video: fbdev-MMP: Use struct_size() in devm_kzalloc()

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@embeddedor.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>

diff --git a/drivers/video/fbdev/mmp/hw/mmp_ctrl.c b/drivers/video/fbdev/mmp/hw/mmp_ctrl.c
index 87d943f15a12b0f68890a2e62dfb344f5eac8145..17174cd7a5bba5e2046198e29feec88b7133ba8c 100644 (file)
--- 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;