Re: [PATCH] cpufreq: e_powersaver: Use struct_size() in kzalloc()

Rafael J. Wysocki
2019-01-24T10:34:28Z

On Tuesday, January 8, 2019 6:00:56 AM CET Viresh Kumar wrote:
> On 07-01-19, 11:33, Gustavo A. R. Silva wrote:
> > 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>
> > ---
> > drivers/cpufreq/e_powersaver.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/cpufreq/e_powersaver.c b/drivers/cpufreq/e_powersaver.c
> > index 60bea302abbe..2d3ef208dd70 100644
> > --- 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;
>
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

Patch applied, thanks!