From: Takashi Iwai tiwai@suse.de
commit 3c75c0ea5da749bd1efebd1387f2e5011b8c7d78 upstream.
The recent change for DPCM locking caused spurious lockdep warnings. Actually the warnings are false-positive, as those are triggered due to the nested stream locks for FE and BE. Since both locks belong to the same lock class, lockdep sees it as if a deadlock.
For fixing this, we need to take PCM stream locks for BE with the nested lock primitives. Since currently snd_pcm_stream_lock*() helper assumes only the top-level single locking, a new helper function snd_pcm_stream_lock_irqsave_nested() is defined for a single-depth nested lock, which is now used in the BE DAI trigger that is always performed inside a FE stream lock.
Fixes: b2ae80663008 ("ASoC: soc-pcm: serialize BE triggers") Reported-and-tested-by: Hans de Goede hdegoede@redhat.com Reported-and-tested-by: Marek Szyprowski m.szyprowski@samsung.com Link: https://lore.kernel.org/r/73018f3c-9769-72ea-0325-b3f8e2381e30@redhat.com Link: https://lore.kernel.org/alsa-devel/9a0abddd-49e9-872d-2f00-a1697340f786@sams... Signed-off-by: Takashi Iwai tiwai@suse.de Link: https://lore.kernel.org/r/20220119155249.26754-2-tiwai@suse.de Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- include/sound/pcm.h | 15 +++++++++++++++ sound/core/pcm_native.c | 13 +++++++++++++ sound/soc/soc-pcm.c | 6 +++--- 3 files changed, 31 insertions(+), 3 deletions(-)
--- a/include/sound/pcm.h +++ b/include/sound/pcm.h @@ -616,6 +616,7 @@ void snd_pcm_stream_unlock(struct snd_pc void snd_pcm_stream_lock_irq(struct snd_pcm_substream *substream); void snd_pcm_stream_unlock_irq(struct snd_pcm_substream *substream); unsigned long _snd_pcm_stream_lock_irqsave(struct snd_pcm_substream *substream); +unsigned long _snd_pcm_stream_lock_irqsave_nested(struct snd_pcm_substream *substream);
/** * snd_pcm_stream_lock_irqsave - Lock the PCM stream @@ -635,6 +636,20 @@ void snd_pcm_stream_unlock_irqrestore(st unsigned long flags);
/** + * snd_pcm_stream_lock_irqsave_nested - Single-nested PCM stream locking + * @substream: PCM substream + * @flags: irq flags + * + * This locks the PCM stream like snd_pcm_stream_lock_irqsave() but with + * the single-depth lockdep subclass. + */ +#define snd_pcm_stream_lock_irqsave_nested(substream, flags) \ + do { \ + typecheck(unsigned long, flags); \ + flags = _snd_pcm_stream_lock_irqsave_nested(substream); \ + } while (0) + +/** * snd_pcm_group_for_each_entry - iterate over the linked substreams * @s: the iterator * @substream: the substream --- a/sound/core/pcm_native.c +++ b/sound/core/pcm_native.c @@ -172,6 +172,19 @@ unsigned long _snd_pcm_stream_lock_irqsa } EXPORT_SYMBOL_GPL(_snd_pcm_stream_lock_irqsave);
+unsigned long _snd_pcm_stream_lock_irqsave_nested(struct snd_pcm_substream *substream) +{ + unsigned long flags = 0; + if (substream->pcm->nonatomic) + mutex_lock_nested(&substream->self_group.mutex, + SINGLE_DEPTH_NESTING); + else + spin_lock_irqsave_nested(&substream->self_group.lock, flags, + SINGLE_DEPTH_NESTING); + return flags; +} +EXPORT_SYMBOL_GPL(_snd_pcm_stream_lock_irqsave_nested); + /** * snd_pcm_stream_unlock_irqrestore - Unlock the PCM stream * @substream: PCM substream --- a/sound/soc/soc-pcm.c +++ b/sound/soc/soc-pcm.c @@ -46,8 +46,8 @@ static inline void snd_soc_dpcm_stream_l snd_pcm_stream_lock_irq(snd_soc_dpcm_get_substream(rtd, stream)); }
-#define snd_soc_dpcm_stream_lock_irqsave(rtd, stream, flags) \ - snd_pcm_stream_lock_irqsave(snd_soc_dpcm_get_substream(rtd, stream), flags) +#define snd_soc_dpcm_stream_lock_irqsave_nested(rtd, stream, flags) \ + snd_pcm_stream_lock_irqsave_nested(snd_soc_dpcm_get_substream(rtd, stream), flags)
static inline void snd_soc_dpcm_stream_unlock_irq(struct snd_soc_pcm_runtime *rtd, int stream) @@ -2109,7 +2109,7 @@ int dpcm_be_dai_trigger(struct snd_soc_p be = dpcm->be; be_substream = snd_soc_dpcm_get_substream(be, stream);
- snd_soc_dpcm_stream_lock_irqsave(be, stream, flags); + snd_soc_dpcm_stream_lock_irqsave_nested(be, stream, flags);
/* is this op for this BE ? */ if (!snd_soc_dpcm_be_can_update(fe, be, stream))