Commit b27b0017 authored Jun 21, 2019 by Gustavo A. R. Silva Committed by Bartlomiej Zolnierkiewicz Jun 21, 2019

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>

parent acf7287e

drivers/video/fbdev/mmp/hw/mmp_ctrl.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -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;