Message-ID: <5821a8bb-8751-70e8-970f-eb2bf2b077fb@linaro.org>
Date:   Mon, 6 Feb 2023 08:00:46 -0600
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Subject: Re: [PATCH v9 08/27] mailbox: Add Gunyah message queue mailbox
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To:     Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Elliot Berman <quic_eberman@quicinc.com>,
        Bjorn Andersson <quic_bjorande@quicinc.com>,
        Murali Nalajala <quic_mnalajal@quicinc.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Jassi Brar <jassisinghbrar@gmail.com>
Cc:     Trilok Soni <quic_tsoni@quicinc.com>,
        Srivatsa Vaddagiri <quic_svaddagi@quicinc.com>,
        Carl van Schaik <quic_cvanscha@quicinc.com>,
        Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Bagas Sanjaya <bagasdotme@gmail.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
        Sudeep Holla <sudeep.holla@arm.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: <20230120224627.4053418-1-quic_eberman@quicinc.com>
 <20230120224627.4053418-9-quic_eberman@quicinc.com>
 <e5acd00c-7a53-a789-8dab-a69cffda34f5@linaro.org>
From:   Alex Elder <elder@linaro.org>
In-Reply-To: <e5acd00c-7a53-a789-8dab-a69cffda34f5@linaro.org>
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On 2/2/23 3:59 AM, Srinivas Kandagatla wrote:
>>
>> +static irqreturn_t gh_msgq_rx_irq_handler(int irq, void *data)
>> +{
>> +    struct gh_msgq *msgq = data;
>> +    struct gh_msgq_rx_data rx_data;
>> +    unsigned long gh_err;
>> +    bool ready = true;
>> +
>> +    while (ready) {
>> +        gh_err = gh_hypercall_msgq_recv(msgq->rx_ghrsc->capid,
>> +                (uintptr_t)&rx_data.data, sizeof(rx_data.data),
> you should proabably use  GH_MSGQ_MAX_MSG_SIZE instead of calling sizeof 
> for every loop.

I disagree with this comment.

I think sizeof(object) conveys more meaning that CONSTANT_SIZE,
and both values are known at compile time (so there is no cost
of "calling sizeof" a lot.

					-Alex

> 
>> +                &rx_data.length, &ready);
>> +        if (gh_err == GH_ERROR_OK) {
>> +            mbox_chan_received_data(gh_msgq_chan(msgq), &rx_data);
>> +        } else if (gh_err == GH_ERROR_MSGQUEUE_EMPTY) {
>> +            break;
>> +        } else {
>> +            pr_warn("Failed to receive data from msgq for %s: %zd\n",
>> +                msgq->mbox.dev ? dev_name(msgq->mbox.dev) : "", gh_err);
>> +            break;
>> +        }
>> +    }
>> +
>> +    return IRQ_HANDLED;
>> +}