Re: [PATCH v3 24/25] iommu/dma: Factor out flush queue init

[Robin Murphy]

On 2021-08-09 20:05, Rajat Jain wrote:
> On Wed, Aug 4, 2021 at 10:16 AM Robin Murphy <robin.murphy@xxxxxxx> wrote:
> > Factor out flush queue setup from the initial domain init so that we
> > can potentially trigger it from sysfs later on in a domain's lifetime.
> >
> > Reviewed-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Reviewed-by: John Garry <john.garry@xxxxxxxxxx>
> > Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
> > ---
> >   drivers/iommu/dma-iommu.c | 30 ++++++++++++++++++++----------
> >   include/linux/dma-iommu.h |  9 ++++++---
> >   2 files changed, 26 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> > index 2e19505dddf9..f51b8dc99ac6 100644
> > --- a/drivers/iommu/dma-iommu.c
> > +++ b/drivers/iommu/dma-iommu.c
> > @@ -310,6 +310,25 @@ static bool dev_is_untrusted(struct device *dev)
> >          return dev_is_pci(dev) && to_pci_dev(dev)->untrusted;
> >   }
> >
> > +int iommu_dma_init_fq(struct iommu_domain *domain)
> > +{
> > +       struct iommu_dma_cookie *cookie = domain->iova_cookie;
> > +
> > +       if (domain->type != IOMMU_DOMAIN_DMA_FQ)
> > +               return -EINVAL;
> > +       if (cookie->fq_domain)
> > +               return 0;
> > +
> > +       if (init_iova_flush_queue(&cookie->iovad, iommu_dma_flush_iotlb_all,
> > +                                 iommu_dma_entry_dtor)) {
> > +               pr_warn("iova flush queue initialization failed\n");
> > +               domain->type = IOMMU_DOMAIN_DMA;
> > +               return -ENODEV;
> > +       }
> > +       cookie->fq_domain = domain;
> > +       return 0;
> > +}
> > +
> >   /**
> >    * iommu_dma_init_domain - Initialise a DMA mapping domain
> >    * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
> > @@ -362,16 +381,7 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
> >          }
> >
> >          init_iova_domain(iovad, 1UL << order, base_pfn);
> > -
> > -       if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain) {
> > -               if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
> > -                                         iommu_dma_entry_dtor)) {
> > -                       pr_warn("iova flush queue initialization failed\n");
> > -                       domain->type = IOMMU_DOMAIN_DMA;
> > -               } else {
> > -                       cookie->fq_domain = domain;
> > -               }
> > -       }
> > +       iommu_dma_init_fq(domain);
> >
> >          return iova_reserve_iommu_regions(dev, domain);
> >   }
> > diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h
> > index 758ca4694257..81ab647f1618 100644
> > --- a/include/linux/dma-iommu.h
> > +++ b/include/linux/dma-iommu.h
> > @@ -20,6 +20,7 @@ void iommu_put_dma_cookie(struct iommu_domain *domain);
> >
> >   /* Setup call for arch DMA mapping code */
> >   void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 dma_limit);
> > +int iommu_dma_init_fq(struct iommu_domain *domain);
> >
> >   /* The DMA API isn't _quite_ the whole story, though... */
> >   /*
> > @@ -37,9 +38,6 @@ void iommu_dma_compose_msi_msg(struct msi_desc *desc,
> >
> >   void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list);
> >
> > -void iommu_dma_free_cpu_cached_iovas(unsigned int cpu,
> > -               struct iommu_domain *domain);
> > -
>
> This looks like an unrelated code cleanup. Should this be a separate patch?

Ha, busted! Much of this was done in the "stream of consciousness" style 
where I made a big sprawling mess then split it up into patches and 
branches afterwards. TBH it was already feeling pretty tenuous having a 
separate patch just to move this one function, and it only gets more so 
with the simplification Will pointed out earlier. I think I'll squash 
iommu_dma_init_fq() into the next patch then do a thorough header sweep, 
since I've now spotted some things in iova.h which could probably go as 
well.

Thanks for the poke!

Robin.

> Thanks,
>
> Rajat
>
>
> >   extern bool iommu_dma_forcedac;
> >
> >   #else /* CONFIG_IOMMU_DMA */
> > @@ -54,6 +52,11 @@ static inline void iommu_setup_dma_ops(struct device *dev, u64 dma_base,
> >   {
> >   }
> >
> > +static inline int iommu_dma_init_fq(struct iommu_domain *domain)
> > +{
> > +       return -EINVAL;
> > +}
> > +
> >   static inline int iommu_get_dma_cookie(struct iommu_domain *domain)
> >   {
> >          return -ENODEV;
> > --
> > 2.25.1