From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Gustavo A. R. Silva" Subject: Re: [PATCH] cpufreq: e_powersaver: Use struct_size() in kzalloc() Date: Thu, 24 Jan 2019 11:33:52 -0600 Message-ID: References: <20190107173343.GA4258@embeddedor> <20190108050056.quckhd2d5ah4ywax@vireshk-i7> <1645829.9I2fkU6ktd@aspire.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1645829.9I2fkU6ktd@aspire.rjw.lan> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" , Viresh Kumar Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org On 1/24/19 4:34 AM, Rafael J. Wysocki wrote: > 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 >>> --- >>> 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 > > Patch applied, thanks! > Thank you both, Viresh and Rafael. -- Gustavo