cpufreq: e_powersaver: Use struct_size() in 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 = kzalloc(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 = kzalloc(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: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/e_powersaver.c b/drivers/cpufreq/e_powersaver.c
index 60bea30..2d3ef20 100644 (file)
--- a/drivers/cpufreq/e_powersaver.c
+++ b/drivers/cpufreq/e_powersaver.c
@@ -323,9 +323,8 @@ static int eps_cpu_init(struct cpufreq_policy *policy)
                states = 2;
 
        /* Allocate private data and frequency table for current cpu */
-       centaur = kzalloc(sizeof(*centaur)
-                   + (states + 1) * sizeof(struct cpufreq_frequency_table),
-                   GFP_KERNEL);
+       centaur = kzalloc(struct_size(centaur, freq_table, states + 1),
+                         GFP_KERNEL);
        if (!centaur)
                return -ENOMEM;
        eps_cpu[0] = centaur;