dmaengine: axi-dmac: Use struct_size() in 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;
    void *entry[];
};

instance = kzalloc(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 = kzalloc(struct_size(instance, entry, count), GFP_KERNEL);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 15b2453d2647fa49e790b6f063785a7d64d19497..ffc0adc2f6ce44625fb0962ae5e688ea66edbdb0 100644 (file)
--- a/drivers/dma/dma-axi-dmac.c
+++ b/drivers/dma/dma-axi-dmac.c
@@ -367,8 +367,7 @@ static struct axi_dmac_desc *axi_dmac_alloc_desc(unsigned int num_sgs)
        struct axi_dmac_desc *desc;
        unsigned int i;
 
-       desc = kzalloc(sizeof(struct axi_dmac_desc) +
-               sizeof(struct axi_dmac_sg) * num_sgs, GFP_NOWAIT);
+       desc = kzalloc(struct_size(desc, sg, num_sgs), GFP_NOWAIT);
        if (!desc)
                return NULL;