diff options
| author | Maarten Lankhorst <maarten.lankhorst@linux.intel.com> | 2023-04-12 12:01:32 +0200 |
|---|---|---|
| committer | Maarten Lankhorst <maarten.lankhorst@linux.intel.com> | 2023-04-12 12:01:32 +0200 |
| commit | 5603effb8295ada8419408d038a34ca89d658229 (patch) | |
| tree | b06d8e309631d507c7b030e943b8479e2d15250b /kernel/trace/ring_buffer.c | |
| parent | b89ce1177d42d5c124e83f3858818cd4e6a2c46f (diff) | |
| parent | 09a9639e56c01c7a00d6c0ca63f4c7c41abe075d (diff) | |
Merge remote-tracking branch 'drm/drm-fixes' into drm-misc-fixes
We were stuck on rc2, should at least attempt to track drm-fixes
slightly.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Diffstat (limited to 'kernel/trace/ring_buffer.c')
| -rw-r--r-- | kernel/trace/ring_buffer.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index af50d931b020..76a2d91eecad 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -354,10 +354,6 @@ static void rb_init_page(struct buffer_data_page *bpage) local_set(&bpage->commit, 0); } -/* - * Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing - * this issue out. - */ static void free_buffer_page(struct buffer_page *bpage) { free_page((unsigned long)bpage->page); @@ -3102,6 +3098,10 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer) if (RB_WARN_ON(cpu_buffer, rb_is_reader_page(cpu_buffer->tail_page))) return; + /* + * No need for a memory barrier here, as the update + * of the tail_page did it for this page. + */ local_set(&cpu_buffer->commit_page->page->commit, rb_page_write(cpu_buffer->commit_page)); rb_inc_page(&cpu_buffer->commit_page); @@ -3111,6 +3111,8 @@ rb_set_commit_to_write(struct ring_buffer_per_cpu *cpu_buffer) while (rb_commit_index(cpu_buffer) != rb_page_write(cpu_buffer->commit_page)) { + /* Make sure the readers see the content of what is committed. */ + smp_wmb(); local_set(&cpu_buffer->commit_page->page->commit, rb_page_write(cpu_buffer->commit_page)); RB_WARN_ON(cpu_buffer, @@ -4688,7 +4690,12 @@ rb_get_reader_page(struct ring_buffer_per_cpu *cpu_buffer) /* * Make sure we see any padding after the write update - * (see rb_reset_tail()) + * (see rb_reset_tail()). + * + * In addition, a writer may be writing on the reader page + * if the page has not been fully filled, so the read barrier + * is also needed to make sure we see the content of what is + * committed by the writer (see rb_set_commit_to_write()). */ smp_rmb(); |