Messages in this thread | | | Date | Fri, 24 Jan 2014 16:14:37 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH-v2 1/3] percpu_ida: Make percpu_ida_alloc + callers accept task state bitmask |
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On Thu, Jan 23, 2014 at 11:38:24AM -0800, Nicholas A. Bellinger wrote: > > 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.
Well, the other option is to revert whatever caused the issue in the first place :-)
I'm not much for making ugly fixes just because its easier to backport.
> <A little too eager to SEND> > > So would you prefer the following addition to the original bugfix > instead..?
I'll make a right old mess out of percpu_ida.c, but yeah.
> 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); > >
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