Messages in this thread | | | Date | Wed, 1 Apr 2009 22:48:14 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 3/4] ring-buffer: add ring_buffer_discard_commit |
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On Thu, 02 Apr 2009 01:27:24 -0400 Steven Rostedt <rostedt@goodmis.org> wrote:
> From: Steven Rostedt <srostedt@redhat.com> > > The ring_buffer_discard_commit is similar to ring_buffer_event_discard > but it can only be done on an event that has yet to be commited. > Unpredictable results can happen otherwise. > > The main difference between ring_buffer_discard_commit and > ring_buffer_event_discard is that ring_buffer_discard_commit will try > to free the data in the ring buffer if nothing has addded data > after the reserved event. If something did, then it acts almost the > same as ring_buffer_event_discard followed by a > ring_buffer_unlock_commit. > > Note, either ring_buffer_commit_discard and ring_buffer_unlock_commit > can be called on an event, not both. > > This commit also exports both discard functions to be usable by > GPL modules. > > ... > > +/* > + * 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_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) > +{ > + event->type = RINGBUF_TYPE_PADDING; > + /* time delta must be non zero */ > + if (!event->time_delta) > + event->time_delta = 1; > +} > +EXPORT_SYMBOL_GPL(ring_buffer_event_discard);
Seems a bit cumbersome to document the interface partly in the .h file and partly in the .c file?
Doing all of it in the .c file would be typical.
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