Re: [alsa-devel] [PATCH] ASoC: dmaengine: Make the pcm->name equal to pcm->id if the name is not set

From: Takashi Iwai <tiwai@suse.de>
To: Peter Ujfalusi <peter.ujfalusi@ti.com>
Cc: alsa-devel@alsa-project.org, broonie@kernel.org,
	lgirdwood@gmail.com, arthur.she@linaro.org
Subject: Re: [alsa-devel] [PATCH] ASoC: dmaengine: Make the pcm->name equal to	pcm->id if the name is not set
Date: Tue, 10 Sep 2019 14:07:21 +0200	[thread overview]
Message-ID: <s5hblvs8idi.wl-tiwai@suse.de> (raw)
In-Reply-To: <20190906055524.7393-1-peter.ujfalusi@ti.com>

On Fri, 06 Sep 2019 07:55:24 +0200,
Peter Ujfalusi wrote:
> 
> Some tools use the snd_pcm_info_get_name() to try to identify PCMs or for
> other purposes.
> 
> Currently it is left empty with the dmaengine-pcm, in this case copy the
> pcm->id string as pcm->name.
> 
> For example IGT is using this to find the HDMI PCM for testing audio on it.
> 
> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
> Reported-by: Arthur She <arthur.she@linaro.org>
> ---
> Hi,
> 
> this was actually reported for 4.14 kernel with omap-pcm (replaced by sdma-pcm
> in v4.18), since then we only use the generic dmaengine PCM but the same issue
> applies today.
> 
> Regards,
> Peter
> 
>  sound/soc/soc-generic-dmaengine-pcm.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/sound/soc/soc-generic-dmaengine-pcm.c b/sound/soc/soc-generic-dmaengine-pcm.c
> index 748f5f641002..d93db2c2b527 100644
> --- a/sound/soc/soc-generic-dmaengine-pcm.c
> +++ b/sound/soc/soc-generic-dmaengine-pcm.c
> @@ -306,6 +306,12 @@ static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
>  
>  		if (!dmaengine_pcm_can_report_residue(dev, pcm->chan[i]))
>  			pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE;
> +
> +		if (rtd->pcm->streams[i].pcm->name[0] == '\0') {
> +			strncpy(rtd->pcm->streams[i].pcm->name,
> +				rtd->pcm->streams[i].pcm->id,
> +				sizeof(rtd->pcm->streams[i].pcm->name));
> +		}

Any reason to use strncpy() instead of strscpy()?
After merging Mark's branch, I got a compile warning like:
  sound/soc/soc-generic-dmaengine-pcm.c:311:4: warning: 'strncpy'
  accessing 80 bytes at offsets 88 and 24 may overlap up to 0 bytes at
  offset [9223372036854775807, -9223372036854775808] [-Wrestrict]

Takashi

>  
>  	return 0;
> -- 
> Peter
> 
> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
> 
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