sound: rawmidi: fix double init when opening MIDI device with O_APPEND

Commit 9a1b64c in 2.6.30 moved the substream initialization code to where it would be executed every time the substream is opened. This had the consequence that any further opening would drop and leak the data in the existing buffer, and that the device driver's open callback would be called multiple times, unexpectedly. Signed-off-by: Clemens Ladisch <[email protected]> Cc: <[email protected]> Signed-off-by: Takashi Iwai <[email protected]>
makiko-fly · Nov 10, 2009 · 8579d2d · 8579d2d
1 parent dede17b
commit 8579d2d
Showing 1 changed file with 12 additions and 10 deletions.
diff --git a/sound/core/rawmidi.c b/sound/core/rawmidi.c
@@ -266,17 +266,19 @@ static int open_substream(struct snd_rawmidi *rmidi,
 {
 	int err;
 
-	err = snd_rawmidi_runtime_create(substream);
-	if (err < 0)
-		return err;
-	err = substream->ops->open(substream);
-	if (err < 0)
-		return err;
-	substream->opened = 1;
-	if (substream->use_count++ == 0)
+	if (substream->use_count == 0) {
+		err = snd_rawmidi_runtime_create(substream);
+		if (err < 0)
+			return err;
+		err = substream->ops->open(substream);
+		if (err < 0)
+			return err;
+		substream->opened = 1;
 		substream->active_sensing = 0;
-	if (mode & SNDRV_RAWMIDI_LFLG_APPEND)
-		substream->append = 1;
+		if (mode & SNDRV_RAWMIDI_LFLG_APPEND)
+			substream->append = 1;
+	}
+	substream->use_count++;
 	rmidi->streams[substream->stream].substream_opened++;
 	return 0;
 }