Re: [PATCH 2/2] virtio-rng: fix stuck in catting hwrng attributes

[Amos Kong <akong@redhat.com>]

On Thu, Sep 11, 2014 at 11:38:38AM +0530, Amit Shah wrote:
> On (Wed) 10 Sep 2014 [17:07:07], Amos Kong wrote:
> > When I check hwrng attributes in sysfs, cat process always gets
> > stuck if guest has only 1 vcpu and uses a slow rng backend.
> > 
> > Currently we check if there is any tasks waiting to be run on
> > current cpu in rng_dev_read() by need_resched(). But need_resched()
> > doesn't work because rng_dev_read() is executing in user context.
> > 
> > This patch removed need_resched() and increase delay to 10 jiffies,
> > then other tasks can have chance to execute protected code.
> > Delaying 1 jiffy also works, but 10 jiffies is safer.

Hi Amit,
 
> I'd prefer two patches for this one: one to remove the need_resched()
> check, and the other to increase the timeout.

If Rusty agrees with this fix, I will respin to update the commitlog
with clear description and split the patches to 3.

Thanks for the review.
 
> Anyway,
> 
> Reviewed-by: Amit Shah <amit.shah@redhat.com>

--
                Amos.