rpmsg: glink: Use struct_size() helper
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Message ID 20190829181721.GA22554@embeddedor
State New
Headers show
Series
  • rpmsg: glink: Use struct_size() helper
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Commit Message

Gustavo A. R. Silva Aug. 29, 2019, 6:17 p.m. UTC
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 {
	...
	struct intent_pair intents[];
} __packed * msg;

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

So, replace the following form:

sizeof(*msg) + sizeof(struct intent_pair) * count

with:

struct_size(msg, intents, count)

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/rpmsg/qcom_glink_native.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Bjorn Andersson Aug. 29, 2019, 7:09 p.m. UTC | #1
On Thu 29 Aug 11:17 PDT 2019, 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 {
> 	...
> 	struct intent_pair intents[];
> } __packed * msg;
> 
> Make use of the struct_size() helper instead of an open-coded version
> in order to avoid any potential type mistakes.
> 
> So, replace the following form:
> 
> sizeof(*msg) + sizeof(struct intent_pair) * count
> 
> with:
> 
> struct_size(msg, intents, count)
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>

Applied, thanks!

> ---
>  drivers/rpmsg/qcom_glink_native.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index f46c787733e8..621f1afd4d6b 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -892,7 +892,7 @@ static void qcom_glink_handle_intent(struct qcom_glink *glink,
>  		struct intent_pair intents[];
>  	} __packed * msg;
>  
> -	const size_t msglen = sizeof(*msg) + sizeof(struct intent_pair) * count;
> +	const size_t msglen = struct_size(msg, intents, count);
>  	int ret;
>  	int i;
>  	unsigned long flags;
> -- 
> 2.23.0
>
Gustavo A. R. Silva Aug. 29, 2019, 7:15 p.m. UTC | #2
On 8/29/19 2:09 PM, Bjorn Andersson wrote:
> On Thu 29 Aug 11:17 PDT 2019, 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 {
>> 	...
>> 	struct intent_pair intents[];
>> } __packed * msg;
>>
>> Make use of the struct_size() helper instead of an open-coded version
>> in order to avoid any potential type mistakes.
>>
>> So, replace the following form:
>>
>> sizeof(*msg) + sizeof(struct intent_pair) * count
>>
>> with:
>>
>> struct_size(msg, intents, count)
>>
>> This code was detected with the help of Coccinelle.
>>
>> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> 
> Applied, thanks!
> 

Awesome. :)

Thanks!
--
Gustavo

Patch
diff mbox series

diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
index f46c787733e8..621f1afd4d6b 100644
--- a/drivers/rpmsg/qcom_glink_native.c
+++ b/drivers/rpmsg/qcom_glink_native.c
@@ -892,7 +892,7 @@  static void qcom_glink_handle_intent(struct qcom_glink *glink,
 		struct intent_pair intents[];
 	} __packed * msg;
 
-	const size_t msglen = sizeof(*msg) + sizeof(struct intent_pair) * count;
+	const size_t msglen = struct_size(msg, intents, count);
 	int ret;
 	int i;
 	unsigned long flags;