Patch "ASoC: soc-pcm: align BE 'atomicity' with that of the FE" has been added to the 5.15-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ASoC: soc-pcm: align BE 'atomicity' with that of the FE

to the 5.15-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     asoc-soc-pcm-align-be-atomicity-with-that-of-the-fe.patch
and it can be found in the queue-5.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 15b0d8aaea3eee8dcd37352d6bbb3effdb269bf3
Author: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
Date:   Tue Dec 7 11:37:41 2021 -0600

    ASoC: soc-pcm: align BE 'atomicity' with that of the FE
    
    [ Upstream commit bbf7d3b1c4f40eb02dd1dffb500ba00b0bff0303 ]
    
    Since the flow for DPCM is based on taking a lock for the FE first, we
    need to make sure during the connection between a BE and an FE that
    they both use the same 'atomicity', otherwise we may sleep in atomic
    context.
    
    If the FE is nonatomic, this patch forces the BE to be nonatomic as
    well. That should have no negative impact since the BE 'inherits' the
    FE properties.
    
    However, if the FE is atomic and the BE is not, then the configuration
    is flagged as invalid.
    
    Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
    [ removed FE stream lock by tiwai ]
    Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
    Reviewed-by: Kai Vehmanen <kai.vehmanen@xxxxxxxxxxxxxxx>
    Reviewed-by: Bard Liao <yung-chuan.liao@xxxxxxxxxxxxxxx>
    Reviewed-by: Ranjani Sridharan <ranjani.sridharan@xxxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20211207173745.15850-3-pierre-louis.bossart@xxxxxxxxxxxxxxx
    Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/sound/soc/soc-pcm.c b/sound/soc/soc-pcm.c
index a2b20526e7e2b..7bea8fa59f676 100644
--- a/sound/soc/soc-pcm.c
+++ b/sound/soc/soc-pcm.c
@@ -1123,6 +1123,8 @@ static snd_pcm_uframes_t soc_pcm_pointer(struct snd_pcm_substream *substream)
 static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 		struct snd_soc_pcm_runtime *be, int stream)
 {
+	struct snd_pcm_substream *fe_substream;
+	struct snd_pcm_substream *be_substream;
 	struct snd_soc_dpcm *dpcm;
 	unsigned long flags;
 
@@ -1132,6 +1134,20 @@ static int dpcm_be_connect(struct snd_soc_pcm_runtime *fe,
 			return 0;
 	}
 
+	fe_substream = snd_soc_dpcm_get_substream(fe, stream);
+	be_substream = snd_soc_dpcm_get_substream(be, stream);
+
+	if (!fe_substream->pcm->nonatomic && be_substream->pcm->nonatomic) {
+		dev_err(be->dev, "%s: FE is atomic but BE is nonatomic, invalid configuration\n",
+			__func__);
+		return -EINVAL;
+	}
+	if (fe_substream->pcm->nonatomic && !be_substream->pcm->nonatomic) {
+		dev_warn(be->dev, "%s: FE is nonatomic but BE is not, forcing BE as nonatomic\n",
+			 __func__);
+		be_substream->pcm->nonatomic = 1;
+	}
+
 	dpcm = kzalloc(sizeof(struct snd_soc_dpcm), GFP_ATOMIC);
 	if (!dpcm)
 		return -ENOMEM;