[PATCH] ioat/dca: Use struct_size() helper

From: Gustavo A. R. Silva
Date: Wed Aug 28 2019 - 14:41:22 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 ioat_dca_priv {
struct ioat_dca_slot req_slots[0];

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*ioatdca) + (sizeof(struct ioat_dca_slot) * slots)


struct_size(ioatdca, req_slots, slots)

This code was detected with the help of Coccinelle.

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

diff --git a/drivers/dma/ioat/dca.c b/drivers/dma/ioat/dca.c
index 70fd8454d002..be61c32a876f 100644
--- a/drivers/dma/ioat/dca.c
+++ b/drivers/dma/ioat/dca.c
@@ -286,8 +286,7 @@ struct dca_provider *ioat_dca_init(struct pci_dev *pdev, void __iomem *iobase)
return NULL;

dca = alloc_dca_provider(&ioat_dca_ops,
- sizeof(*ioatdca)
- + (sizeof(struct ioat_dca_slot) * slots));
+ struct_size(ioatdca, req_slots, slots));
if (!dca)
return NULL;