On Thu, Sep 03, 2026 at 01:16:01PM -0400, Steven Rostedt wrote:
> On Tue, 1 Sep 2026 16:54:45 +0100
> Vincent Donnefort <[email protected]> wrote:
>
> > -static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer, int
> > idx)
> > +static void *rb_range_buffer(struct ring_buffer_per_cpu *cpu_buffer,
> > unsigned int idx)
> > {
> > struct ring_buffer_cpu_meta *meta;
> > + unsigned int subbuf_size;
> > unsigned long ptr;
> > - int subbuf_size;
> >
> > meta = rb_range_meta(cpu_buffer->buffer, 0, cpu_buffer->cpu);
> > if (!meta)
> > @@ -1777,7 +1776,7 @@ static void *rb_range_buffer(struct
> > ring_buffer_per_cpu *cpu_buffer, int idx)
> >
> > ptr = (unsigned long)rb_subbufs_from_meta(meta);
> >
> > - ptr += subbuf_size * idx;
> > + ptr += (unsigned long)subbuf_size * idx;
>
> Really, it looks like the idx should be typecasted, as it is the number of
> subbuffers. Maybe even pass it in as unsigned long?
__rb_allocate_pages() is passing idx as a number pages, so yeah that'd make
more sense, even though a persistent buffer is capped to a 30-bits nr_pages.
>
> > if (ptr + subbuf_size > cpu_buffer->buffer->range_addr_end)
> > return NULL;
> >
> > @@ -1854,13 +1853,13 @@ static bool rb_meta_init(struct trace_buffer
> > *buffer, int scratch_size)
> > * must be the same.
> > */
> > static bool rb_cpu_meta_valid(struct ring_buffer_cpu_meta *meta, int cpu,
> > - struct trace_buffer *buffer, int nr_pages,
> > + struct trace_buffer *buffer, unsigned long
> > nr_pages,
> > unsigned long *subbuf_mask)
> > {
> > - int subbuf_size = PAGE_SIZE;
> > + unsigned long subbuf_size = PAGE_SIZE;
>
> Why the long? Shouldn't it be unsigned int?
That is to cheat to not have to add a cast in
buffers_end = meta->first_buffer + (subbuf_size * meta->nr_subbufs);
>
> > unsigned long buffers_start;
> > unsigned long buffers_end;
> > - int i;
> > + unsigned long i;
> >
> > if (!subbuf_mask)
> > return false;
> > @@ -2109,8 +2108,8 @@ static void rb_meta_validate_events(struct
> > ring_buffer_per_cpu *cpu_buffer)
> > struct buffer_page *head_page, *orig_head, *orig_reader;
> > struct rb_validation_state state = { 0 };
> > bool skip = false;
> > + unsigned long i;
> > int ret;
> > - int i;
> >
> > if (!meta || !meta->head_buffer)
> > return;
> > @@ -2161,7 +2160,7 @@ static void rb_meta_validate_events(struct
> > ring_buffer_per_cpu *cpu_buffer)
> > rb_validate_buffer(head_page, cpu_buffer, meta, &state, 0,
> > state.ts);
> > }
> > if (i)
> > - pr_info("Ring buffer [%d] rewound %d pages\n", cpu_buffer->cpu,
> > i);
> > + pr_info("Ring buffer [%d] rewound %lu pages\n",
> > cpu_buffer->cpu, i);
> >
> > /* The last rewound page must be skipped. */
> > if (head_page != orig_head)
> > @@ -2245,7 +2244,8 @@ static void rb_meta_validate_events(struct
> > ring_buffer_per_cpu *cpu_buffer)
> > }
> > }
> >
> > -static void rb_range_meta_init(struct trace_buffer *buffer, int nr_pages,
> > int scratch_size)
> > +static void rb_range_meta_init(struct trace_buffer *buffer,
> > + unsigned long nr_pages, int scratch_size)
>
> static void rb_range_meta_init(struct trace_buffer *buffer, unsigned long
> nr_pages,
> int scratch_size)
>
> looks better ;-)
ack
--
Vincent
>
> > {
> > struct ring_buffer_cpu_meta *meta;
> > unsigned long *subbuf_mask;
> > @@ -2345,8 +2345,8 @@ static int rbm_show(struct seq_file *m, void *v)
> > rb_meta_subbuf_idx(meta, (void *)meta->head_buffer));
> > seq_printf(m, "commit_buffer: %d\n",
> > rb_meta_subbuf_idx(meta, (void
> > *)meta->commit_buffer));
> > - seq_printf(m, "subbuf_size: %d\n", meta->subbuf_size);
> > - seq_printf(m, "nr_subbufs: %d\n", meta->nr_subbufs);
> > + seq_printf(m, "subbuf_size: %u\n", meta->subbuf_size);
> > + seq_printf(m, "nr_subbufs: %u\n", meta->nr_subbufs);
> > return 0;
> > }
> >
>
>
> -- Steve
