ASoC: soc-pcm.c: remove indirect runtime copy

substream->runtime will be attached when substream was opened
at snd_pcm_attach_substream(). When it uses DPCM,
FE substream->runtime is attached, but BE substream->runtime is not.
Thus, we are copying FE substream->runtime to BE.

But, we are copyig FE substream->runtime to FE dpcm->runtime first (A),
and copy it to BE dpcm->runtime (B), and copy it to
BE substream->runtime (C).

	static int dpcm_fe_dai_open(...) {
		...
(A)		fe->dpcm[stream].runtime = fe_substream->runtime;
		...
	}

	static int dpcm_be_connect(...) {
		...
(B)		be->dpcm[stream].runtime = fe->dpcm[stream].runtime;
		...
	}

	int dpcm_be_dai_startup(...) {
		...
(C)		be_substream->runtime = be->dpcm[stream].runtime;
		...
	}

It is too roundabout and troublesome.
OTOH, it is directly copying fe_substream->runtime at dpcm_be_reparent()
without using be->dpcm[stream].runtime.

	static void dpcm_be_reparent(...)
	{
		...
		for_each_dpcm_fe(be, stream, dpcm) {
			...
=>			be_substream->runtime = fe_substream->runtime;
			break;
		}
	}

This patch removes indirect copying.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/87v8je64dh.wl-kuninori.morimoto.gx@renesas.com
Signed-off-by: Mark Brown <broonie@kernel.org>

include/sound/soc-dpcm.h

@@ -91,7 +91,6 @@ struct snd_soc_dpcm_runtime {
 	struct list_head fe_clients;
 
 	int users;
-	struct snd_pcm_runtime *runtime;
 	struct snd_pcm_hw_params hw_params;
 
 	/* state and update */

sound/soc/soc-compress.c

@@ -134,8 +134,6 @@ err_no_lock:
 static int soc_compr_open_fe(struct snd_compr_stream *cstream)
 {
 	struct snd_soc_pcm_runtime *fe = cstream->private_data;
-	struct snd_pcm_substream *fe_substream =
-		 fe->pcm->streams[cstream->direction].substream;
 	struct snd_soc_dai *cpu_dai = asoc_rtd_to_cpu(fe, 0);
 	struct snd_soc_dpcm *dpcm;
 	struct snd_soc_dapm_widget_list *list;
@@ -143,7 +141,6 @@ static int soc_compr_open_fe(struct snd_compr_stream *cstream)
 	int ret;
 
 	mutex_lock_nested(&fe->card->mutex, SND_SOC_CARD_CLASS_RUNTIME);
-	fe->dpcm[stream].runtime = fe_substream->runtime;
 
 	ret = dpcm_path_get(fe, stream, &list);
 	if (ret < 0)
@@ -153,7 +150,6 @@ static int soc_compr_open_fe(struct snd_compr_stream *cstream)
 
 	/* calculate valid and active FE <-> BE dpcms */
 	dpcm_process_paths(fe, stream, &list, 1);
-	fe->dpcm[stream].runtime = fe_substream->runtime;
 
 	fe->dpcm[stream].runtime_update = SND_SOC_DPCM_UPDATE_FE;
 
@@ -164,7 +160,6 @@ static int soc_compr_open_fe(struct snd_compr_stream *cstream)
 			dpcm->state = SND_SOC_DPCM_LINK_STATE_FREE;
 
 		dpcm_be_disconnect(fe, stream);
-		fe->dpcm[stream].runtime = NULL;
 		goto out;
 	}
 
@@ -236,8 +231,6 @@ static int soc_compr_free_fe(struct snd_compr_stream *cstream)
 
 	mutex_unlock(&fe->card->pcm_mutex);
 
-	fe->dpcm[stream].runtime = NULL;
-
 	snd_soc_link_compr_shutdown(cstream, 0);
 
 	snd_soc_compr_components_free(cstream, 0);

sound/soc/soc-pcm.c

@@ -1230,7 +1230,6 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 
 	dpcm->be = be;
 	dpcm->fe = fe;
-	be->dpcm[stream].runtime = fe->dpcm[stream].runtime;
 	dpcm->state = SND_SOC_DPCM_LINK_STATE_NEW;
 	snd_soc_dpcm_stream_lock_irq(fe, stream);
 	list_add(&dpcm->list_be, &fe->dpcm[stream].be_clients);
@@ -1465,10 +1464,11 @@ static int dpcm_add_paths(struct snd_soc_pcm_runtime *fe, int stream,
 	struct snd_soc_dapm_widget_list *list = *list_;
 	struct snd_soc_pcm_runtime *be;
 	struct snd_soc_dapm_widget *widget;
+	struct snd_pcm_substream *fe_substream = snd_soc_dpcm_get_substream(fe, stream);
 	int i, new = 0, err;
 
 	/* don't connect if FE is not running */
-	if (!fe->dpcm[stream].runtime && !fe->fe_compr)
+	if (!fe_substream->runtime && !fe->fe_compr)
 		return new;
 
 	/* Create any new FE <--> BE connections */
@@ -1590,6 +1590,7 @@ void dpcm_be_dai_stop(struct snd_soc_pcm_runtime *fe, int stream,
 
 int dpcm_be_dai_startup(struct snd_soc_pcm_runtime *fe, int stream)
 {
+	struct snd_pcm_substream *fe_substream = snd_soc_dpcm_get_substream(fe, stream);
 	struct snd_soc_pcm_runtime *be;
 	struct snd_soc_dpcm *dpcm;
 	int err, count = 0;
@@ -1629,7 +1630,7 @@ int dpcm_be_dai_startup(struct snd_soc_pcm_runtime *fe, int stream)
 		dev_dbg(be->dev, "ASoC: open %s BE %s\n",
 			stream ? "capture" : "playback", be->dai_link->name);
 
-		be_substream->runtime = be->dpcm[stream].runtime;
+		be_substream->runtime = fe_substream->runtime;
 		err = __soc_pcm_open(be, be_substream);
 		if (err < 0) {
 			be->dpcm[stream].users--;
@@ -2693,8 +2694,6 @@ static void dpcm_fe_dai_cleanup(struct snd_pcm_substream *fe_substream)
 		dpcm->state = SND_SOC_DPCM_LINK_STATE_FREE;
 
 	dpcm_be_disconnect(fe, stream);
-
-	fe->dpcm[stream].runtime = NULL;
 }
 
 static int dpcm_fe_dai_close(struct snd_pcm_substream *fe_substream)
@@ -2719,7 +2718,6 @@ static int dpcm_fe_dai_open(struct snd_pcm_substream *fe_substream)
 	int stream = fe_substream->stream;
 
 	snd_soc_dpcm_mutex_lock(fe);
-	fe->dpcm[stream].runtime = fe_substream->runtime;
 
 	ret = dpcm_path_get(fe, stream, &list);
 	if (ret < 0)