root/drivers/staging/speakup/thread.c

DEFINITIONS

1. speakup_thread

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/kthread.h>
   3 #include <linux/wait.h>
   4 
   5 #include "spk_types.h"
   6 #include "speakup.h"
   7 #include "spk_priv.h"
   8 
   9 DECLARE_WAIT_QUEUE_HEAD(speakup_event);
  10 EXPORT_SYMBOL_GPL(speakup_event);
  11 
  12 int speakup_thread(void *data)
  13 {
  14         unsigned long flags;
  15         int should_break;
  16         struct bleep our_sound;
  17 
  18         our_sound.active = 0;
  19         our_sound.freq = 0;
  20         our_sound.jiffies = 0;
  21 
  22         mutex_lock(&spk_mutex);
  23         while (1) {
  24                 DEFINE_WAIT(wait);
  25 
  26                 while (1) {
  27                         spin_lock_irqsave(&speakup_info.spinlock, flags);
  28                         our_sound = spk_unprocessed_sound;
  29                         spk_unprocessed_sound.active = 0;
  30                         prepare_to_wait(&speakup_event, &wait,
  31                                         TASK_INTERRUPTIBLE);
  32                         should_break = kthread_should_stop() ||
  33                                 our_sound.active ||
  34                                 (synth && synth->catch_up && synth->alive &&
  35                                         (speakup_info.flushing ||
  36                                         !synth_buffer_empty()));
  37                         spin_unlock_irqrestore(&speakup_info.spinlock, flags);
  38                         if (should_break)
  39                                 break;
  40                         mutex_unlock(&spk_mutex);
  41                         schedule();
  42                         mutex_lock(&spk_mutex);
  43                 }
  44                 finish_wait(&speakup_event, &wait);
  45                 if (kthread_should_stop())
  46                         break;
  47 
  48                 if (our_sound.active)
  49                         kd_mksound(our_sound.freq, our_sound.jiffies);
  50                 if (synth && synth->catch_up && synth->alive) {
  51                         /*
  52                          * It is up to the callee to take the lock, so that it
  53                          * can sleep whenever it likes
  54                          */
  55                         synth->catch_up(synth);
  56                 }
  57 
  58                 speakup_start_ttys();
  59         }
  60         mutex_unlock(&spk_mutex);
  61         return 0;
  62 }