[PATCH v3 1/5] iommu: Implement generic_iommu_put_resv_regions()

[Thierry Reding <thierry.reding@gmail.com>]

From: Thierry Reding <treding@nvidia.com>

Implement a generic function for removing reserved regions. This can be
used by drivers that don't do anything fancy with these regions other
than allocating memory for them.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/iommu/iommu.c | 19 +++++++++++++++++++
 include/linux/iommu.h |  2 ++
 2 files changed, 21 insertions(+)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index fdd40756dbc1..101f2d68eb6e 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2229,6 +2229,25 @@ void iommu_put_resv_regions(struct device *dev, struct list_head *list)
 		ops->put_resv_regions(dev, list);
 }
 
+/**
+ * generic_iommu_put_resv_regions - Reserved region driver helper
+ * @dev: device for which to free reserved regions
+ * @list: reserved region list for device
+ *
+ * IOMMU drivers can use this to implement their .put_resv_regions() callback
+ * for simple reservations. Memory allocated for each reserved region will be
+ * freed. If an IOMMU driver allocates additional resources per region, it is
+ * going to have to implement a custom callback.
+ */
+void generic_iommu_put_resv_regions(struct device *dev, struct list_head *list)
+{
+	struct iommu_resv_region *entry, *next;
+
+	list_for_each_entry_safe(entry, next, list, list)
+		kfree(entry);
+}
+EXPORT_SYMBOL(generic_iommu_put_resv_regions);
+
 struct iommu_resv_region *iommu_alloc_resv_region(phys_addr_t start,
 						  size_t length, int prot,
 						  enum iommu_resv_type type)
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 1b4fbe703950..2e06b31579c2 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -477,6 +477,8 @@ extern void iommu_set_fault_handler(struct iommu_domain *domain,
 
 extern void iommu_get_resv_regions(struct device *dev, struct list_head *list);
 extern void iommu_put_resv_regions(struct device *dev, struct list_head *list);
+extern void generic_iommu_put_resv_regions(struct device *dev,
+					   struct list_head *list);
 extern int iommu_request_dm_for_dev(struct device *dev);
 extern int iommu_request_dma_domain_for_dev(struct device *dev);
 extern void iommu_set_default_passthrough(bool cmd_line);
-- 
2.24.1

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