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;
struct boo entry[];
};
size = sizeof(struct foo) + count * sizeof(struct boo);
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, entry, 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@xxxxxxxxxxxxxx>
---
drivers/video/fbdev/mmp/hw/mmp_ctrl.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/video/fbdev/mmp/hw/mmp_ctrl.c b/drivers/video/fbdev/mmp/hw/mmp_ctrl.c
index 87d943f15a12..17174cd7a5bb 100644
--- a/drivers/video/fbdev/mmp/hw/mmp_ctrl.c
+++ b/drivers/video/fbdev/mmp/hw/mmp_ctrl.c
@@ -433,7 +433,7 @@ static int mmphw_probe(struct platform_device *pdev)
{
struct mmp_mach_plat_info *mi;
struct resource *res;
- int ret, i, size, irq;
+ int ret, i, irq;
struct mmphw_path_plat *path_plat;
struct mmphw_ctrl *ctrl = NULL;
@@ -461,9 +461,9 @@ static int mmphw_probe(struct platform_device *pdev)
}
/* allocate */
- size = sizeof(struct mmphw_ctrl) + sizeof(struct mmphw_path_plat) *
- mi->path_num;
- ctrl = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);
+ ctrl = devm_kzalloc(&pdev->dev,
+ struct_size(ctrl, path_plats, mi->path_num),
+ GFP_KERNEL);
if (!ctrl) {
ret = -ENOMEM;
goto failed;
--
2.21.0
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