staging: most: make function most_submit_mbo return void

Function most_submit_mbo() causes an exception only if either the pointer
mbo or mbo->context equals NULL. From the underlying architecture's point
of view both cases must _not_ come true and would happen only, if something
has tampered with the pointers. This would render runtime code unable to
recover anyway. So, instead trying to hide that things are already
critically out of control we're better off with a WARN_ON() assertion.

This patch replaces the return type of the function most_submit_mbo() with
'void' and adds a WARN_ONCE() assertion. Additionally, code calling the
function is adapted accordingly.
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/aim-cdev/cdev.c

@@ -214,10 +214,7 @@ static ssize_t aim_write(struct file *filp, const char __user *buf,
 		goto put_mbo;
 	}
 
-	ret = most_submit_mbo(mbo);
-	if (ret)
-		goto put_mbo;
-
+	most_submit_mbo(mbo);
 	mutex_unlock(&c->io_mutex);
 	return actual_len;
 put_mbo:

drivers/staging/most/aim-sound/sound.c

@@ -234,7 +234,6 @@ static int playback_thread(void *data)
 	while (!kthread_should_stop()) {
 		struct mbo *mbo = NULL;
 		bool period_elapsed = false;
-		int ret;
 
 		wait_event_interruptible(
 			channel->playback_waitq,
@@ -250,10 +249,7 @@ static int playback_thread(void *data)
 		else
 			memset(mbo->virt_address, 0, mbo->buffer_length);
 
-		ret = most_submit_mbo(mbo);
-		if (ret)
-			channel->is_stream_running = false;
-
+		most_submit_mbo(mbo);
 		if (period_elapsed)
 			snd_pcm_period_elapsed(channel->substream);
 	}

drivers/staging/most/mostcore/core.c

@@ -1323,17 +1323,14 @@ static int arm_mbo_chain(struct most_c_obj *c, int dir,
 /**
  * most_submit_mbo - submits an MBO to fifo
  * @mbo: pointer to the MBO
- *
  */
-int most_submit_mbo(struct mbo *mbo)
+void most_submit_mbo(struct mbo *mbo)
 {
-	if (unlikely((!mbo) || (!mbo->context))) {
-		pr_err("Bad MBO or missing channel reference\n");
-		return -EINVAL;
-	}
+	if (WARN_ONCE(!mbo || !mbo->context,
+		      "bad mbo or missing channel reference\n"))
+		return;
 
 	nq_hdm_mbo(mbo);
-	return 0;
 }
 EXPORT_SYMBOL_GPL(most_submit_mbo);
 

drivers/staging/most/mostcore/mostcore.h

@@ -287,7 +287,7 @@ struct kobject *most_register_interface(struct most_interface *iface);
  * @intf_instance Pointer to the interface instance description.
  */
 void most_deregister_interface(struct most_interface *iface);
-int most_submit_mbo(struct mbo *mbo);
+void most_submit_mbo(struct mbo *mbo);
 
 /**
  * most_stop_enqueue - prevents core from enqueing MBOs