revents != 0) {
  47                         irq_fd->current_events = pollfds[i].revents;
  48                         pollfds[i].fd = -1;
  49                 }
  50                 irq_fd = irq_fd->next;
  51         }
  52         return n;
  53 }
  54
  55 int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds)
  56 {
  57         if (pollfds_num == pollfds_size) {
  58                 if (size_tmpfds <= pollfds_size * sizeof(pollfds[0])) {
  59                         /* return min size needed for new pollfds area */
  60                         return (pollfds_size + 1) * sizeof(pollfds[0]);
  61                 }
  62
  63                 if (pollfds != NULL) {
  64                         memcpy(tmp_pfd, pollfds,
  65                                sizeof(pollfds[0]) * pollfds_size);
  66                         /* remove old pollfds */
  67                         kfree(pollfds);
  68                 }
  69                 pollfds = tmp_pfd;
  70                 pollfds_size++;
  71         } else
  72                 kfree(tmp_pfd); /* remove not used tmp_pfd */
  73
  74         pollfds[pollfds_num] = ((struct pollfd) { .fd           = fd,
  75                                                   .events       = events,
  76                                                   .revents      = 0 });
  77         pollfds_num++;
  78
  79         return 0;
  80 }
  81
  82 void os_free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg,
  83                 struct irq_fd *active_fds, struct irq_fd ***last_irq_ptr2)
  84 {
  85         struct irq_fd **prev;
  86         int i = 0;
  87
  88         prev = &active_fds;
  89         while (*prev != NULL) {
  90                 if ((*test)(*prev, arg)) {
  91                         struct irq_fd *old_fd = *prev;
  92                         if ((pollfds[i].fd != -1) &&
  93                             (pollfds[i].fd != (*prev)->fd)) {
  94                                 printk(UM_KERN_ERR "os_free_irq_by_cb - "
  95                                        "mismatch between active_fds and "
  96                                        "pollfds, fd %d vs %d\n",
  97                                        (*prev)->fd, pollfds[i].fd);
  98                                 goto out;
  99                         }
 100
 101                         pollfds_num--;
 102
 103                         /*
 104                          * This moves the *whole* array after pollfds[i]
 105                          * (though it doesn't spot as such)!
 106                          */
 107                         memmove(&pollfds[i], &pollfds[i + 1],
 108                                (pollfds_num - i) * sizeof(pollfds[0]));
 109                         if (*last_irq_ptr2 == &old_fd->next)
 110                                 *last_irq_ptr2 = prev;
 111
 112                         *prev = (*prev)->next;
 113                         if (old_fd->type == IRQ_WRITE)
 114                                 ignore_sigio_fd(old_fd->fd);
 115                         kfree(old_fd);
 116                         continue;
 117                 }
 118                 prev = &(*prev)->next;
 119                 i++;
 120         }
 121  out:
 122         return;
 123 }
 124
 125 int os_get_pollfd(int i)
 126 {
 127         return pollfds[i].fd;
 128 }
 129
 130 void os_set_pollfd(int i, int fd)
 131 {
 132         pollfds[i].fd = fd;
 133 }
 134
 135 void os_set_ioignore(void)
 136 {
 137         signal(SIGIO, SIG_IGN);
 138 }