Re: [PATCH 2/2] chardev: showing minor range for chardev in the output of /proc/devices

[cgxu519]

On 2/12/19 5:02 PM, Greg KH wrote:
> On Tue, Feb 12, 2019 at 04:47:39PM +0800, Chengguang Xu wrote:
> > Currently chardev allows to share major, showing
> > major with minor range for chardev will be more
> > helpful.
> >
> > Signed-off-by: Chengguang Xu <cgxu519@xxxxxxx>
> > ---
> >   fs/char_dev.c | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/char_dev.c b/fs/char_dev.c
> > index b25b1da097d5..6f00acdeb308 100644
> > --- a/fs/char_dev.c
> > +++ b/fs/char_dev.c
> > @@ -55,7 +55,9 @@ void chrdev_show(struct seq_file *f, off_t offset)
> >   	mutex_lock(&chrdevs_lock);
> >   	for (cd = chrdevs[major_to_index(offset)]; cd; cd = cd->next) {
> >   		if (cd->major == offset)
> > -			seq_printf(f, "%3d %s\n", cd->major, cd->name);
> > +			seq_printf(f, "%3d %s (%u-%u)\n", cd->major, cd->name,
> > +				   cd->baseminor,
> > +				   cd->baseminor + cd->minorct - 1);
> You are changing the format of a userspace file, what tools are going to
> break when you do this?

I'll remove this part in V2. Do you have any idea how to get the minor
range info for particular major? Or adding a similar file to somewhere
under /sys is acceptable?

Thanks