Re: [PATCH 1/5] driver core: make struct class.dev_uevent() take a const *

[Bart Van Assche]

On 11/27/22 05:45, Greg Kroah-Hartman wrote:
> On Fri, Nov 25, 2022 at 03:51:11PM -0800, Bart Van Assche wrote:
> > On 11/23/22 04:25, Greg Kroah-Hartman wrote:
> > > diff --git a/include/linux/mISDNif.h b/include/linux/mISDNif.h
> > > index 7dd1f01ec4f9..7aab4a769736 100644
> > > --- a/include/linux/mISDNif.h
> > > +++ b/include/linux/mISDNif.h
> > > @@ -586,7 +586,7 @@ extern struct mISDNclock *mISDN_register_clock(char *, int, clockctl_func_t *,
> > >    						void *);
> > >    extern void	mISDN_unregister_clock(struct mISDNclock *);
> > > -static inline struct mISDNdevice *dev_to_mISDN(struct device *dev)
> > > +static inline struct mISDNdevice *dev_to_mISDN(const struct device *dev)
> > >    {
> > >    	if (dev)
> > >    		return dev_get_drvdata(dev);
> >
> > Why does the dev_to_mISDN() function drop constness? I haven't found an
> > explanation for this in the cover letter.
>
> I agree, this is going to be fixed up, see the thread starting here:
> 	https://lore.kernel.org/r/Y34+V2bCDdqujBDk@xxxxxxxxx
>
> I'll work on making a const / non const version for these so that we
> don't loose the marking.
>
> Oh wait, no, this function is fine, it's not modifying the device
> structure at all, and only returning the pointer in the private data
> stored in the device.  There is no loss of const-ness here.

Hi Greg,

This is what I found in include/linux/mISDNif.h:

struct mISDNdevice {
	struct mISDNchannel	D;
	u_int			id;
	u_int			Dprotocols;
	u_int			Bprotocols;
	u_int			nrbchan;
	u_char			channelmap[MISDN_CHMAP_SIZE];
	struct list_head	bchannels;
	struct mISDNchannel	*teimgr;
	struct device		dev;
};

As one can see 'dev' is a member of struct mISDNdevice. I still think 
that dev_to_mISDN() drops constness. Did I perhaps overlook something?

Bart.