| Message ID | 20190618152325.GA21504@embeddedor (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 002cdb95dc398919bd37d3228c677a22c5ca1498 |
| Headers | show |
| Series | Input: gpio_keys - use struct_size() in devm_kzalloc() | expand |
On Tue, Jun 18, 2019 at 10:23:25AM -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_drvdata { > ... > struct gpio_button_data data[0]; > }; > > > size = sizeof(struct gpio_keys_drvdata) + count * sizeof(struct gpio_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.c | 6 ++---- > 1 file changed, 2 insertions(+), 4 deletions(-) > > diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c > index 6cd199e8a370..c186c2552b04 100644 > --- a/drivers/input/keyboard/gpio_keys.c > +++ b/drivers/input/keyboard/gpio_keys.c > @@ -774,7 +774,6 @@ static int gpio_keys_probe(struct platform_device *pdev) > struct fwnode_handle *child = NULL; > struct gpio_keys_drvdata *ddata; > struct input_dev *input; > - size_t size; > int i, error; > int wakeup = 0; > > @@ -784,9 +783,8 @@ static int gpio_keys_probe(struct platform_device *pdev) > return PTR_ERR(pdata); > } > > - size = sizeof(struct gpio_keys_drvdata) + > - pdata->nbuttons * sizeof(struct gpio_button_data); > - ddata = devm_kzalloc(dev, size, GFP_KERNEL); > + ddata = devm_kzalloc(dev, struct_size(ddata, data, pdata->nbuttons), > + GFP_KERNEL); > if (!ddata) { > dev_err(dev, "failed to allocate state\n"); > return -ENOMEM; > -- > 2.21.0 >
diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c index 6cd199e8a370..c186c2552b04 100644 --- a/drivers/input/keyboard/gpio_keys.c +++ b/drivers/input/keyboard/gpio_keys.c @@ -774,7 +774,6 @@ static int gpio_keys_probe(struct platform_device *pdev) struct fwnode_handle *child = NULL; struct gpio_keys_drvdata *ddata; struct input_dev *input; - size_t size; int i, error; int wakeup = 0; @@ -784,9 +783,8 @@ static int gpio_keys_probe(struct platform_device *pdev) return PTR_ERR(pdata); } - size = sizeof(struct gpio_keys_drvdata) + - pdata->nbuttons * sizeof(struct gpio_button_data); - ddata = devm_kzalloc(dev, size, GFP_KERNEL); + ddata = devm_kzalloc(dev, struct_size(ddata, data, pdata->nbuttons), + GFP_KERNEL); if (!ddata) { dev_err(dev, "failed to allocate state\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_drvdata { ... struct gpio_button_data data[0]; }; size = sizeof(struct gpio_keys_drvdata) + count * sizeof(struct gpio_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.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)