| Message ID | 20190619142655.GA20218@embeddedor (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 3d4149ec87fdab5006cb94f8ebe4720b1ee7e564 |
| Headers | show |
| Series | Input: gpio_keys_polled - use struct_size() in devm_kzalloc() | expand |
On Wed, Jun 19, 2019 at 09:26:55AM -0500, 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 gpio_keys_polled_dev { > ... > struct gpio_keys_button_data data[0]; > }; > > size = sizeof(struct gpio_keys_polled_dev) + count * sizeof(struct gpio_keys_button_data); > instance = devm_kzalloc(dev, size, GFP_KERNEL); > > Instead of leaving these open-coded and prone to type mistakes, we can > now use the new struct_size() helper: > > instance = devm_kzalloc(dev, struct_size(instance, data, count), GFP_KERNEL); > > Notice that, in this case, variable size is not necessary, hence it > is removed. > > 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/gpio_keys_polled.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c > index edc7262103b9..c4087be0c2e0 100644 > --- a/drivers/input/keyboard/gpio_keys_polled.c > +++ b/drivers/input/keyboard/gpio_keys_polled.c > @@ -235,7 +235,6 @@ static int gpio_keys_polled_probe(struct platform_device *pdev) > struct gpio_keys_polled_dev *bdev; > struct input_polled_dev *poll_dev; > struct input_dev *input; > - size_t size; > int error; > int i; > > @@ -250,9 +249,8 @@ static int gpio_keys_polled_probe(struct platform_device *pdev) > return -EINVAL; > } > > - size = sizeof(struct gpio_keys_polled_dev) + > - pdata->nbuttons * sizeof(struct gpio_keys_button_data); > - bdev = devm_kzalloc(dev, size, GFP_KERNEL); > + bdev = devm_kzalloc(dev, struct_size(bdev, data, pdata->nbuttons), > + GFP_KERNEL); > if (!bdev) { > dev_err(dev, "no memory for private data\n"); > return -ENOMEM; > -- > 2.21.0 >
diff --git a/drivers/input/keyboard/gpio_keys_polled.c b/drivers/input/keyboard/gpio_keys_polled.c index edc7262103b9..c4087be0c2e0 100644 --- a/drivers/input/keyboard/gpio_keys_polled.c +++ b/drivers/input/keyboard/gpio_keys_polled.c @@ -235,7 +235,6 @@ static int gpio_keys_polled_probe(struct platform_device *pdev) struct gpio_keys_polled_dev *bdev; struct input_polled_dev *poll_dev; struct input_dev *input; - size_t size; int error; int i; @@ -250,9 +249,8 @@ static int gpio_keys_polled_probe(struct platform_device *pdev) return -EINVAL; } - size = sizeof(struct gpio_keys_polled_dev) + - pdata->nbuttons * sizeof(struct gpio_keys_button_data); - bdev = devm_kzalloc(dev, size, GFP_KERNEL); + bdev = devm_kzalloc(dev, struct_size(bdev, data, pdata->nbuttons), + GFP_KERNEL); if (!bdev) { dev_err(dev, "no memory for private data\n"); return -ENOMEM;
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 gpio_keys_polled_dev { ... struct gpio_keys_button_data data[0]; }; size = sizeof(struct gpio_keys_polled_dev) + count * sizeof(struct gpio_keys_button_data); instance = devm_kzalloc(dev, size, GFP_KERNEL); Instead of leaving these open-coded and prone to type mistakes, we can now use the new struct_size() helper: instance = devm_kzalloc(dev, struct_size(instance, data, count), GFP_KERNEL); Notice that, in this case, variable size is not necessary, hence it is removed. This code was detected with the help of Coccinelle. Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- drivers/input/keyboard/gpio_keys_polled.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)