linux-kernel - Re: [PATCH v10 2/3] interconnect: qcom: Add MSM8916 interconnect provider driver

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Date:   Wed, 13 Nov 2019 15:24:19 +0200
From:   Georgi Djakov <georgi.djakov@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>, robh+dt@...nel.org,
        linux-pm@...r.kernel.org
Cc:     agross@...nel.org, bjorn.andersson@...aro.org,
        evgreen@...omium.org, daidavid1@...eaurora.org,
        vincent.guittot@...aro.org, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v10 2/3] interconnect: qcom: Add MSM8916 interconnect
 provider driver

Hi Dmitry,

On 13.11.19 г. 15:03 ч., Dmitry Osipenko wrote:
> 30.10.2019 18:39, Georgi Djakov пишет:
>> Add driver for the Qualcomm interconnect buses found in MSM8916 based
>> platforms. The topology consists of three NoCs that are controlled by
>> a remote processor that collects the aggregated bandwidth for each
>> master-slave pairs.
>>
[..]
>> +static int qnoc_remove(struct platform_device *pdev)
>> +{
>> +	struct qcom_icc_provider *qp = platform_get_drvdata(pdev);
>> +	struct icc_provider *provider = &qp->provider;
>> +	struct icc_node *n;
>> +
>> +	list_for_each_entry(n, &provider->nodes, node_list) {
>> +		icc_node_del(n);
>> +		icc_node_destroy(n->id);
>> +	}
> 
> Hello Georgi,
> 
> While examining the interconnect API and current drivers' code, I
> noticed that everybody are copying this chunk of code which should crash
> kernel because removing node from a list during the traverse is allowed
> only when list_for_each_entry_safe() is used.

Nice catch. Thank you!

> Seems the IMX driver (which is under review now on the ML) is the only
> driver that does the removing procedure correctly.
> 
> Maybe it won't hurt to factor out the removal of provider's nodes into a
> common helper.
> 

Yes, this is a very good idea. Will do it.

Thanks,
Georgi