[PATCH][next] iavf: iavf_client: use struct_size() helper

[PATCH][next] iavf: iavf_client: use struct_size() helper

[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);

Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:

size = struct_size(instance, entry, count);

This code was detected with the help of Coccinelle.

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
---
 drivers/net/ethernet/intel/iavf/iavf_client.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/intel/iavf/iavf_client.c b/drivers/net/ethernet/intel/iavf/iavf_client.c
index aea45364fd1c..ab9db7e9f09d 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_client.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_client.c
@@ -451,7 +451,7 @@ static int iavf_client_setup_qvlist(struct i40e_info *ldev,
 	struct i40e_qv_info *qv_info;
 	iavf_status err;
 	u32 v_idx, i;
-	u32 msg_size;
+	size_t msg_size;
 
 	if (adapter->aq_required)
 		return -EAGAIN;
@@ -469,9 +469,8 @@ static int iavf_client_setup_qvlist(struct i40e_info *ldev,
 	}
 
 	v_qvlist_info = (struct virtchnl_iwarp_qvlist_info *)qvlist_info;
-	msg_size = sizeof(struct virtchnl_iwarp_qvlist_info) +
-			(sizeof(struct virtchnl_iwarp_qv_info) *
-			(v_qvlist_info->num_vectors - 1));
+	msg_size = struct_size(v_qvlist_info, qv_info,
+			       v_qvlist_info->num_vectors - 1);
 
 	adapter->client_pending |= BIT(VIRTCHNL_OP_CONFIG_IWARP_IRQ_MAP);
 	err = iavf_aq_send_msg_to_pf(&adapter->hw,
-- 
2.21.0

Re: [PATCH][next] iavf: iavf_client: use struct_size() helper

[Jeff Kirsher]

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On Thu, 2019-03-28 at 15:36 -0500, 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[];
> };
> 
> size = sizeof(struct foo) + count * sizeof(struct boo);
> 
> Instead of leaving these open-coded and prone to type mistakes, we can
> now use the new struct_size() helper:
> 
> size = struct_size(instance, entry, count);
> 
> This code was detected with the help of Coccinelle.
> 
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
>  drivers/net/ethernet/intel/iavf/iavf_client.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)

Thanks Gustavo, I will queue this up.

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