diff options
Diffstat (limited to 'drivers/staging/speakup/synth.c')
| -rw-r--r-- | drivers/staging/speakup/synth.c | 38 |
1 files changed, 25 insertions, 13 deletions
diff --git a/drivers/staging/speakup/synth.c b/drivers/staging/speakup/synth.c index d867dd9109ed..0b3549bd909d 100644 --- a/drivers/staging/speakup/synth.c +++ b/drivers/staging/speakup/synth.c @@ -25,6 +25,18 @@ static int module_status; bool spk_quiet_boot; struct speakup_info_t speakup_info = { + /* + * This spinlock is used to protect the entire speakup machinery, and + * must be taken at each kernel->speakup transition and released at + * each corresponding speakup->kernel transition. + * + * The progression thread only interferes with the speakup machinery through + * the synth buffer, so only needs to take the lock while tinkering with + * the buffer. + * + * We use spin_lock/trylock_irqsave and spin_unlock_irqrestore with this + * spinlock because speakup needs to disable the keyboard IRQ. + */ .spinlock = __SPIN_LOCK_UNLOCKED(speakup_info.spinlock), .flushing = 0, }; @@ -83,27 +95,27 @@ void spk_do_catch_up(struct spk_synth *synth) full_time = spk_get_var(FULL); delay_time = spk_get_var(DELAY); - spk_lock(flags); + spin_lock_irqsave(&speakup_info.spinlock, flags); jiffy_delta_val = jiffy_delta->u.n.value; - spk_unlock(flags); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); jiff_max = jiffies + jiffy_delta_val; while (!kthread_should_stop()) { - spk_lock(flags); + spin_lock_irqsave(&speakup_info.spinlock, flags); if (speakup_info.flushing) { speakup_info.flushing = 0; - spk_unlock(flags); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); synth->flush(synth); continue; } if (synth_buffer_empty()) { - spk_unlock(flags); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); break; } ch = synth_buffer_peek(); set_current_state(TASK_INTERRUPTIBLE); full_time_val = full_time->u.n.value; - spk_unlock(flags); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); if (ch == '\n') ch = synth->procspeech; if (!spk_serial_out(ch)) { @@ -111,11 +123,11 @@ void spk_do_catch_up(struct spk_synth *synth) continue; } if ((jiffies >= jiff_max) && (ch == SPACE)) { - spk_lock(flags); + spin_lock_irqsave(&speakup_info.spinlock, flags); jiffy_delta_val = jiffy_delta->u.n.value; delay_time_val = delay_time->u.n.value; full_time_val = full_time->u.n.value; - spk_unlock(flags); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); if (spk_serial_out(synth->procspeech)) schedule_timeout( msecs_to_jiffies(delay_time_val)); @@ -125,9 +137,9 @@ void spk_do_catch_up(struct spk_synth *synth) jiff_max = jiffies + jiffy_delta_val; } set_current_state(TASK_RUNNING); - spk_lock(flags); + spin_lock_irqsave(&speakup_info.spinlock, flags); synth_buffer_getc(); - spk_unlock(flags); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); } spk_serial_out(synth->procspeech); } @@ -145,7 +157,7 @@ const char *spk_synth_immediate(struct spk_synth *synth, const char *buff) return buff; buff++; } - return 0; + return NULL; } EXPORT_SYMBOL_GPL(spk_synth_immediate); @@ -403,11 +415,11 @@ void synth_release(void) if (synth == NULL) return; - spk_lock(flags); + spin_lock_irqsave(&speakup_info.spinlock, flags); pr_info("releasing synth %s\n", synth->name); synth->alive = 0; del_timer(&thread_timer); - spk_unlock(flags); + spin_unlock_irqrestore(&speakup_info.spinlock, flags); if (synth->attributes.name) sysfs_remove_group(speakup_kobj, &(synth->attributes)); for (var = synth->vars; var->var_id != MAXVARS; var++) |