[RFC PATCH 2/6] iommu: Add an unmap_pages() op for IOMMU drivers

[Will Deacon]

From: "Isaac J. Manjarres" <isaacm at codeaurora.org>

Add a callback for IOMMU drivers to provide a path for the
IOMMU framework to call into an IOMMU driver, which can call
into the io-pgtable code, to unmap a virtually contiguous
range of pages of the same size.

For IOMMU drivers that do not specify an unmap_pages() callback,
the existing logic of unmapping memory one page block at a time
will be used.

Signed-off-by: Isaac J. Manjarres <isaacm at codeaurora.org>
Suggested-by: Will Deacon <will at kernel.org>
Signed-off-by: Will Deacon <will at kernel.org>
---
 include/linux/iommu.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 5e7fe519430a..9cf81242581a 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -193,6 +193,7 @@ struct iommu_iotlb_gather {
  * @detach_dev: detach device from an iommu domain
  * @map: map a physically contiguous memory region to an iommu domain
  * @unmap: unmap a physically contiguous memory region from an iommu domain
+ * @unmap_pages: unmap a number of pages of the same size from an iommu domain
  * @flush_iotlb_all: Synchronously flush all hardware TLBs for this domain
  * @iotlb_sync_map: Sync mappings created recently using @map to the hardware
  * @iotlb_sync: Flush all queued ranges from the hardware TLBs and empty flush
@@ -245,6 +246,9 @@ struct iommu_ops {
 		   phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
 	size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
 		     size_t size, struct iommu_iotlb_gather *iotlb_gather);
+	size_t (*unmap_pages)(struct iommu_domain *domain, unsigned long iova,
+			      size_t pgsize, size_t pgcount,
+			      struct iommu_iotlb_gather *iotlb_gather);
 	void (*flush_iotlb_all)(struct iommu_domain *domain);
 	void (*iotlb_sync_map)(struct iommu_domain *domain, unsigned long iova,
 			       size_t size);
-- 
2.31.0.291.g576ba9dcdaf-goog