diff mbox series

[v2] ASoC: soc-pcm: Shrink stack frame for __soc_pcm_hw_params

Message ID 20230908085920.2906359-1-ckeepax@opensource.cirrus.com (mailing list archive)
State Accepted
Commit 396b907919e028d89bac912e49de014485deb8dc
Headers show
Series [v2] ASoC: soc-pcm: Shrink stack frame for __soc_pcm_hw_params | expand

Commit Message

Charles Keepax Sept. 8, 2023, 8:59 a.m. UTC 
Commit ac950278b087 ("ASoC: add N cpus to M codecs dai link support")
added an additional local params in __soc_pcm_hw_params, for the CPU
side of the DAI. The snd_pcm_hw_params struct is pretty large (604
bytes) and keeping two local copies of it can make the stack frame
really large.

It is worth noting the variables are in separate code blocks so for
some optimisation levels in the compiler these will get automatically
combined keeping the stack frame reasonable. But better to manually
combine them to cover all cases.

Add a single local variable for __soc_pcm_hw_params and use in both
loops to shrink the stack frame.

Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v1:
 - Expand commit message to not that some compiler optimisations also
   shrink the stack frame.

 sound/soc/soc-pcm.c | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

Comments

Mark Brown Sept. 11, 2023, 3:07 p.m. UTC | #1 
On Fri, 08 Sep 2023 09:59:20 +0100, Charles Keepax wrote:
> Commit ac950278b087 ("ASoC: add N cpus to M codecs dai link support")
> added an additional local params in __soc_pcm_hw_params, for the CPU
> side of the DAI. The snd_pcm_hw_params struct is pretty large (604
> bytes) and keeping two local copies of it can make the stack frame
> really large.
> 
> It is worth noting the variables are in separate code blocks so for
> some optimisation levels in the compiler these will get automatically
> combined keeping the stack frame reasonable. But better to manually
> combine them to cover all cases.
> 
> [...]

Applied to

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-next

Thanks!

[1/1] ASoC: soc-pcm: Shrink stack frame for __soc_pcm_hw_params
      commit: 396b907919e028d89bac912e49de014485deb8dc

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark
diff mbox series

Patch

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index 3aa6b988cb4b4..46917add10560 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -985,6 +985,7 @@  static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd,
 {
 	struct snd_soc_dai *cpu_dai;
 	struct snd_soc_dai *codec_dai;
+	struct snd_pcm_hw_params tmp_params;
 	int i, ret = 0;
 
 	snd_soc_dpcm_mutex_assert_held(rtd);
@@ -998,7 +999,6 @@  static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd,
 		goto out;
 
 	for_each_rtd_codec_dais(rtd, i, codec_dai) {
-		struct snd_pcm_hw_params codec_params;
 		unsigned int tdm_mask = snd_soc_dai_tdm_mask_get(codec_dai, substream->stream);
 
 		/*
@@ -1019,23 +1019,22 @@  static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd,
 			continue;
 
 		/* copy params for each codec */
-		codec_params = *params;
+		tmp_params = *params;
 
 		/* fixup params based on TDM slot masks */
 		if (tdm_mask)
-			soc_pcm_codec_params_fixup(&codec_params, tdm_mask);
+			soc_pcm_codec_params_fixup(&tmp_params, tdm_mask);
 
 		ret = snd_soc_dai_hw_params(codec_dai, substream,
-					    &codec_params);
+					    &tmp_params);
 		if(ret < 0)
 			goto out;
 
-		soc_pcm_set_dai_params(codec_dai, &codec_params);
-		snd_soc_dapm_update_dai(substream, &codec_params, codec_dai);
+		soc_pcm_set_dai_params(codec_dai, &tmp_params);
+		snd_soc_dapm_update_dai(substream, &tmp_params, codec_dai);
 	}
 
 	for_each_rtd_cpu_dais(rtd, i, cpu_dai) {
-		struct snd_pcm_hw_params cpu_params;
 		unsigned int ch_mask = 0;
 		int j;
 
@@ -1047,7 +1046,7 @@  static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd,
 			continue;
 
 		/* copy params for each cpu */
-		cpu_params = *params;
+		tmp_params = *params;
 
 		if (!rtd->dai_link->codec_ch_maps)
 			goto hw_params;
@@ -1062,16 +1061,16 @@  static int __soc_pcm_hw_params(struct snd_soc_pcm_runtime *rtd,
 
 		/* fixup cpu channel number */
 		if (ch_mask)
-			soc_pcm_codec_params_fixup(&cpu_params, ch_mask);
+			soc_pcm_codec_params_fixup(&tmp_params, ch_mask);
 
 hw_params:
-		ret = snd_soc_dai_hw_params(cpu_dai, substream, &cpu_params);
+		ret = snd_soc_dai_hw_params(cpu_dai, substream, &tmp_params);
 		if (ret < 0)
 			goto out;
 
 		/* store the parameters for each DAI */
-		soc_pcm_set_dai_params(cpu_dai, &cpu_params);
-		snd_soc_dapm_update_dai(substream, &cpu_params, cpu_dai);
+		soc_pcm_set_dai_params(cpu_dai, &tmp_params);
+		snd_soc_dapm_update_dai(substream, &tmp_params, cpu_dai);
 	}
 
 	ret = snd_soc_pcm_component_hw_params(substream, params);