ALSA: pcm: unify codes to operate application-side position on PCM buffer

In a series of recent work, ALSA PCM core got some arrangements to handle
application-side position on PCM buffer. However, relevant codes still
disperse to two translation units

This commit unifies these codes into a helper function.

Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 24 insertions, 3 deletions

diff --git a/sound/core/pcm_lib.c b/sound/core/pcm_lib.c
index 9dc7bbfe8853..d82f1437667f 100644
--- a/sound/core/pcm_lib.c
+++ b/sound/core/pcm_lib.c
@@ -2101,6 +2101,27 @@ static int pcm_accessible_state(struct snd_pcm_runtime *runtime)
 	}
 }
 
+/* update to the given appl_ptr and call ack callback if needed;
+ * when an error is returned, take back to the original value
+ */
+int pcm_lib_apply_appl_ptr(struct snd_pcm_substream *substream,
+			   snd_pcm_uframes_t appl_ptr)
+{
+	struct snd_pcm_runtime *runtime = substream->runtime;
+	snd_pcm_uframes_t old_appl_ptr = runtime->control->appl_ptr;
+	int ret;
+
+	runtime->control->appl_ptr = appl_ptr;
+	if (substream->ops->ack) {
+		ret = substream->ops->ack(substream);
+		if (ret < 0) {
+			runtime->control->appl_ptr = old_appl_ptr;
+			return ret;
+		}
+	}
+	return 0;
+}
+
 /* the common loop for read/write data */
 snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
 				     void *data, bool interleaved,
@@ -2220,9 +2241,9 @@ snd_pcm_sframes_t __snd_pcm_lib_xfer(struct snd_pcm_substream *substream,
 		appl_ptr += frames;
 		if (appl_ptr >= runtime->boundary)
 			appl_ptr -= runtime->boundary;
-		runtime->control->appl_ptr = appl_ptr;
-		if (substream->ops->ack)
-			substream->ops->ack(substream);
+		err = pcm_lib_apply_appl_ptr(substream, appl_ptr);
+		if (err < 0)
+			goto _end_unlock;
 
 		offset += frames;
 		size -= frames;