Christophe Leroy <christophe.le...@csgroup.eu> writes:
> Le 04/03/2022 à 15:26, Marc Zyngier a écrit :
>> On Fri, 04 Mar 2022 13:10:19 +0000,
>> Christophe Leroy <christophe.le...@csgroup.eu> wrote:
>>> Le 04/03/2022 à 02:18, cgel....@gmail.com a écrit :
>>>> From: Minghao Chi (CGEL ZTE) <chi.ming...@zte.com.cn>
>>>>
>>>> Use of_device_get_match_data() to simplify the code.
>>>>
>>>> Reported-by: Zeal Robot <zea...@zte.com.cn>
>>>> Signed-off-by: Minghao Chi (CGEL ZTE) <chi.ming...@zte.com.cn>
>>>> ---
>>>> arch/powerpc/sysdev/fsl_msi.c | 6 +-----
>>>> 1 file changed, 1 insertion(+), 5 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/sysdev/fsl_msi.c b/arch/powerpc/sysdev/fsl_msi.c
>>>> index b3475ae9f236..9d135bbb30b7 100644
>>>> --- a/arch/powerpc/sysdev/fsl_msi.c
>>>> +++ b/arch/powerpc/sysdev/fsl_msi.c
>>>> @@ -387,7 +387,6 @@ static int fsl_msi_setup_hwirq(struct fsl_msi *msi,
>>>> struct platform_device *dev,
>>>> static const struct of_device_id fsl_of_msi_ids[];
>>>> static int fsl_of_msi_probe(struct platform_device *dev)
>>>> {
>>>> - const struct of_device_id *match;
>>>> struct fsl_msi *msi;
>>>> struct resource res, msiir;
>>>> int err, i, j, irq_index, count;
>>>> @@ -397,10 +396,7 @@ static int fsl_of_msi_probe(struct platform_device
>>>> *dev)
>>>> u32 offset;
>>>> struct pci_controller *phb;
>>>>
>>>> - match = of_match_device(fsl_of_msi_ids, &dev->dev);
>>>> - if (!match)
>>>> - return -EINVAL;
>>>> - features = match->data;
>>>> + features = of_device_get_match_data(&dev->dev);
>>>
>>> What happens when features is NULL ?
>>
>> I did jump at that one too, but as it turns out, it cannot happen, by
>> construction. All the fsl_of_msi_ids[] entries have a non-NULL .data
>> pointer, and you only enter probe if you match a fsl_of_msi_ids[]
>> entry with the DT.
>>
>> So the current check for a NULL match is not something that can happen
>> short of some other bug somewhere.
>>
>
> Ok.
>
> Then it would be good to have a sentence explaining that in the commit
> message.
Yes I agree. Too many of these cleanup patches assume the reviewer is
intimately familiar with the details of the new API/helper and don't
explain things fully in the change log.
The helper is:
const void *of_device_get_match_data(const struct device *dev)
{
const struct of_device_id *match;
match = of_match_device(dev->driver->of_match_table, dev);
if (!match)
return NULL;
return match->data;
}
So as Marc says, if we're in probe then there must be a match.
IMHO there should be a check for match->data being NULL. Although the
current match table contains a non-NULL data for every element, that
could easily change in future (although this driver will probably never
be updated).
The forward declaration of fsl_of_msi_ids should also be removed, as it
will no longer be necessary.
cheers
