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>

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;

sound/core/pcm_local.h

@@ -27,6 +27,8 @@ int snd_pcm_hw_constraints_complete(struct snd_pcm_substream *substream);
 int snd_pcm_hw_constraint_mask(struct snd_pcm_runtime *runtime,
 			       snd_pcm_hw_param_t var, u_int32_t mask);
 
+int pcm_lib_apply_appl_ptr(struct snd_pcm_substream *substream,
+			   snd_pcm_uframes_t appl_ptr);
 int snd_pcm_update_state(struct snd_pcm_substream *substream,
 			 struct snd_pcm_runtime *runtime);
 int snd_pcm_update_hw_ptr(struct snd_pcm_substream *substream);

sound/core/pcm_native.c

@@ -2598,27 +2598,6 @@ static int do_pcm_hwsync(struct snd_pcm_substream *substream)
 	}
 }
 
-/* update to the given appl_ptr and call ack callback if needed;
- * when an error is returned, take back to the original value
- */
-static int 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;
-}
-
 /* increase the appl_ptr; returns the processed frames or a negative error */
 static snd_pcm_sframes_t forward_appl_ptr(struct snd_pcm_substream *substream,
 					  snd_pcm_uframes_t frames,
@@ -2635,7 +2614,7 @@ static snd_pcm_sframes_t forward_appl_ptr(struct snd_pcm_substream *substream,
 	appl_ptr = runtime->control->appl_ptr + frames;
 	if (appl_ptr >= (snd_pcm_sframes_t)runtime->boundary)
 		appl_ptr -= runtime->boundary;
-	ret = apply_appl_ptr(substream, appl_ptr);
+	ret = pcm_lib_apply_appl_ptr(substream, appl_ptr);
 	return ret < 0 ? ret : frames;
 }
 
@@ -2655,7 +2634,7 @@ static snd_pcm_sframes_t rewind_appl_ptr(struct snd_pcm_substream *substream,
 	appl_ptr = runtime->control->appl_ptr - frames;
 	if (appl_ptr < 0)
 		appl_ptr += runtime->boundary;
-	ret = apply_appl_ptr(substream, appl_ptr);
+	ret = pcm_lib_apply_appl_ptr(substream, appl_ptr);
 	return ret < 0 ? ret : frames;
 }
 
@@ -2783,7 +2762,8 @@ static int snd_pcm_sync_ptr(struct snd_pcm_substream *substream,
 	}
 	snd_pcm_stream_lock_irq(substream);
 	if (!(sync_ptr.flags & SNDRV_PCM_SYNC_PTR_APPL)) {
-		err = apply_appl_ptr(substream, sync_ptr.c.control.appl_ptr);
+		err = pcm_lib_apply_appl_ptr(substream,
+					     sync_ptr.c.control.appl_ptr);
 		if (err < 0) {
 			snd_pcm_stream_unlock_irq(substream);
 			return err;