[PATCH] regulator: da9063: Use struct_size() in devm_kzalloc()

[Gustavo A. R. Silva]

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;
    struct boo entry[];
};

size = sizeof(struct foo) + count * sizeof(struct boo);
instance = alloc(size, GFP_KERNEL)

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

instance = alloc(struct_size(instance, entry, count), GFP_KERNEL)

Notice that, in this case, variable size is not necessary, hence it is
removed.

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gust...@embeddedor.com>
---
 drivers/regulator/da9063-regulator.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/regulator/da9063-regulator.c 
b/drivers/regulator/da9063-regulator.c
index a83bbd3dbc37..2b0c7a85306a 100644
--- a/drivers/regulator/da9063-regulator.c
+++ b/drivers/regulator/da9063-regulator.c
@@ -739,7 +739,6 @@ static int da9063_regulator_probe(struct platform_device 
*pdev)
        struct regulator_config config;
        bool bcores_merged, bmem_bio_merged;
        int id, irq, n, n_regulators, ret, val;
-       size_t size;
 
        regl_pdata = da9063_pdata ? da9063_pdata->regulators_pdata : NULL;
 
@@ -784,9 +783,8 @@ static int da9063_regulator_probe(struct platform_device 
*pdev)
                n_regulators--;    /* remove BMEM_BIO_MERGED */
 
        /* Allocate memory required by usable regulators */
-       size = sizeof(struct da9063_regulators) +
-               n_regulators * sizeof(struct da9063_regulator);
-       regulators = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+       regulators = devm_kzalloc(&pdev->dev, struct_size(regulators,
+                                 regulator, n_regulators), GFP_KERNEL);
        if (!regulators)
                return -ENOMEM;
 
-- 
2.20.1