From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bjorn Andersson Subject: Re: [PATCH] drivers: qcom: rpmh: use struct_size() in kzalloc() Date: Mon, 3 Sep 2018 12:07:05 -0700 Message-ID: <20180903190705.GA3456@tuxbook-pro> References: <20180824011753.GA25826@embeddedor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20180824011753.GA25826@embeddedor.com> Sender: linux-kernel-owner@vger.kernel.org To: "Gustavo A. R. Silva" Cc: Andy Gross , David Brown , linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Kees Cook List-Id: linux-arm-msm@vger.kernel.org On Thu 23 Aug 18:17 PDT 2018, 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_ATOMIC); > > 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_ATOMIC); > > This issue was detected with the help of Coccinelle. > > Signed-off-by: Gustavo A. R. Silva Reviewed-by: Bjorn Andersson Regards, Bjorn > --- > drivers/soc/qcom/rpmh.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/soc/qcom/rpmh.c b/drivers/soc/qcom/rpmh.c > index c7beb68..12c057a 100644 > --- a/drivers/soc/qcom/rpmh.c > +++ b/drivers/soc/qcom/rpmh.c > @@ -362,8 +362,7 @@ int rpmh_write_batch(const struct device *dev, enum rpmh_state state, > if (!count) > return -EINVAL; > > - req = kzalloc(sizeof(*req) + count * sizeof(req->rpm_msgs[0]), > - GFP_ATOMIC); > + req = kzalloc(struct_size(req, rpm_msgs, count), GFP_ATOMIC); > if (!req) > return -ENOMEM; > req->count = count; > -- > 2.7.4 >