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authorTakashi Iwai <tiwai@suse.de>2018-09-13 09:20:43 +0300
committerTakashi Iwai <tiwai@suse.de>2018-10-04 21:13:17 +0300
commit6aea5702e27ebc85747d6e4943a0c378e1752be0 (patch)
treec14ccb05935b7390997e8f4c74a5f4d4b2ab3617 /sound/core/rawmidi.c
parentcd3b7116b57527f659b96ff6988d2de3d448c5b3 (diff)
downloadlinux-6aea5702e27ebc85747d6e4943a0c378e1752be0.tar.xz
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>
Diffstat (limited to 'sound/core/rawmidi.c')
-rw-r--r--sound/core/rawmidi.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
index 08d5662039e3..ee601d7f0926 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,