From: Gustavo A. R. Silva Date: Fri, 30 Aug 2019 04:03:27 +0000 (-0500) Subject: iommu/qcom: Use struct_size() helper X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=8758553791dfb31ec2640f6b69df748720c0b1a4;p=openwrt%2Fstaging%2Fblogic.git iommu/qcom: Use struct_size() helper One of the more common cases of allocation size calculations is finding the size of a structure that has a zero-sized array at the end, along with memory for some number of elements for that array. For example: struct qcom_iommu_dev { ... struct qcom_iommu_ctx *ctxs[0]; /* indexed by asid-1 */ }; Make use of the struct_size() helper instead of an open-coded version in order to avoid any potential type mistakes. So, replace the following form: sizeof(*qcom_iommu) + (max_asid * sizeof(qcom_iommu->ctxs[0])) with: struct_size(qcom_iommu, ctxs, max_asid) Also, notice that, in this case, variable sz is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva Signed-off-by: Joerg Roedel --- diff --git a/drivers/iommu/qcom_iommu.c b/drivers/iommu/qcom_iommu.c index 34d0b9783b3e..41cf9bd5a600 100644 --- a/drivers/iommu/qcom_iommu.c +++ b/drivers/iommu/qcom_iommu.c @@ -775,7 +775,7 @@ static int qcom_iommu_device_probe(struct platform_device *pdev) struct qcom_iommu_dev *qcom_iommu; struct device *dev = &pdev->dev; struct resource *res; - int ret, sz, max_asid = 0; + int ret, max_asid = 0; /* find the max asid (which is 1:1 to ctx bank idx), so we know how * many child ctx devices we have: @@ -783,9 +783,8 @@ static int qcom_iommu_device_probe(struct platform_device *pdev) for_each_child_of_node(dev->of_node, child) max_asid = max(max_asid, get_asid(child)); - sz = sizeof(*qcom_iommu) + (max_asid * sizeof(qcom_iommu->ctxs[0])); - - qcom_iommu = devm_kzalloc(dev, sz, GFP_KERNEL); + qcom_iommu = devm_kzalloc(dev, struct_size(qcom_iommu, ctxs, max_asid), + GFP_KERNEL); if (!qcom_iommu) return -ENOMEM; qcom_iommu->num_ctxs = max_asid;