ring-buffer: remove ring_buffer_event_discard

The function ring_buffer_event_discard can be used on any item in the
ring buffer, even after the item was committed. This function provides
no safety nets and is very race prone.

An item may be safely removed from the ring buffer before it is committed
with the ring_buffer_discard_commit.

Since there are currently no users of this function, and because this
function is racey and error prone, this patch removes it altogether.

Note, removing this function also allows the counters to ignore
all discarded events (patches will follow).

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 0 insertions, 14 deletions

diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 7fca71693ae..e061b4ecdc3 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -75,20 +75,6 @@ ring_buffer_event_time_delta(struct ring_buffer_event *event)
 }
 
 /*
- * 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