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

On 2021-08-09 20:05, Rajat Jain wrote:

On Wed, Aug 4, 2021 at 10:16 AM Robin Murphy [off-list ref] wrote:

quoted

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@linux.intel.com>
Reviewed-by: John Garry <redacted>
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
---
  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

quoted

  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

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