On Thu, 2014-01-23 at 11:31 -0800, Nicholas A. Bellinger wrote:
> On Thu, 2014-01-23 at 20:12 +0100, Peter Zijlstra wrote:
> > On Thu, Jan 23, 2014 at 10:40:04AM -0800, Nicholas A. Bellinger wrote:
> > > On Wed, 2014-01-22 at 11:53 -0800, Nicholas A. Bellinger wrote:
> > > > Hi Peter,
> > > >
> > > > Does this satisfy your questions..?
> > > >
> > > > Do you have any more concerns about TASK_RUNNING + prepare_to_wait()
> > > > usage in percpu_ida_alloc() that need to be addressed before I can drop
> > > > this series into target-pending/for-next to address the original bug..?
> > > >
> > >
> > > Given the silence,
> >
> > You mean the silence in which I send a 4+ emails earlier today?
> >
> > > I'll assume your OK with the initial TASK_RUNNING +
> > > prepare_to_wait() bit, right..?
> >
> > No, I would prefer not to do that. While it does work its awkward at
> > best.
>
> AFAICT, those changes don't address the original bug that the series was
> trying to address, allowing the percpu_ida_alloc() tag stealing slow
> path to be interrupted by a signal..
>
> Also, keep in mind this change needs to be backported to >= v3.12, which
> is why the percpu_ida changes have been kept to a minimum.
>
<A little too eager to SEND>
So would you prefer the following addition to the original bugfix
instead..?
diff --git a/lib/percpu_ida.c b/lib/percpu_ida.c
index a48ce2e..58b6714 100644
--- a/lib/percpu_ida.c
+++ b/lib/percpu_ida.c
@@ -174,7 +174,8 @@ int percpu_ida_alloc(struct percpu_ida *pool, int state)
*
* global lock held and irqs disabled, don't need percpu lock
*/
- prepare_to_wait(&pool->wait, &wait, state);
+ if (state != TASK_RUNNING)
+ prepare_to_wait(&pool->wait, &wait, state);
if (!tags->nr_free)
alloc_global_tags(pool, tags);
@@ -199,8 +200,9 @@ int percpu_ida_alloc(struct percpu_ida *pool, int state)
local_irq_save(flags);
tags = this_cpu_ptr(pool->tag_cpu);
}
+ if (state != TASK_RUNNING)
+ finish_wait(&pool->wait, &wait);
- finish_wait(&pool->wait, &wait);
return tag;
}
EXPORT_SYMBOL_GPL(percpu_ida_alloc);
--
To unsubscribe from this list: send the line "unsubscribe target-devel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
