Re: [RFC PATCH v6 1/5] iommu: add an exported function to get minimum page size for a domain

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On 13/06/2019 11:20, Yoshihiro Shimoda wrote:
This patch adds an exported function to get minimum page size for
a domain. This patch also modifies similar codes on the iommu.c.

Heh, seeing this gave me a genuine déjà vu moment...

...but it turns out I actually *have* reviewed this patch before :)

https://lore.kernel.org/lkml/05eca601-0264-8141-ceeb-7ef7ad5d5650@xxxxxxx/

Robin.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
  drivers/iommu/iommu.c | 18 +++++++++++++++---
  include/linux/iommu.h |  1 +
  2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 2a90638..7ed16af 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -280,6 +280,18 @@ iommu_insert_device_resv_regions(struct list_head *dev_resv_regions,
  	return ret;
  }
+/**
+ * iommu_get_minimum_page_size - get minimum page size for a domain
+ * @domain: the domain
+ *
+ * Allow iommu driver to get a minimum page size for a domain.
+ */
+unsigned long iommu_get_minimum_page_size(struct iommu_domain *domain)
+{
+	return 1UL << __ffs(domain->pgsize_bitmap);
+}
+EXPORT_SYMBOL_GPL(iommu_get_minimum_page_size);
+
  int iommu_get_group_resv_regions(struct iommu_group *group,
  				 struct list_head *head)
  {
@@ -558,7 +570,7 @@ static int iommu_group_create_direct_mappings(struct iommu_group *group,
BUG_ON(!domain->pgsize_bitmap); - pg_size = 1UL << __ffs(domain->pgsize_bitmap);
+	pg_size = iommu_get_minimum_page_size(domain);
  	INIT_LIST_HEAD(&mappings);
iommu_get_resv_regions(dev, &mappings);
@@ -1595,7 +1607,7 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova,
  		return -EINVAL;
/* find out the minimum page size supported */
-	min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
+	min_pagesz = iommu_get_minimum_page_size(domain);
/*
  	 * both the virtual address and the physical one, as well as
@@ -1655,7 +1667,7 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
  		return 0;
/* find out the minimum page size supported */
-	min_pagesz = 1 << __ffs(domain->pgsize_bitmap);
+	min_pagesz = iommu_get_minimum_page_size(domain);
/*
  	 * The virtual address, as well as the size of the mapping, must be
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 91af22a..7e53b43 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -366,6 +366,7 @@ extern int iommu_request_dma_domain_for_dev(struct device *dev);
  extern struct iommu_resv_region *
  iommu_alloc_resv_region(phys_addr_t start, size_t length, int prot,
  			enum iommu_resv_type type);
+extern unsigned long iommu_get_minimum_page_size(struct iommu_domain *domain);
  extern int iommu_get_group_resv_regions(struct iommu_group *group,
  					struct list_head *head);



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