spi: Use struct_size() helper

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)

with:

struct_size(rxfer, inserted_transfers, insert)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 232ed4b..bced687 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2750,8 +2750,7 @@ 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,
                              gfp);
        if (!rxfer)