From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH] Input: tca6416-keypad: use struct_size() in kzalloc() Date: Fri, 11 Jan 2019 17:47:26 -0800 Message-ID: <20190112014726.GB122403@dtor-ws> References: <20190108152816.GA7486@embeddedor> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190108152816.GA7486@embeddedor> Sender: linux-kernel-owner@vger.kernel.org To: "Gustavo A. R. Silva" Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-input@vger.kernel.org On Tue, Jan 08, 2019 at 09:28:16AM -0600, 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 Applied, thank you. > --- > drivers/input/keyboard/tca6416-keypad.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/drivers/input/keyboard/tca6416-keypad.c b/drivers/input/keyboard/tca6416-keypad.c > index dc983ab6c0ad..cdeef180aead 100644 > --- a/drivers/input/keyboard/tca6416-keypad.c > +++ b/drivers/input/keyboard/tca6416-keypad.c > @@ -219,9 +219,7 @@ static int tca6416_keypad_probe(struct i2c_client *client, > return -EINVAL; > } > > - chip = kzalloc(sizeof(struct tca6416_keypad_chip) + > - pdata->nbuttons * sizeof(struct tca6416_button), > - GFP_KERNEL); > + chip = kzalloc(struct_size(chip, buttons, pdata->nbuttons), GFP_KERNEL); > input = input_allocate_device(); > if (!chip || !input) { > error = -ENOMEM; > -- > 2.20.1 > -- Dmitry