[net-next] xprtrdma: Use struct_size() in kzalloc()
diff mbox series

Message ID 20190131004622.GA30261@embeddedor
State New
Headers show
Series
  • [net-next] xprtrdma: Use struct_size() in kzalloc()
Related show

Commit Message

Gustavo A. R. Silva Jan. 31, 2019, 12:46 a.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 foo {
    int stuff;
    struct boo entry[];
};

instance = kzalloc(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 = 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>
---
 net/sunrpc/xprtrdma/verbs.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

Comments

Chuck Lever Jan. 31, 2019, 2:11 p.m. UTC | #1
> On Jan 30, 2019, at 7:46 PM, 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[];
> };
> 
> instance = kzalloc(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 = 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>

Reviewed-by: Chuck Lever <chuck.lever@oracle.com>


> ---
> net/sunrpc/xprtrdma/verbs.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
> index 4994e75945b8..9e8cf7456840 100644
> --- a/net/sunrpc/xprtrdma/verbs.c
> +++ b/net/sunrpc/xprtrdma/verbs.c
> @@ -811,8 +811,7 @@ static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
> {
> 	struct rpcrdma_sendctx *sc;
> 
> -	sc = kzalloc(sizeof(*sc) +
> -		     ia->ri_max_send_sges * sizeof(struct ib_sge),
> +	sc = kzalloc(struct_size(sc, sc_sges, ia->ri_max_send_sges),
> 		     GFP_KERNEL);
> 	if (!sc)
> 		return NULL;
> -- 
> 2.20.1
> 

--
Chuck Lever
Gustavo A. R. Silva Feb. 8, 2019, 3:49 a.m. UTC | #2
On 1/31/19 8:11 AM, Chuck Lever wrote:
> 
> 
>> On Jan 30, 2019, at 7:46 PM, 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[];
>> };
>>
>> instance = kzalloc(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 = 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>
> 
> Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
> 

Thanks, Chuck.

--
Gustavo
Gustavo A. R. Silva March 28, 2019, 8:41 p.m. UTC | #3
Hi all,

Friendly ping:

Who can take this?

Thanks
--
Gustavo

On 1/31/19 8:11 AM, Chuck Lever wrote:
> 
> 
>> On Jan 30, 2019, at 7:46 PM, 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[];
>> };
>>
>> instance = kzalloc(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 = 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>
> 
> Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
> 
> 
>> ---
>> net/sunrpc/xprtrdma/verbs.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
>> index 4994e75945b8..9e8cf7456840 100644
>> --- a/net/sunrpc/xprtrdma/verbs.c
>> +++ b/net/sunrpc/xprtrdma/verbs.c
>> @@ -811,8 +811,7 @@ static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
>> {
>> 	struct rpcrdma_sendctx *sc;
>>
>> -	sc = kzalloc(sizeof(*sc) +
>> -		     ia->ri_max_send_sges * sizeof(struct ib_sge),
>> +	sc = kzalloc(struct_size(sc, sc_sges, ia->ri_max_send_sges),
>> 		     GFP_KERNEL);
>> 	if (!sc)
>> 		return NULL;
>> -- 
>> 2.20.1
>>
> 
> --
> Chuck Lever
> 
> 
>

Patch
diff mbox series

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 4994e75945b8..9e8cf7456840 100644
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -811,8 +811,7 @@  static struct rpcrdma_sendctx *rpcrdma_sendctx_create(struct rpcrdma_ia *ia)
 {
 	struct rpcrdma_sendctx *sc;
 
-	sc = kzalloc(sizeof(*sc) +
-		     ia->ri_max_send_sges * sizeof(struct ib_sge),
+	sc = kzalloc(struct_size(sc, sc_sges, ia->ri_max_send_sges),
 		     GFP_KERNEL);
 	if (!sc)
 		return NULL;