Messages in this thread | | | From | Michael Ellerman <> | Subject | Re: [PATCH] powerpc/sysdev: Use of_device_get_match_data() | Date | Mon, 07 Mar 2022 11:44:55 +1100 |
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Christophe Leroy <christophe.leroy@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.leroy@csgroup.eu> wrote: >>> Le 04/03/2022 à 02:18, cgel.zte@gmail.com a écrit : >>>> From: Minghao Chi (CGEL ZTE) <chi.minghao@zte.com.cn> >>>> >>>> Use of_device_get_match_data() to simplify the code. >>>> >>>> Reported-by: Zeal Robot <zealci@zte.com.cn> >>>> Signed-off-by: Minghao Chi (CGEL ZTE) <chi.minghao@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
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