* [PATCH net-next] net: dsa: use struct_size() in devm_kzalloc()
@ 2019-02-08 1:16 Gustavo A. R. Silva
2019-02-08 15:32 ` Vivien Didelot
2019-02-09 6:58 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Gustavo A. R. Silva @ 2019-02-08 1:16 UTC (permalink / raw)
To: Andrew Lunn, Vivien Didelot, Florian Fainelli, David S. Miller
Cc: netdev, 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;
struct boo entry[];
};
size = sizeof(struct foo) + count * sizeof(struct boo);
instance = alloc(size, GFP_KERNEL)
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = alloc(struct_size(instance, entry, count), GFP_KERNEL)
Notice that, in this case, variable size is not necessary, hence it is
removed.
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
net/dsa/dsa2.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index a1917025e155..8c431e0f3627 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -767,11 +767,10 @@ static int dsa_switch_probe(struct dsa_switch *ds)
struct dsa_switch *dsa_switch_alloc(struct device *dev, size_t n)
{
- size_t size = sizeof(struct dsa_switch) + n * sizeof(struct dsa_port);
struct dsa_switch *ds;
int i;
- ds = devm_kzalloc(dev, size, GFP_KERNEL);
+ ds = devm_kzalloc(dev, struct_size(ds, ports, n), GFP_KERNEL);
if (!ds)
return NULL;
--
2.20.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] net: dsa: use struct_size() in devm_kzalloc()
2019-02-08 1:16 [PATCH net-next] net: dsa: use struct_size() in devm_kzalloc() Gustavo A. R. Silva
@ 2019-02-08 15:32 ` Vivien Didelot
2019-02-09 6:58 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Vivien Didelot @ 2019-02-08 15:32 UTC (permalink / raw)
To: Gustavo A. R. Silva
Cc: Andrew Lunn, Florian Fainelli, David S. Miller, netdev,
linux-kernel, Gustavo A. R. Silva
On Thu, 7 Feb 2019 19:16:03 -0600, "Gustavo A. R. Silva" <gustavo@embeddedor.com> 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;
> struct boo entry[];
> };
>
> size = sizeof(struct foo) + count * sizeof(struct boo);
> instance = alloc(size, GFP_KERNEL)
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = alloc(struct_size(instance, entry, count), GFP_KERNEL)
>
> Notice that, in this case, variable size is not necessary, hence it is
> removed.
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH net-next] net: dsa: use struct_size() in devm_kzalloc()
2019-02-08 1:16 [PATCH net-next] net: dsa: use struct_size() in devm_kzalloc() Gustavo A. R. Silva
2019-02-08 15:32 ` Vivien Didelot
@ 2019-02-09 6:58 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2019-02-09 6:58 UTC (permalink / raw)
To: gustavo; +Cc: andrew, vivien.didelot, f.fainelli, netdev, linux-kernel
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Thu, 7 Feb 2019 19:16:03 -0600
> 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;
> struct boo entry[];
> };
>
> size = sizeof(struct foo) + count * sizeof(struct boo);
> instance = alloc(size, GFP_KERNEL)
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = alloc(struct_size(instance, entry, count), GFP_KERNEL)
>
> Notice that, in this case, variable size is not necessary, hence it is
> removed.
>
> This code was detected with the help of Coccinelle.
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Applied.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-02-08 1:16 [PATCH net-next] net: dsa: use struct_size() in devm_kzalloc() Gustavo A. R. Silva
2019-02-08 15:32 ` Vivien Didelot
2019-02-09 6:58 ` David Miller
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