i2c: mux: demux-pinctrl: 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>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Peter Rosin <peda@axentia.se>

diff --git a/drivers/i2c/muxes/i2c-demux-pinctrl.c b/drivers/i2c/muxes/i2c-demux-pinctrl.c
index 035032e..012b45e 100644 (file)
--- a/drivers/i2c/muxes/i2c-demux-pinctrl.c
+++ b/drivers/i2c/muxes/i2c-demux-pinctrl.c
@@ -219,8 +219,8 @@ static int i2c_demux_pinctrl_probe(struct platform_device *pdev)
                return -EINVAL;
        }
 
-       priv = devm_kzalloc(&pdev->dev, sizeof(*priv)
-                          + num_chan * sizeof(struct i2c_demux_pinctrl_chan), GFP_KERNEL);
+       priv = devm_kzalloc(&pdev->dev, struct_size(priv, chan, num_chan),
+                           GFP_KERNEL);
 
        props = devm_kcalloc(&pdev->dev, num_chan, sizeof(*props), GFP_KERNEL);