Re: [PATCH 3/3] nvmem: core: use is_bin_visible for permissions

[Srinivas Kandagatla]

On 24/03/2020 17:46, Greg KH wrote:
> On Tue, Mar 24, 2020 at 05:16:00PM +0000, Srinivas Kandagatla wrote:
> > By using is_bin_visible callback to set permissions will remove a large list
> > of attribute groups. These group permissions can be dynamically derived in
> > the callback.
> >
> > Suggested-by: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> > ---
> >   drivers/nvmem/nvmem-sysfs.c | 74 +++++++++----------------------------
> >   1 file changed, 18 insertions(+), 56 deletions(-)
> >
> > diff --git a/drivers/nvmem/nvmem-sysfs.c b/drivers/nvmem/nvmem-sysfs.c
> > index 8759c4470012..1ff1801048f6 100644
> > --- a/drivers/nvmem/nvmem-sysfs.c
> > +++ b/drivers/nvmem/nvmem-sysfs.c
> > @@ -103,6 +103,17 @@ static ssize_t bin_attr_nvmem_write(struct file *filp, struct kobject *kobj,
> >   
> >   	return count;
> >   }
> > +static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
> > +					 struct bin_attribute *attr, int i)
> > +{
> > +	struct device *dev = container_of(kobj, struct device, kobj);
> > +	struct nvmem_device *nvmem = to_nvmem_device(dev);
> > +
> > +	if (nvmem->root_only)
> > +		return nvmem->read_only ? 0400 : 0600;
> > +
> > +	return nvmem->read_only ? 0444 : 0644;
> > +}
>
> I don't know why this is so hard for me to read, but how about this
> instead:
>
> static umode_t nvmem_bin_attr_is_visible(struct kobject *kobj,
> 					 struct bin_attribute *attr, int i)
> {
> 	struct device *dev = container_of(kobj, struct device, kobj);
> 	struct nvmem_device *nvmem = to_nvmem_device(dev);
> 	umode_t mode = 0400;
>
> 	if (!nvmem->root_only)
> 		mode |= 0044;
>
> 	if (!nvmem->read_only)
> 		mode |= 0200;
>
> 	return mode;
> }
>
> Did I get the logic corect?

That looks perfect and matches what is in upstream!
Thanks for suggesting this cleanup!

I will send v2 with this change!

--srini
> thanks,
>
> greg k-h