Re: [PATCH 07/18] cdev: alias: add support for partition links

[Marco Felsch <m.felsch@pengutronix.de>]

On 25-04-14, Ahmad Fatoum wrote:
> Hello Marco,
> 
> On 4/14/25 12:17, Marco Felsch wrote:
> > On 25-04-14, Ahmad Fatoum wrote:
> >> We currently support bootsource.2, but not bootsource.root-A.
> >> Fix this and while at it, factor out the logic for general reuse.
> >>
> >> Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
> >> ---
> 
> [snip]
> 
> >> -static struct cdev *resolve_partition(struct cdev *cdev,
> >> -				      const char *partname)
> >> -{
> >> -	struct cdev *partcdev;
> >> -
> >> -	if (!partname)
> >> -		return cdev;
> >> -
> >> -	for_each_cdev_partition(partcdev, cdev) {
> >> -		if (streq_ptr(partcdev->partname, partname))
> >> -			return partcdev;
> >> -	}
> >> -
> >> -	return ERR_PTR(-ENODEV);
> >> -}
> >> -
> 
> [snip]
> 
> >> +/**
> >> + * cdev_find_partition - find a partition belonging to a physical device
> >> + *
> >> + * @cdev: the cdev which should be searched for partitions
> >> + * @name: the partition name
> >> + */
> >> +struct cdev *cdev_find_partition(struct cdev *cdevm, const char *name)
> >> +{
> >> +	struct cdev *partcdev;
> >> +
> >> +	if (!name)
> >> +		return cdevm;
> 
> No, I want a NULL name to expand to the parent device. This makes is a
> drop-in replacement for resolve_partition() removed in this same patch.

I have seen that :-) but in the end it was a local function so changes
shouldn't be hard to adapt.

With making the function public avaiable I don't see why
cdev_find_partition() should return the parent device if NULL is
provided. IMHO this is wrong input from the user. What use-case do you
see with returning the parent device?

Regards,
  Marco


> Thanks,
> Ahmad
> 
> > 
> > 		return ERR_PTR(-EINVAL) ?
> > 
> > Regards,
> >   Marco
> > 
> >> +
> >> +	for_each_cdev_partition(partcdev, cdevm) {
> >> +		struct cdev *cdevl;
> >> +
> >> +		if (streq_ptr(partcdev->partname, name))
> >> +			return partcdev;
> >> +
> >> +		list_for_each_entry(cdevl, &partcdev->links, link_entry) {
> >> +			if (streq_ptr(cdevl->partname, name))
> >> +				return cdevl;
> >> +		}
> >> +	}
> >> +
> >> +	return NULL;
> >> +}
> >> +
> >>  /**
> >>   * device_find_partition - find a partition belonging to a physical device
> >>   *
> >> diff --git a/include/driver.h b/include/driver.h
> >> index 3f2c681c0e80..ca002c5164c2 100644
> >> --- a/include/driver.h
> >> +++ b/include/driver.h
> >> @@ -503,6 +503,7 @@ int devfs_create(struct cdev *);
> >>  int devfs_create_link(struct cdev *, const char *name);
> >>  int devfs_remove(struct cdev *);
> >>  int cdev_find_free_index(const char *);
> >> +struct cdev *cdev_find_partition(struct cdev *cdevm, const char *name);
> >>  struct cdev *device_find_partition(struct device *dev, const char *name);
> >>  struct cdev *lcdev_by_name(const char *filename);
> >>  struct cdev *cdev_readlink(struct cdev *cdev);
> >> -- 
> >> 2.39.5
> >>
> >>
> >>
> > 
> 
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