[RFC PATCH 5/6] iommu: Hook up '->unmap_pages' driver callback

[Will Deacon]

Extend iommu_pgsize() to populate an optional 'count' paramater so that
we can direct unmapping operation to the ->unmap_pages callback if it
has been provided by the driver.

Signed-off-by: Will Deacon <will at kernel.org>
---
 drivers/iommu/iommu.c | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index ab689611a03b..fe186691fc21 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2358,7 +2358,7 @@ phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
 
 static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
-			   phys_addr_t paddr, size_t size)
+			   phys_addr_t paddr, size_t size, size_t *count)
 {
 	unsigned int pgsize_idx;
 	unsigned long pgsizes;
@@ -2379,6 +2379,8 @@ static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
 	pgsize_idx = __fls(pgsizes);
 	pgsize = BIT(pgsize_idx);
 
+	if (count)
+		*count = size >> pgsize_idx;
 	return pgsize;
 }
 
@@ -2416,7 +2418,7 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
 
 	while (size) {
-		size_t pgsize = iommu_pgsize(domain, iova, paddr, size);
+		size_t pgsize = iommu_pgsize(domain, iova, paddr, size, NULL);
 
 		pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
 			 iova, &paddr, pgsize);
@@ -2467,6 +2469,19 @@ int iommu_map_atomic(struct iommu_domain *domain, unsigned long iova,
 }
 EXPORT_SYMBOL_GPL(iommu_map_atomic);
 
+static size_t __iommu_unmap_pages(struct iommu_domain *domain,
+				  unsigned long iova, size_t size,
+				  struct iommu_iotlb_gather *iotlb_gather)
+{
+	const struct iommu_ops *ops = domain->ops;
+	size_t pgsize, count;
+
+	pgsize = iommu_pgsize(domain, iova, iova, size, &count);
+	return ops->unmap_pages ?
+	       ops->unmap_pages(domain, iova, pgsize, count, iotlb_gather) :
+	       ops->unmap(domain, iova, pgsize, iotlb_gather);
+}
+
 static size_t __iommu_unmap(struct iommu_domain *domain,
 			    unsigned long iova, size_t size,
 			    struct iommu_iotlb_gather *iotlb_gather)
@@ -2504,10 +2519,9 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 	 * or we hit an area that isn't mapped.
 	 */
 	while (unmapped < size) {
-		size_t pgsize;
-
-		pgsize = iommu_pgsize(domain, iova, iova, size - unmapped);
-		unmapped_page = ops->unmap(domain, iova, pgsize, iotlb_gather);
+		unmapped_page = __iommu_unmap_pages(domain, iova,
+						    size - unmapped,
+						    iotlb_gather);
 		if (!unmapped_page)
 			break;
 
-- 
2.31.0.291.g576ba9dcdaf-goog