dmaengine: tegra-apb: Use struct_size() in devm_kzalloc()

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 foo {
    int stuff;
    void *entry[];
};

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 659b49bf6fdb..cf462b1abc0b 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -1329,8 +1329,9 @@ static int tegra_dma_probe(struct platform_device *pdev)
                 return -ENODEV;
         }
 
-        tdma = devm_kzalloc(&pdev->dev, sizeof(*tdma) + cdata->nr_channels *
-                        sizeof(struct tegra_dma_channel), GFP_KERNEL);
+        tdma = devm_kzalloc(&pdev->dev,
+                            struct_size(tdma, channels, cdata->nr_channels),
+                            GFP_KERNEL);
         if (!tdma)
                 return -ENOMEM;