Re: [v12, 7/8] base: soc: introduce soc_device_match() interface

From: Peter Rosin <peda@axentia.se>
To: Alexander Shiyan <shc_work@mail.ru>, Yangbo Lu <yangbo.lu@nxp.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	ulf.hansson@linaro.org, Xiaobo Xie <xiaobo.xie@nxp.com>,
	Minghuan Lian <minghuan.lian@nxp.com>,
	linux-i2c@vger.kernel.org, linux-clk@vger.kernel.org,
	Qiang Zhao <qiang.zhao@nxp.com>,
	Russell King <linux@arm.linux.org.uk>,
	Bhupesh Sharma <bhupesh.sharma@freescale.com>,
	Joerg Roedel <joro@8bytes.org>,
	Jochen Friedrich <jochen@scram.de>,
	Claudiu Manoil <claudiu.manoil@freescale.com>,
	devicetree@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	Scott Wood <oss@buserror.net>, Rob Herring <robh+dt@kernel.org>,
	Santosh Shilimkar <ssantosh@kernel.org>,
	linux-arm-kernel@lists.infradead.org, netdev@vger.kernel.org,
	linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
	Leo Li <leoyang.li@nxp.com>,
	iommu@lists.linux-foundation.org,
	Kumar Gala <galak@codeaurora.org>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [v12, 7/8] base: soc: introduce soc_device_match() interface
Date: Wed, 21 Sep 2016 10:25:08 +0200	[thread overview]
Message-ID: <aa53da4f-205d-cfa1-c85c-00e82e928bbc@axentia.se> (raw)
In-Reply-To: <1474444574.270880035@f136.i.mail.ru>

On 2016-09-21 09:56, Alexander Shiyan wrote:
>> Среда, 21 сентября 2016, 9:57 +03:00 от Yangbo Lu <yangbo.lu@nxp.com>:
>>
>> From: Arnd Bergmann < arnd@arndb.de >
>>
>> We keep running into cases where device drivers want to know the exact
>> version of the a SoC they are currently running on. In the past, this has
>> usually been done through a vendor specific API that can be called by a
>> driver, or by directly accessing some kind of version register that is
>> not part of the device itself but that belongs to a global register area
>> of the chip.
> ...
>> +const struct soc_device_attribute *soc_device_match(
>> +const struct soc_device_attribute *matches)
>> +{
>> +int ret = 0;
>> +
>> +if (!matches)
>> +return NULL;
>> +
>> +while (!ret) {
>> +if (!(matches->machine || matches->family ||
>> +      matches->revision || matches->soc_id))
>> +break;
>> +ret = bus_for_each_dev(&soc_bus_type, NULL, (void *)matches,
>> +       soc_device_match_one);
>> +if (!ret)
>> +matches++;
> 
> So, what happen if next "matches" (after increment) will be NULL?

A crash?

> I think you should use while(matches) at the start of this procedure.

*arrgh*

*If* matches wrap, you indeed have *big* problems. *Elsewhere*

Hint: Please read the review comments on the previous version of this
series [1] before commenting further.

Cheers,
Peter

[1] https://www.mail-archive.com/netdev@vger.kernel.org/msg126617.html

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