On 05/21/2015 06:42 PM, Jiri Denemark wrote:
> Our usage of pthread conditions does not allow a single thread to wait
> for several events from different sources. This is because the condition
> is bound to the source of the event. We can invert the usage by giving
> each thread its own condition and providing APIs for registering this
> thread condition with several sources. Each of the sources can then
> signal the thread condition.
>
> Thread queues also support several threads to be registered with a
> single event source, which can either wakeup all waiting threads or just
> the first one.
>
> Signed-off-by: Jiri Denemark <jdenemar@xxxxxxxxxx>
> ---
> po/POTFILES.in | 1 +
> src/Makefile.am | 2 +
> src/libvirt_private.syms | 15 ++
> src/util/virthreadqueue.c | 343 ++++++++++++++++++++++++++++++++++++++++++++++
> src/util/virthreadqueue.h | 54 ++++++++
> 5 files changed, 415 insertions(+)
> create mode 100644 src/util/virthreadqueue.c
> create mode 100644 src/util/virthreadqueue.h
>
Ran the series through Coverity and came back with this gem
> +
> +void
> +virThreadQueueFree(virThreadQueuePtr queue)
> +{
> + if (!queue)
> + return;
> +
> + while (queue->head)
> + virThreadQueueRemove(queue, queue->head);
(3) Event cond_true: Condition "queue->head", taking true branch
(6) Event loop_begin: Jumped back to beginning of loop
(7) Event cond_true: Condition "queue->head", taking true branch
283 while (queue->head)
(4) Event freed_arg: "virThreadQueueRemove" frees "queue->head". [details]
(5) Event loop: Jumping back to the beginning of the loop
(8) Event deref_arg: Calling "virThreadQueueRemove" dereferences freed pointer "queue->head". [details]
284 virThreadQueueRemove(queue, queue->head);
> + VIR_FREE(queue);
> +}
> +
> +
Where the link to [details] has:
230 static void
231 virThreadQueueRemove(virThreadQueuePtr queue,
232 virThreadQueueItemPtr item)
233 {
(1) Event cond_true: Condition "item->prev", taking true branch
(1) Event deref_parm: Directly dereferencing parameter "item".
Also see events: [freed_arg]
234 if (item->prev)
(2) Event if_fallthrough: Falling through to end of if statement
235 item->prev->next = item->next;
236 else
(3) Event if_end: End of if statement
237 queue->head = item->next;
238
(4) Event cond_true: Condition "item->next", taking true branch
239 if (item->next)
(5) Event if_fallthrough: Falling through to end of if statement
240 item->next->prev = item->prev;
241 else
(6) Event if_end: End of if statement
242 queue->tail = item->prev;
243
244 virObjectUnref(item->cond);
(7) Event freed_arg: "virFree" frees parameter "item". [details]
245 VIR_FREE(item);
246 }
247
John
--
libvir-list mailing list
libvir-list@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/libvir-list