The subbuf_ids field allows to point to a specific page from the ring-buffer based on its ID. As a preparation or the upcoming ring-buffer remote support, point this array to the buffer_page instead of the buffer_data_page.
Reviewed-by: Steven Rostedt (Google) <[email protected]> Signed-off-by: Vincent Donnefort <[email protected]> diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 1187d632dd5d..a5d11487337e 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -554,7 +554,7 @@ struct ring_buffer_per_cpu { unsigned int mapped; unsigned int user_mapped; /* user space mapping */ struct mutex mapping_lock; - unsigned long *subbuf_ids; /* ID to subbuf VA */ + struct buffer_page **subbuf_ids; /* ID to subbuf VA */ struct trace_buffer_meta *meta_page; struct ring_buffer_cpu_meta *ring_meta; @@ -7013,7 +7013,7 @@ static void rb_free_meta_page(struct ring_buffer_per_cpu *cpu_buffer) } static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, - unsigned long *subbuf_ids) + struct buffer_page **subbuf_ids) { struct trace_buffer_meta *meta = cpu_buffer->meta_page; unsigned int nr_subbufs = cpu_buffer->nr_pages + 1; @@ -7022,7 +7022,7 @@ static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, int id = 0; id = rb_page_id(cpu_buffer, cpu_buffer->reader_page, id); - subbuf_ids[id++] = (unsigned long)cpu_buffer->reader_page->page; + subbuf_ids[id++] = cpu_buffer->reader_page; cnt++; first_subbuf = subbuf = rb_set_head_page(cpu_buffer); @@ -7032,7 +7032,7 @@ static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, if (WARN_ON(id >= nr_subbufs)) break; - subbuf_ids[id] = (unsigned long)subbuf->page; + subbuf_ids[id] = subbuf; rb_inc_page(&subbuf); id++; @@ -7041,7 +7041,7 @@ static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, WARN_ON(cnt != nr_subbufs); - /* install subbuf ID to kern VA translation */ + /* install subbuf ID to bpage translation */ cpu_buffer->subbuf_ids = subbuf_ids; meta->meta_struct_len = sizeof(*meta); @@ -7197,13 +7197,15 @@ static int __rb_map_vma(struct ring_buffer_per_cpu *cpu_buffer, } while (p < nr_pages) { + struct buffer_page *subbuf; struct page *page; int off = 0; if (WARN_ON_ONCE(s >= nr_subbufs)) return -EINVAL; - page = virt_to_page((void *)cpu_buffer->subbuf_ids[s]); + subbuf = cpu_buffer->subbuf_ids[s]; + page = virt_to_page((void *)subbuf->page); for (; off < (1 << (subbuf_order)); off++, page++) { if (p >= nr_pages) @@ -7230,7 +7232,8 @@ 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; + struct buffer_page **subbuf_ids; + unsigned long flags; int err; if (!cpumask_test_cpu(cpu, buffer->cpumask)) @@ -7254,7 +7257,7 @@ int ring_buffer_map(struct trace_buffer *buffer, int cpu, if (err) return err; - /* subbuf_ids include the reader while nr_pages does not */ + /* subbuf_ids includes 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); -- 2.53.0.rc1.225.gd81095ad13-goog
