Re: [PATCH v4 4/8] s390/airq: use DMA memory for adapter interrupts

Cornelia Huck
2019-06-12T13:47:09Z

On Wed, 12 Jun 2019 15:33:24 +0200
Halil Pasic <pasic@linux.ibm.com> wrote:

> On Wed, 12 Jun 2019 08:21:27 +0200
> Cornelia Huck <cohuck@redhat.com> wrote:
>
> > On Wed, 12 Jun 2019 02:32:31 +0200
> > Halil Pasic <pasic@linux.ibm.com> wrote:
> >
> > > On Tue, 11 Jun 2019 18:19:44 +0200
> > > Cornelia Huck <cohuck@redhat.com> wrote:
> > >
> > > > On Tue, 11 Jun 2019 16:27:21 +0200
> > > > Halil Pasic <pasic@linux.ibm.com> wrote:
> >
> > > > > IMHO the cleanest thing to do at this stage is to check if the
> > > > > airq_iv_cache is NULL and fail the allocation if it is (to preserve
> > > > > previous behavior).
> > > >
> > > > That's probably the least invasive fix for now. Did you check whether
> > > > any of the other dma pools this series introduces have a similar
> > > > problem due to init not failing?
> > > >
> > >
> > > Good question!
> > >
> > > I did a quick check. virtio_ccw_init() should be OK, because we don't
> > > register the driver if allocation fails, so the thing is going to end
> > > up dysfunctional as expected.
> > >
> > > If however cio_dma_pool_init() fails, then we end up with the same
> > > problem with airqs, just on the !AIRQ_IV_CACHELINE code path. It can be
> > > fixed analogously: make cio_dma_zalloc() fail all allocation if
> > > cio_dma_pool_init() failed before.
> >
> > Ok, makes sense.
>
> v5 is out with the fixes. I have no ack/r-b from you for patch 4. Would
> you like to give some, or should I proceed without?

Please give this some more time, I will look at this later.