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ASoC: soc-pcm: Fix DPCM lockdep warning due to nested stream locks 

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: b2ae806630 ("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@samsung.com
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>
This commit is contained in:
Takashi Iwai 2022-01-19 16:52:48 +01:00 committed by Mark Brown
parent fb25621da5
commit 3c75c0ea5d
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
3 changed files with 31 additions and 3 deletions
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15
include/sound/pcm.h
View File

@ -614,6 +614,7 @@ void snd_pcm_stream_unlock(struct snd_pcm_substream *substream);
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
@ -632,6 +633,20 @@ unsigned long _snd_pcm_stream_lock_irqsave(struct snd_pcm_substream *substream);
void snd_pcm_stream_unlock_irqrestore(struct snd_pcm_substream *substream,
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

13
sound/core/pcm_native.c
View File

@ -172,6 +172,19 @@ unsigned long _snd_pcm_stream_lock_irqsave(struct snd_pcm_substream *substream)
}
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

6
sound/soc/soc-pcm.c
View File

@ -46,8 +46,8 @@ static inline void snd_soc_dpcm_stream_lock_irq(struct snd_soc_pcm_runtime *rtd,
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)
@ -2094,7 +2094,7 @@ int dpcm_be_dai_trigger(struct snd_soc_pcm_runtime *fe, int stream,
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))