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

[Peter Rosin]

On 2016-09-21 09:56, Alexander Shiyan wrote:
>> Среда, 21 сентября 2016, 9:57 +03:00 от Yangbo Lu :
>>
>> From: Arnd Bergmann < a...@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(_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

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

[Peter Rosin]

On 2016-09-21 09:56, Alexander Shiyan wrote:
>> Среда, 21 сентября 2016, 9:57 +03:00 от Yangbo Lu :
>>
>> From: Arnd Bergmann < a...@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(_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

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

[Alexander Shiyan]

>Среда, 21 сентября 2016, 9:57 +03:00 от Yangbo Lu :
>
>From: Arnd Bergmann < a...@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(_bus_type, NULL, (void *)matches,
>+   soc_device_match_one);
>+if (!ret)
>+matches++;

So, what happen if next "matches" (after increment) will be NULL?

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

---

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

[Alexander Shiyan]

>Среда, 21 сентября 2016, 9:57 +03:00 от Yangbo Lu :
>
>From: Arnd Bergmann < a...@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(_bus_type, NULL, (void *)matches,
>+   soc_device_match_one);
>+if (!ret)
>+matches++;

So, what happen if next "matches" (after increment) will be NULL?

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

---