Re: [alsa-devel] [PATCH 0/2] ASoC: hdmi-codec: fix locking issue

[Takashi Iwai]

On Wed, 23 Oct 2019 18:12:01 +0200,
Jerome Brunet wrote:
> 
> This patchset fixes the locking issue reported by Russell.
> 
> As explained a mutex was used as flag and held while returning to
> userspace.
> 
> Patch 2 is entirely optional and switches from bit atomic operation
> to mutex again. I tend to prefer bit atomic operation in this
> particular case but either way should be fine.

I fail to see why the mutex is needed there.  Could you elaborate
about the background?

IIUC, the protection with the atomic bitmap should guarantee the
exclusive access.  The mutex would allow the possible concurrent calls
of multiple startup of a single instance, but is this the thing to be
solved?


thanks,

Takashi

> 
> Jerome Brunet (2):
>   Revert "ASoC: hdmi-codec: re-introduce mutex locking"
>   ASoC: hdmi-codec: re-introduce mutex locking again
> 
>  sound/soc/codecs/hdmi-codec.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> -- 
> 2.21.0
> 
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