* [PATCH] i2c: mux: Use struct_size() in devm_kzalloc()
@ 2019-05-29 16:20 Gustavo A. R. Silva
2019-06-11 7:12 ` Peter Rosin
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-05-29 16:20 UTC (permalink / raw)
To: Peter Rosin, Wolfram Sang; +Cc: linux-i2c, 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[];
};
instance = devm_kzalloc(dev, sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = devm_kzalloc(dev, 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/i2c/i2c-mux.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/i2c/i2c-mux.c b/drivers/i2c/i2c-mux.c
index 603252fa1284..8d5e4c6fdd8e 100644
--- a/drivers/i2c/i2c-mux.c
+++ b/drivers/i2c/i2c-mux.c
@@ -243,8 +243,7 @@ struct i2c_mux_core *i2c_mux_alloc(struct i2c_adapter *parent,
{
struct i2c_mux_core *muxc;
- muxc = devm_kzalloc(dev, sizeof(*muxc)
- + max_adapters * sizeof(muxc->adapter[0])
+ muxc = devm_kzalloc(dev, struct_size(muxc, adapter, max_adapters)
+ sizeof_priv, GFP_KERNEL);
if (!muxc)
return NULL;
--
2.21.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] i2c: mux: Use struct_size() in devm_kzalloc()
2019-05-29 16:20 [PATCH] i2c: mux: Use struct_size() in devm_kzalloc() Gustavo A. R. Silva
@ 2019-06-11 7:12 ` Peter Rosin
0 siblings, 0 replies; 2+ messages in thread
From: Peter Rosin @ 2019-06-11 7:12 UTC (permalink / raw)
To: Gustavo A. R. Silva, Wolfram Sang; +Cc: linux-i2c, linux-kernel
On 2019-05-29 18:20, 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;
> struct boo entry[];
> };
>
> instance = devm_kzalloc(dev, sizeof(struct foo) + count * sizeof(struct boo), GFP_KERNEL);
>
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
>
> instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);
>
> This code was detected with the help of Coccinelle.
Thanks, patch applied to i2c-mux/for-next
Cheers,
Peter
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