[PATCH v12 08/17] iommu: Make free of iommu_domain_ops optional

[Lu Baolu <baolu.lu@linux.intel.com>]

So that the drivers are able to implement static singleton instance for
some special domains. The blocking domain is an example. The driver has
no need to allocate different memory for each blocking domain allocation
request. Hence, no need for a free callback.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Tested-by: Zhangfei Gao <zhangfei.gao@linaro.org>
Tested-by: Tony Zhu <tony.zhu@intel.com>
---
 drivers/iommu/iommu.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index e985f4d5895f..630e1b64ed89 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1972,7 +1972,8 @@ void iommu_domain_free(struct iommu_domain *domain)
 	if (domain->type == IOMMU_DOMAIN_SVA)
 		mmdrop(domain->mm);
 	iommu_put_dma_cookie(domain);
-	domain->ops->free(domain);
+	if (domain->ops->free)
+		domain->ops->free(domain);
 }
 EXPORT_SYMBOL_GPL(iommu_domain_free);
 
-- 
2.25.1