iommu/arm-smmu: Use new devm_krealloc()

The implementation-specific subclassing of struct arm_smmu_device really
wanted an appropriate version of realloc(). Now that one exists, take
full advantage of it to clarify what's actually being done here.

Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/355e8d70c7f47d462d85b386aa09f2b5c655f023.1603713428.git.robin.murphy@arm.com
Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/arm/arm-smmu/arm-smmu-impl.c

@@ -91,15 +91,12 @@ static struct arm_smmu_device *cavium_smmu_impl_init(struct arm_smmu_device *smm
 {
 	struct cavium_smmu *cs;
 
-	cs = devm_kzalloc(smmu->dev, sizeof(*cs), GFP_KERNEL);
+	cs = devm_krealloc(smmu->dev, smmu, sizeof(*cs), GFP_KERNEL);
 	if (!cs)
 		return ERR_PTR(-ENOMEM);
 
-	cs->smmu = *smmu;
 	cs->smmu.impl = &cavium_impl;
 
-	devm_kfree(smmu->dev, smmu);
-
 	return &cs->smmu;
 }
 

drivers/iommu/arm/arm-smmu/arm-smmu-nvidia.c

@@ -242,18 +242,10 @@ struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
 	struct nvidia_smmu *nvidia_smmu;
 	struct platform_device *pdev = to_platform_device(dev);
 
-	nvidia_smmu = devm_kzalloc(dev, sizeof(*nvidia_smmu), GFP_KERNEL);
+	nvidia_smmu = devm_krealloc(dev, smmu, sizeof(*nvidia_smmu), GFP_KERNEL);
 	if (!nvidia_smmu)
 		return ERR_PTR(-ENOMEM);
 
-	/*
-	 * Copy the data from struct arm_smmu_device *smmu allocated in
-	 * arm-smmu.c. The smmu from struct nvidia_smmu replaces the smmu
-	 * pointer used in arm-smmu.c once this function returns.
-	 * This is necessary to derive nvidia_smmu from smmu pointer passed
-	 * through arm_smmu_impl function calls subsequently.
-	 */
-	nvidia_smmu->smmu = *smmu;
 	/* Instance 0 is ioremapped by arm-smmu.c. */
 	nvidia_smmu->bases[0] = smmu->base;
 
@@ -267,12 +259,5 @@ struct arm_smmu_device *nvidia_smmu_impl_init(struct arm_smmu_device *smmu)
 
 	nvidia_smmu->smmu.impl = &nvidia_smmu_impl;
 
-	/*
-	 * Free the struct arm_smmu_device *smmu allocated in arm-smmu.c.
-	 * Once this function returns, arm-smmu.c would use arm_smmu_device
-	 * allocated as part of struct nvidia_smmu.
-	 */
-	devm_kfree(dev, smmu);
-
 	return &nvidia_smmu->smmu;
 }

drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c

@@ -159,14 +159,11 @@ struct arm_smmu_device *qcom_smmu_impl_init(struct arm_smmu_device *smmu)
 {
 	struct qcom_smmu *qsmmu;
 
-	qsmmu = devm_kzalloc(smmu->dev, sizeof(*qsmmu), GFP_KERNEL);
+	qsmmu = devm_krealloc(smmu->dev, smmu, sizeof(*qsmmu), GFP_KERNEL);
 	if (!qsmmu)
 		return ERR_PTR(-ENOMEM);
 
-	qsmmu->smmu = *smmu;
-
 	qsmmu->smmu.impl = &qcom_smmu_impl;
-	devm_kfree(smmu->dev, smmu);
 
 	return &qsmmu->smmu;
 }