diff options
Diffstat (limited to 'include/linux/ring_buffer.h')
| -rw-r--r-- | include/linux/ring_buffer.h | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h index e1b7b2173885..f0aa486d131c 100644 --- a/include/linux/ring_buffer.h +++ b/include/linux/ring_buffer.h @@ -68,9 +68,38 @@ ring_buffer_event_time_delta(struct ring_buffer_event *event) return event->time_delta; } +/* + * ring_buffer_event_discard can discard any event in the ring buffer. + * it is up to the caller to protect against a reader from + * consuming it or a writer from wrapping and replacing it. + * + * No external protection is needed if this is called before + * the event is commited. But in that case it would be better to + * use ring_buffer_discard_commit. + * + * Note, if an event that has not been committed is discarded + * with ring_buffer_event_discard, it must still be committed. + */ void ring_buffer_event_discard(struct ring_buffer_event *event); /* + * ring_buffer_discard_commit will remove an event that has not + * ben committed yet. If this is used, then ring_buffer_unlock_commit + * must not be called on the discarded event. This function + * will try to remove the event from the ring buffer completely + * if another event has not been written after it. + * + * Example use: + * + * if (some_condition) + * ring_buffer_discard_commit(buffer, event); + * else + * ring_buffer_unlock_commit(buffer, event); + */ +void ring_buffer_discard_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event); + +/* * size is in bytes for each per CPU buffer. */ struct ring_buffer * |