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SubjectRe: [PATCH net-next] svcrdma: Use struct_size() in kmalloc()
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On 1/15/19 3:49 PM, Chuck Lever wrote:
>
>
> On Jan 15, 2019, at 4:11 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 = kmalloc(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 = 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>
>
> Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
>

Thank you, Chuck.
--
Gustavo

>
>> ---
>> net/sunrpc/xprtrdma/svc_rdma_rw.c | 3 +--
>> 1 file changed, 1 insertion(+), 2 deletions(-)
>>
>> diff --git a/net/sunrpc/xprtrdma/svc_rdma_rw.c b/net/sunrpc/xprtrdma/svc_rdma_rw.c
>> index dc1951759a8e..cad37c2122ab 100644
>> --- a/net/sunrpc/xprtrdma/svc_rdma_rw.c
>> +++ b/net/sunrpc/xprtrdma/svc_rdma_rw.c
>> @@ -64,8 +64,7 @@ svc_rdma_get_rw_ctxt(struct svcxprt_rdma *rdma, unsigned int sges)
>> spin_unlock(&rdma->sc_rw_ctxt_lock);
>> } else {
>> spin_unlock(&rdma->sc_rw_ctxt_lock);
>> - ctxt = kmalloc(sizeof(*ctxt) +
>> - SG_CHUNK_SIZE * sizeof(struct scatterlist),
>> + ctxt = kmalloc(struct_size(ctxt, rw_first_sgl, SG_CHUNK_SIZE),
>> GFP_KERNEL);
>> if (!ctxt)
>> goto out;
>> --
>> 2.20.1
>
> --
> Chuck Lever
>
>
>

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