* [PATCH] IB/cm: Use struct_size() in kmalloc()
@ 2019-01-07 17:26 Gustavo A. R. Silva
2019-01-07 18:48 ` Jason Gunthorpe
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-01-07 17:26 UTC (permalink / raw)
To: Doug Ledford, Jason Gunthorpe
Cc: linux-rdma, 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 = kmalloc(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 = kmalloc(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/infiniband/core/cm.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index edb2cb758be7..af7f74faa448 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -4052,8 +4052,7 @@ static void cm_recv_handler(struct ib_mad_agent *mad_agent,
atomic_long_inc(&port->counter_group[CM_RECV].
counter[attr_id - CM_ATTR_ID_OFFSET]);
- work = kmalloc(sizeof(*work) + sizeof(struct sa_path_rec) * paths,
- GFP_KERNEL);
+ work = kmalloc(struct_size(work, path, paths), GFP_KERNEL);
if (!work) {
ib_free_recv_mad(mad_recv_wc);
return;
--
2.20.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] IB/cm: Use struct_size() in kmalloc()
2019-01-07 17:26 [PATCH] IB/cm: Use struct_size() in kmalloc() Gustavo A. R. Silva
@ 2019-01-07 18:48 ` Jason Gunthorpe
0 siblings, 0 replies; 2+ messages in thread
From: Jason Gunthorpe @ 2019-01-07 18:48 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: Doug Ledford, linux-rdma, linux-kernel
On Mon, Jan 07, 2019 at 11:26:16AM -0600, 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 = kmalloc(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 = kmalloc(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/infiniband/core/cm.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
Applied to for-next thanks
Jason
^ permalink raw reply [flat|nested] 2+ messages in thread
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2019-01-07 17:26 [PATCH] IB/cm: Use struct_size() in kmalloc() Gustavo A. R. Silva
2019-01-07 18:48 ` Jason Gunthorpe
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