iommu: Introduce a callback to struct iommu_resv_region

A callback is introduced to struct iommu_resv_region to free memory allocations associated with the reserved region. This will be useful when we introduce support for IORT RMR based reserved regions. Reviewed-by: Christoph Hellwig <hch@lst.de> Tested-by: Steven Price <steven.price@arm.com> Tested-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> Tested-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> Acked-by: Robin Murphy <robin.murphy@arm.com> Link: https://lore.kernel.org/r/20220615101044.1972-2-shameerali.kolothum.thodi@huawei.com Signed-off-by: Joerg Roedel <jroedel@suse.de>
mariux64 · Jul 6, 2022 · 3b7e248 · 3b7e248
1 parent ac9a5d5
commit 3b7e248
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Showing 2 changed files with 13 additions and 5 deletions.
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
@@ -2590,16 +2590,22 @@ void iommu_put_resv_regions(struct device *dev, struct list_head *list)
  * @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.
+ * for simple reservations. If a per region callback is provided that will be
+ * used to free all memory allocations associated with the reserved region or
+ * else just free up the memory for the regions. 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);
+	list_for_each_entry_safe(entry, next, list, list) {
+		if (entry->free)
+			entry->free(dev, entry);
+		else
+			kfree(entry);
+	}
 }
 EXPORT_SYMBOL(generic_iommu_put_resv_regions);
 

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
@@ -135,13 +135,15 @@ enum iommu_resv_type {
  * @length: Length of the region in bytes
  * @prot: IOMMU Protection flags (READ/WRITE/...)
  * @type: Type of the reserved region
+ * @free: Callback to free associated memory allocations
  */
 struct iommu_resv_region {
 	struct list_head	list;
 	phys_addr_t		start;
 	size_t			length;
 	int			prot;
 	enum iommu_resv_type	type;
+	void (*free)(struct device *dev, struct iommu_resv_region *region);
 };
 
 /**