Subject: [PATCH v2 3/5] iommu/arm-smmu-v3: Make arm_smmu_install_ste_for_dev return void

From: [email-masked] (Will Deacon)
Date: Fri, 10 Mar 2017 20:49:34 +0000

arm_smmu_install_ste_for_dev cannot fail and always returns 0, however
the fact that it returns int means that callers end up implementing
redundant error handling code which complicates STE tracking and is
never executed.

This patch changes the return type of arm_smmu_install_ste_for_dev
to avoid, to make it explicit that it cannot fail.

Signed-off-by: Will Deacon <[email-masked]>
---
 drivers/iommu/arm-smmu-v3.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 3d38e682071a..e18dbcd26f66 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1579,7 +1579,7 @@ static __le64 *arm_smmu_get_step_for_sid(struct arm_smmu_device *smmu, u32 sid)
 	return step;
 }
 
-static int arm_smmu_install_ste_for_dev(struct iommu_fwspec *fwspec)
+static void arm_smmu_install_ste_for_dev(struct iommu_fwspec *fwspec)
 {
 	int i;
 	struct arm_smmu_master_data *master = fwspec->iommu_priv;
@@ -1591,8 +1591,6 @@ static int arm_smmu_install_ste_for_dev(struct iommu_fwspec *fwspec)
 
 		arm_smmu_write_strtab_ent(smmu, sid, step, &master->ste);
 	}
-
-	return 0;
 }
 
 static void arm_smmu_detach_dev(struct device *dev)
@@ -1600,8 +1598,7 @@ static void arm_smmu_detach_dev(struct device *dev)
 	struct arm_smmu_master_data *master = dev->iommu_fwspec->iommu_priv;
 
 	master->ste.bypass = true;
-	if (arm_smmu_install_ste_for_dev(dev->iommu_fwspec) < 0)
-		dev_warn(dev, "failed to install bypass STE\n");
+	arm_smmu_install_ste_for_dev(dev->iommu_fwspec);
 }
 
 static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
@@ -1653,10 +1650,7 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		ste->s2_cfg = &smmu_domain->s2_cfg;
 	}
 
-	ret = arm_smmu_install_ste_for_dev(dev->iommu_fwspec);
-	if (ret < 0)
-		ste->valid = false;
-
+	arm_smmu_install_ste_for_dev(dev->iommu_fwspec);
 out_unlock:
 	mutex_unlock(&smmu_domain->init_mutex);
 	return ret;
-- 
2.1.4