On Fri, Oct 04, 2024 at 01:45:09PM -0700, Song Liu wrote:
> On Wed, Oct 2, 2024 at 11:09 AM Namhyung Kim <namhyung@xxxxxxxxxx> wrote:
> >
> [...]
> > +
> > +static void *kmem_cache_iter_seq_start(struct seq_file *seq, loff_t *pos)
> > +{
> > + loff_t cnt = 0;
> > + bool found = false;
> > + struct kmem_cache *s;
> > +
> > + mutex_lock(&slab_mutex);
> > +
> > + /*
> > + * Find an entry at the given position in the slab_caches list instead
> > + * of keeping a reference (of the last visited entry, if any) out of
> > + * slab_mutex. It might miss something if one is deleted in the middle
> > + * while it releases the lock. But it should be rare and there's not
> > + * much we can do about it.
> > + */
> > + list_for_each_entry(s, &slab_caches, list) {
> > + if (cnt == *pos) {
> > + /*
> > + * Make sure this entry remains in the list by getting
> > + * a new reference count. Note that boot_cache entries
> > + * have a negative refcount, so don't touch them.
> > + */
> > + if (s->refcount > 0)
> > + s->refcount++;
> > + found = true;
> > + break;
> > + }
> > + cnt++;
> > + }
> > + mutex_unlock(&slab_mutex);
> > +
> > + if (!found)
> > + return NULL;
> > +
> > + ++*pos;
>
> This should be
>
> if (*pos == 0)
> ++*pos;
Oh, I thought there's check for seq->count after the seq->op->show()
for the ->start(). I need to check this logic again, thanks for
pointing this out.
Thanks,
Namhyung
>
> > + return s;
> > +}
> > +
> > +static void kmem_cache_iter_seq_stop(struct seq_file *seq, void *v)
> [...]
