Re: [PATCH] sysfs: add BIN_ATTR_WO() macro

[Nayna]

On 10/01/2019 02:16 PM, Greg Kroah-Hartman wrote:
> On Tue, Oct 01, 2019 at 02:08:53PM -0400, Nayna wrote:
> > Hi Greg,
> >
> >
> > On 08/26/2019 11:01 AM, Greg Kroah-Hartman wrote:
> > > This variant was missing from sysfs.h, I guess no one noticed it before.
> > >
> > > Turns out the powerpc secure variable code can use it, so add it to the
> > > tree for it, and potentially others to take advantage of, instead of
> > > open-coding it.
> > >
> > > Reported-by: Nayna Jain <nayna@xxxxxxxxxxxxx>
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > > ---
> > >
> > > I'll queue this up to my tree for 5.4-rc1, but if you want to take this
> > > in your tree earlier, feel free to do so.
> > >
> > >    include/linux/sysfs.h | 9 +++++++++
> > >    1 file changed, 9 insertions(+)
> > >
> > > diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> > > index 965236795750..5420817ed317 100644
> > > --- a/include/linux/sysfs.h
> > > +++ b/include/linux/sysfs.h
> > > @@ -196,6 +196,12 @@ struct bin_attribute {
> > >    	.size	= _size,						\
> > >    }
> > > +#define __BIN_ATTR_WO(_name) {						\
> > > +	.attr	= { .name = __stringify(_name), .mode = 0200 },		\
> > > +	.store	= _name##_store,					\
> > > +	.size	= _size,						\
> > > +}
> > > +
> > >    #define __BIN_ATTR_RW(_name, _size)					\
> > >    	__BIN_ATTR(_name, 0644, _name##_read, _name##_write, _size)
> > > @@ -208,6 +214,9 @@ struct bin_attribute bin_attr_##_name = __BIN_ATTR(_name, _mode, _read,	\
> > >    #define BIN_ATTR_RO(_name, _size)					\
> > >    struct bin_attribute bin_attr_##_name = __BIN_ATTR_RO(_name, _size)
> > > +#define BIN_ATTR_WO(_name, _size)					\
> > > +struct bin_attribute bin_attr_##_name = __BIN_ATTR_WO(_name, _size)
> > > +
> > >    #define BIN_ATTR_RW(_name, _size)					\
> > >    struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)
> > I am sorry. I didn't notice it via inspection but there is a bug in this
> > macro. When I actually try using it, compilation fails. Here's a likely
> > patch:
> >
> > diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
> > index 5420817ed317..fa7ee503fb76 100644
> > --- a/include/linux/sysfs.h
> > +++ b/include/linux/sysfs.h
> > @@ -196,9 +196,9 @@ struct bin_attribute {
> >          .size   = _size,                                                \
> >   }
> > -#define __BIN_ATTR_WO(_name) {                                         \
> > +#define __BIN_ATTR_WO(_name, _size) {                                  \
> >          .attr   = { .name = __stringify(_name), .mode = 0200 },         \
> > -       .store  = _name##_store,                                        \
> > +       .write  = _name##_write,                                        \
> >          .size   = _size,                                                \
> >   }
> Heh, good catch.  Can you send a real patch for this that I can apply to
> give you the proper credit for finding and fixing this?

Sure.. Thanks Greg !!

Thanks & Regards,
ÂÂÂÂÂ - Nayna