[PATCH v11 1/9] iommu: Introduce a callback to struct iommu_resv_region

Shameer Kolothum
2022-04-22T16:29:47Z

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.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
drivers/iommu/iommu.c | 16 +++++++++++-----
include/linux/iommu.h | 2 ++
2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index f2c45b85b9fc..ffcfa684e80c 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2597,16 +2597,22 @@ 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
index 9208eca4b0d1..68bcfb3a06d7 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -134,6 +134,7 @@ 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;
@@ -141,6 +142,7 @@ struct iommu_resv_region {
size_t length;
int prot;
enum iommu_resv_type type;
+ void (*free)(struct device *dev, struct iommu_resv_region *region);
};

/**
--
2.17.1