Message-ID: <b04aef26-ee0d-af01-3aa1-a0c77d9cbaf3@quicinc.com>
Date:   Thu, 16 Feb 2023 09:40:52 -0800
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Subject: Re: [PATCH v10 08/26] gunyah: rsc_mgr: Add resource manager RPC core
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To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC:     Alex Elder <elder@linaro.org>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>,
        Murali Nalajala <quic_mnalajal@quicinc.com>,
        Trilok Soni <quic_tsoni@quicinc.com>,
        Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>,
        Carl van Schaik <quic_cvanscha@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        "Arnd Bergmann" <arnd@arndb.de>, Rob Herring <robh+dt@kernel.org>,
        "Krzysztof Kozlowski" <krzysztof.kozlowski+dt@linaro.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Jassi Brar <jassisinghbrar@gmail.com>,
        <linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <linux-doc@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>
References: <20230214211229.3239350-1-quic_eberman@quicinc.com>
 <20230214212327.3310128-1-quic_eberman@quicinc.com>
 <Y+3QqdQVH5BTbnaP@kroah.com>
From:   Elliot Berman <quic_eberman@quicinc.com>
In-Reply-To: <Y+3QqdQVH5BTbnaP@kroah.com>
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On 2/15/2023 10:43 PM, Greg Kroah-Hartman wrote:
> On Tue, Feb 14, 2023 at 01:23:25PM -0800, Elliot Berman wrote:
>> +struct gh_rm {
>> +	struct device *dev;
> 
> What device does this point to?
> 

The platform device.

>> +	struct gunyah_resource tx_ghrsc, rx_ghrsc;
>> +	struct gh_msgq msgq;
>> +	struct mbox_client msgq_client;
>> +	struct gh_rm_connection *active_rx_connection;
>> +	int last_tx_ret;
>> +
>> +	struct idr call_idr;
>> +	struct mutex call_idr_lock;
>> +
>> +	struct kmem_cache *cache;
>> +	struct mutex send_lock;
>> +	struct blocking_notifier_head nh;
>> +};
> 
> This obviously is the "device" that your system works on, so what are
> the lifetime rules of it?  Why isn't is just a real 'struct device' in
> the system instead of a random memory blob with a pointer to a device?
> 
> What controls the lifetime of this structure and where is the reference
> counting logic for it?
> 

The lifetime of the structure is bound by the platform device that above 
struct device *dev points to. get_gh_rm and put_gh_rm increments the 
device ref counter and ensures lifetime of the struct is also extended.

> And why no documentation for this core structure?
> 

Sure, I will add.

> thanks,
> 
> greg k-h