ALSA: rawmidi: A lightweight function to discard pending bytes
For discarding the pending bytes on rawmidi, we process with a loop of
snd_rawmidi_transmit() which is just a waste of CPU power.
Implement a lightweight API function to discard the pending bytes and
the proceed the ring buffer instantly, and use it instead of open
codes.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 08d5662..ee601d7 100644
--- a/sound/core/rawmidi.c
+++ b/sound/core/rawmidi.c
@@ -1236,6 +1236,28 @@ int snd_rawmidi_transmit(struct snd_rawmidi_substream *substream,
}
EXPORT_SYMBOL(snd_rawmidi_transmit);
+/**
+ * snd_rawmidi_proceed - Discard the all pending bytes and proceed
+ * @substream: rawmidi substream
+ *
+ * Return: the number of discarded bytes
+ */
+int snd_rawmidi_proceed(struct snd_rawmidi_substream *substream)
+{
+ struct snd_rawmidi_runtime *runtime = substream->runtime;
+ unsigned long flags;
+ int count = 0;
+
+ spin_lock_irqsave(&runtime->lock, flags);
+ if (runtime->avail < runtime->buffer_size) {
+ count = runtime->buffer_size - runtime->avail;
+ __snd_rawmidi_transmit_ack(substream, count);
+ }
+ spin_unlock_irqrestore(&runtime->lock, flags);
+ return count;
+}
+EXPORT_SYMBOL(snd_rawmidi_proceed);
+
static long snd_rawmidi_kernel_write1(struct snd_rawmidi_substream *substream,
const unsigned char __user *userbuf,
const unsigned char *kernelbuf,