[PATCH] spi: Use struct_size() helper

From: Gustavo A. R. Silva
Date: Fri Jun 07 2019 - 14:53:07 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 spi_replaced_transfers {
struct spi_transfer inserted_transfers[];

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:

insert * sizeof(struct spi_transfer) + sizeof(struct spi_replaced_transfers)


struct_size(rxfer, inserted_transfers, insert)

This code was detected with the help of Coccinelle.

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

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index e0cd8ccfe92d..69e492ed414a 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2769,8 +2769,7 @@ struct spi_replaced_transfers *spi_replace_transfers(

/* allocate the structure using spi_res */
rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
- insert * sizeof(struct spi_transfer)
- + sizeof(struct spi_replaced_transfers)
+ struct_size(rxfer, inserted_transfers, insert)
+ extradatasize,
if (!rxfer)