Re: [PATCH 2/9] proc: add a read_iter method to proc proc_ops

[Christoph Hellwig]

On Fri, Jun 26, 2020 at 12:06:24PM +0000, Luis Chamberlain wrote:
> On Fri, Jun 26, 2020 at 09:58:29AM +0200, Christoph Hellwig wrote:
> > diff --git a/fs/proc/inode.c b/fs/proc/inode.c
> > index 28d6105e908e4c..fa86619cebc2be 100644
> > --- a/fs/proc/inode.c
> > +++ b/fs/proc/inode.c
> > @@ -297,6 +297,29 @@ static loff_t proc_reg_llseek(struct file *file, 
> > loff_t offset, int whence)
> >     return rv;
> >  }
> >  
> > +static ssize_t pde_read_iter(struct proc_dir_entry *pde, struct kiocb 
> > *iocb,
> > +           struct iov_iter *iter)
> > +{
> > +   if (!pde->proc_ops->proc_read_iter)
> > +           return -EINVAL;
> 
> When is this true?

Whenever a user sets up the method..