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@xxxxxxxxxxxxxx>
---
drivers/dma/qcom/bam_dma.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/dma/qcom/bam_dma.c b/drivers/dma/qcom/bam_dma.c
index 1617715aa6e0..cb860cb53c27 100644
--- a/drivers/dma/qcom/bam_dma.c
+++ b/drivers/dma/qcom/bam_dma.c
@@ -636,8 +636,8 @@ static struct dma_async_tx_descriptor *bam_prep_slave_sg(struct dma_chan *chan,
num_alloc += DIV_ROUND_UP(sg_dma_len(sg), BAM_FIFO_SIZE);
/* allocate enough room to accomodate the number of entries */
- async_desc = kzalloc(sizeof(*async_desc) +
- (num_alloc * sizeof(struct bam_desc_hw)), GFP_NOWAIT);
+ async_desc = kzalloc(struct_size(async_desc, desc, num_alloc),
+ GFP_NOWAIT);
if (!async_desc)
goto err_out;
--
2.20.1
