On Fri, Apr 10, 2020 at 7:14 AM Al Viro <viro@xxxxxxxxxxxxxxxxxx> wrote:
>
> On Fri, Apr 10, 2020 at 07:05:22AM +0200, Miklos Szeredi wrote:
> > + /* read after we'd reached the end? */
> > + if (*pos && list_empty(&mnt->mnt_list))
> > + return NULL;
> > +
> > + lock_ns_list(p->ns);
> > + if (!*pos)
> > + mnt = list_first_entry(&p->ns->list, typeof(*mnt), mnt_list);
> > + mnt = mnt_skip_cursors(p->ns, mnt);
> > + unlock_ns_list(p->ns);
> >
> > - p->cached_event = p->ns->event;
> > - p->cached_mount = seq_list_start(&p->ns->list, *pos);
> > - p->cached_index = *pos;
> > - return p->cached_mount;
> > + return mnt;
> > }
>
> Hmm... I wonder if it would be better to do something like
> if (!*pos)
> prev = &p->ns->list.next;
> else
> prev = &p->mnt.mnt_list.next;
> mnt = mnt_skip_cursors(p->ns, prev);
>
> > static void *m_next(struct seq_file *m, void *v, loff_t *pos)
> > {
> > struct proc_mounts *p = m->private;
> > + struct mount *mnt = v;
> > +
> > + lock_ns_list(p->ns);
> > + mnt = mnt_skip_cursors(p->ns, list_next_entry(mnt, mnt_list));
>
> ... and mnt = mnt_skip_cursors(p->ns, &mnt->mnt_list.next);
If you prefer that, yes. Functionally it's equivalent.
Thanks,
Miklos
