diff options
| -rw-r--r-- | kernel/trace/ring_buffer.c | 49 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 4 |
2 files changed, 45 insertions, 8 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 683aa57870fe..e40f5c6d7908 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -6003,6 +6003,39 @@ static void rb_clear_buffer_page(struct buffer_page *page) page->read = 0; } +/* + * When the buffer is memory mapped to user space, each sub buffer + * has a unique id that is used by the meta data to tell the user + * where the current reader page is. + * + * For a normal allocated ring buffer, the id is saved in the buffer page + * id field, and updated via this function. + * + * But for a fixed memory mapped buffer, the id is already assigned for + * fixed memory ording in the memory layout and can not be used. Instead + * the index of where the page lies in the memory layout is used. + * + * For the normal pages, set the buffer page id with the passed in @id + * value and return that. + * + * For fixed memory mapped pages, get the page index in the memory layout + * and return that as the id. + */ +static int rb_page_id(struct ring_buffer_per_cpu *cpu_buffer, + struct buffer_page *bpage, int id) +{ + /* + * For boot buffers, the id is the index, + * otherwise, set the buffer page with this id + */ + if (cpu_buffer->ring_meta) + id = rb_meta_subbuf_idx(cpu_buffer->ring_meta, bpage->page); + else + bpage->id = id; + + return id; +} + static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer) { struct trace_buffer_meta *meta = cpu_buffer->meta_page; @@ -6011,7 +6044,9 @@ static void rb_update_meta_page(struct ring_buffer_per_cpu *cpu_buffer) return; meta->reader.read = cpu_buffer->reader_page->read; - meta->reader.id = cpu_buffer->reader_page->id; + meta->reader.id = rb_page_id(cpu_buffer, cpu_buffer->reader_page, + cpu_buffer->reader_page->id); + meta->reader.lost_events = cpu_buffer->lost_events; meta->entries = local_read(&cpu_buffer->entries); @@ -6927,23 +6962,29 @@ static void rb_setup_ids_meta_page(struct ring_buffer_per_cpu *cpu_buffer, struct trace_buffer_meta *meta = cpu_buffer->meta_page; unsigned int nr_subbufs = cpu_buffer->nr_pages + 1; struct buffer_page *first_subbuf, *subbuf; + int cnt = 0; int id = 0; - subbuf_ids[id] = (unsigned long)cpu_buffer->reader_page->page; - cpu_buffer->reader_page->id = id++; + id = rb_page_id(cpu_buffer, cpu_buffer->reader_page, id); + subbuf_ids[id++] = (unsigned long)cpu_buffer->reader_page->page; + cnt++; first_subbuf = subbuf = rb_set_head_page(cpu_buffer); do { + id = rb_page_id(cpu_buffer, subbuf, id); + if (WARN_ON(id >= nr_subbufs)) break; subbuf_ids[id] = (unsigned long)subbuf->page; - subbuf->id = id; rb_inc_page(&subbuf); id++; + cnt++; } while (subbuf != first_subbuf); + WARN_ON(cnt != nr_subbufs); + /* install subbuf ID to kern VA translation */ cpu_buffer->subbuf_ids = subbuf_ids; diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 5b8db27fb6ef..73d75cdb7e5b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -8508,10 +8508,6 @@ static int tracing_buffers_mmap(struct file *filp, struct vm_area_struct *vma) if (iter->tr->flags & TRACE_ARRAY_FL_MEMMAP) return -ENODEV; - /* Currently the boot mapped buffer is not supported for mmap */ - if (iter->tr->flags & TRACE_ARRAY_FL_BOOT) - return -ENODEV; - ret = get_snapshot_map(iter->tr); if (ret) return ret; |