Merge git://git.kvack.org/~bcrl/aio-next

[~andy/linux] / drivers / staging / speakup / synth.c

diff --git a/drivers/staging/speakup/synth.c b/drivers/staging/speakup/synth.c
index d867dd9109ed614fb2f0c183796aed84a8f0b2e2..0b3549bd909d0619a594155f91a3f18372eeb7be 100644 (file)
--- 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++)