* [PATCH] Input: tca6416-keypad: use struct_size() in kzalloc()
@ 2019-01-08 15:28 Gustavo A. R. Silva
2019-01-12 1:47 ` Dmitry Torokhov
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-08 15:28 UTC (permalink / raw)
To: Dmitry Torokhov; +Cc: linux-input, linux-kernel, Gustavo A. R. Silva
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/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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] Input: tca6416-keypad: use struct_size() in kzalloc()
2019-01-08 15:28 [PATCH] Input: tca6416-keypad: use struct_size() in kzalloc() Gustavo A. R. Silva
@ 2019-01-12 1:47 ` Dmitry Torokhov
0 siblings, 0 replies; 2+ messages in thread
From: Dmitry Torokhov @ 2019-01-12 1:47 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: linux-input, linux-kernel
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 <gustavo@embeddedor.com>
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
^ permalink raw reply [flat|nested] 2+ messages in thread
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