* Steven Rostedt <rostedt@xxxxxxxxxxx> [240410 13:41]:
> On Sat, 6 Apr 2024 18:36:46 +0100
> Vincent Donnefort <vdonnefort@xxxxxxxxxx> wrote:
>
> > +int ring_buffer_map(struct trace_buffer *buffer, int cpu,
> > + struct vm_area_struct *vma)
> > +{
> > + struct ring_buffer_per_cpu *cpu_buffer;
> > + unsigned long flags, *subbuf_ids;
> > + int err = 0;
> > +
> > + if (!cpumask_test_cpu(cpu, buffer->cpumask))
> > + return -EINVAL;
> > +
> > + cpu_buffer = buffer->buffers[cpu];
> > +
> > + mutex_lock(&cpu_buffer->mapping_lock);
> > +
> > + if (cpu_buffer->mapped) {
> > + err = __rb_map_vma(cpu_buffer, vma);
> > + if (!err)
> > + err = __rb_inc_dec_mapped(cpu_buffer, true);
> > + mutex_unlock(&cpu_buffer->mapping_lock);
> > + return err;
> > + }
> > +
> > + /* prevent another thread from changing buffer/sub-buffer sizes */
> > + mutex_lock(&buffer->mutex);
> > +
> > + err = rb_alloc_meta_page(cpu_buffer);
> > + if (err)
> > + goto unlock;
> > +
> > + /* subbuf_ids include the reader while nr_pages does not */
> > + subbuf_ids = kcalloc(cpu_buffer->nr_pages + 1, sizeof(*subbuf_ids), GFP_KERNEL);
> > + if (!subbuf_ids) {
> > + rb_free_meta_page(cpu_buffer);
> > + err = -ENOMEM;
> > + goto unlock;
> > + }
> > +
> > + atomic_inc(&cpu_buffer->resize_disabled);
> > +
> > + /*
> > + * Lock all readers to block any subbuf swap until the subbuf IDs are
> > + * assigned.
> > + */
> > + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
> > + rb_setup_ids_meta_page(cpu_buffer, subbuf_ids);
> > + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
> > +
> > + err = __rb_map_vma(cpu_buffer, vma);
> > + if (!err) {
> > + raw_spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
> > + cpu_buffer->mapped = 1;
> > + raw_spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
> > + } else {
> > + kfree(cpu_buffer->subbuf_ids);
> > + cpu_buffer->subbuf_ids = NULL;
> > + rb_free_meta_page(cpu_buffer);
> > + }
> > +unlock:
>
> Nit: For all labels, please add a space before them. Otherwise, diffs will
> show "unlock" as the function and not "ring_buffer_map", making it harder
> to find where the change is.
>
Isn't the inclusion of a space before labels outdate since 'git diff'
superseds 'diff' and fixed this issue?
Thanks,
Liam
