[PATCH] dmaengine: dma-jz4780: Use struct_size() in devm_kzalloc()

From: Gustavo A. R. Silva
Date: Mon Dec 24 2018 - 01:54:00 EST

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;
void *entry[];

instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, 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);

This issue was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
drivers/dma/dma-jz4780.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/dma-jz4780.c b/drivers/dma/dma-jz4780.c
index a8b6225faa12..9ce0a386225b 100644
--- a/drivers/dma/dma-jz4780.c
+++ b/drivers/dma/dma-jz4780.c
@@ -838,9 +838,8 @@ static int jz4780_dma_probe(struct platform_device *pdev)
if (!soc_data)
return -EINVAL;

- jzdma = devm_kzalloc(dev, sizeof(*jzdma)
- + sizeof(*jzdma->chan) * soc_data->nb_channels,
+ jzdma = devm_kzalloc(dev, struct_size(jzdma, chan,
+ soc_data->nb_channels), GFP_KERNEL);
if (!jzdma)
return -ENOMEM;