On Tue, 2013-03-12 at 11:53 +0100, Jiri Olsa wrote:
> > @@ -316,7 +316,7 @@ void rb_free(struct ring_buffer *rb)
> > struct page *
> > perf_mmap_to_page(struct ring_buffer *rb, unsigned long pgoff)
> > {
> > - if (pgoff > (1UL << page_order(rb)))
> > + if (pgoff > rb->nr_pages)
> > return NULL;
>
> here it's the '>' that masks that there's actually (rb->nr_pages + 1) pages
>
> >
> > return vmalloc_to_page((void *)rb->user_page + pgoff * PAGE_SIZE);
> > @@ -336,7 +336,7 @@ static void rb_free_work(struct work_struct *work)
> > int i, nr;
> >
> > rb = container_of(work, struct ring_buffer, work);
> > - nr = 1 << page_order(rb);
> > + nr = rb->nr_pages;
> >
> > base = rb->user_page;
> > for (i = 0; i < nr + 1; i++)
>
> and here's the user plus one
Right, we could make that either '< nr' and '<= nr' or '<= nr+1' and '<
nr+1'. No real preference either way, but you're right in that being
consistent here makes sense.
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