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authorSteven Rostedt <srostedt@redhat.com>2009-09-03 15:33:41 -0400
committerSteven Rostedt <rostedt@goodmis.org>2009-09-04 11:36:19 -0400
commitdc892f7339af2d125478b800edb9081d6149665b (patch)
tree3377439556b600c7bd3d53cbc0a893dd75bed634 /kernel
parent7e9391cfedce34eb9786bfa69d7d545dc93ef930 (diff)
downloadop-kernel-dev-dc892f7339af2d125478b800edb9081d6149665b.zip
op-kernel-dev-dc892f7339af2d125478b800edb9081d6149665b.tar.gz
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ring_buffer.c27
1 files changed, 6 insertions, 21 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 9d939e7..092fe0c 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -2328,31 +2328,16 @@ static inline void rb_event_discard(struct ring_buffer_event *event)
}
/**
- * ring_buffer_event_discard - discard any event in the ring buffer
- * @event: the event to discard
- *
- * Sometimes a event that is in the ring buffer needs to be ignored.
- * This function lets the user discard an event in the ring buffer
- * and then that event will not be read later.
- *
- * Note, it is up to the user to be careful with this, and protect
- * against races. If the user discards an event that has been consumed
- * it is possible that it could corrupt the ring buffer.
- */
-void ring_buffer_event_discard(struct ring_buffer_event *event)
-{
- rb_event_discard(event);
-}
-EXPORT_SYMBOL_GPL(ring_buffer_event_discard);
-
-/**
* ring_buffer_commit_discard - discard an event that has not been committed
* @buffer: the ring buffer
* @event: non committed event to discard
*
- * This is similar to ring_buffer_event_discard but must only be
- * performed on an event that has not been committed yet. The difference
- * is that this will also try to free the event from the ring buffer
+ * Sometimes an event that is in the ring buffer needs to be ignored.
+ * This function lets the user discard an event in the ring buffer
+ * and then that event will not be read later.
+ *
+ * This function only works if it is called before the the item has been
+ * committed. It will try to free the event from the ring buffer
* if another event has not been added behind it.
*
* If another event has been added behind it, it will set the event
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