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Date:   Fri, 2 Aug 2019 23:07:32 +0530
From:   Vinod Koul <vkoul@kernel.org>
To:     Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc:     alsa-devel@alsa-project.org, tiwai@suse.de,
        gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        broonie@kernel.org, srinivas.kandagatla@linaro.org,
        jank@cadence.com, slawomir.blauciak@intel.com,
        Sanyog Kale <sanyog.r.kale@intel.com>
Subject: Re: [alsa-devel] [RFC PATCH 06/40] soundwire: intel: prevent
 possible dereference in hw_params
Message-ID: <20190802173732.GF12733@vkoul-mobl.Dlink>
References: <20190725234032.21152-1-pierre-louis.bossart@linux.intel.com>
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 <20190802115537.GI12733@vkoul-mobl.Dlink>
 <6da5aeef-40bf-c9bb-fc18-4ac0b3961857@linux.intel.com>
 <20190802155738.GR12733@vkoul-mobl.Dlink>
 <884a13fc-08eb-10c9-de9c-50cf38ff533d@linux.intel.com>
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On 02-08-19, 11:52, Pierre-Louis Bossart wrote:
> 
> 
> On 8/2/19 10:57 AM, Vinod Koul wrote:
> > On 02-08-19, 10:16, Pierre-Louis Bossart wrote:
> > > 
> > > 
> > > On 8/2/19 6:55 AM, Vinod Koul wrote:
> > > > On 25-07-19, 18:39, Pierre-Louis Bossart wrote:
> > > > > This should not happen in production systems but we should test for
> > > > > all callback arguments before invoking the config_stream callback.
> > > > 
> > > > so you are saying callback arg is mandatory, if so please document that
> > > > assumption
> > > 
> > > no, what this says is that if a config_stream is provided then it needs to
> > > have a valid argument.
> > 
> > well typically args are not mandatory..
> > 
> > > I am not sure what you mean by "document that assumption", comment in the
> > > code (where?) or SoundWire documentation?
> > 
> > The callback documentation which in this is in include/linux/soundwire/sdw_intel.h
> > 
> 
> /**
>  * struct sdw_intel_ops: Intel audio driver callback ops
>  *
>  * @config_stream: configure the stream with the hw_params
>  */
> struct sdw_intel_ops {
> 	int (*config_stream)(void *arg, void *substream,
> 			     void *dai, void *hw_params, int stream_num);
> };
> 
> all parameters are mandatory really, not sure what you are trying to get at.

It would be good to make a note that argument is mandatory!

Thanks
-- 
~Vinod