* [PATCH] dmaengine: axi-dmac: Use struct_size() in kzalloc()
@ 2019-01-09 14:44 Gustavo A. R. Silva
2019-01-20 5:22 ` Vinod Koul
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-09 14:44 UTC (permalink / raw)
To: Lars-Peter Clausen, Dan Williams, Vinod Koul
Cc: dmaengine, linux-kernel, Gustavo A. R. Silva
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>
---
drivers/dma/dma-axi-dmac.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/dma/dma-axi-dmac.c b/drivers/dma/dma-axi-dmac.c
index 15b2453d2647..ffc0adc2f6ce 100644
--- 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;
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] dmaengine: axi-dmac: Use struct_size() in kzalloc()
2019-01-09 14:44 [PATCH] dmaengine: axi-dmac: Use struct_size() in kzalloc() Gustavo A. R. Silva
@ 2019-01-20 5:22 ` Vinod Koul
0 siblings, 0 replies; 2+ messages in thread
From: Vinod Koul @ 2019-01-20 5:22 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Lars-Peter Clausen, Dan Williams, dmaengine, linux-kernel
On 09-01-19, 08:44, Gustavo A. R. Silva wrote:
> 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.
Applied, thanks
--
~Vinod
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