i40e: Use struct_size() in kzalloc()

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);
instance = kzalloc(size, 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)

Notice that, in this case, variable size is not necessary, hence it
is removed.

This code was detected with the help of Coccinelle.

Signed-off-by: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

diff --git a/drivers/net/ethernet/intel/i40e/i40e_client.c b/drivers/net/ethernet/intel/i40e/i40e_client.c
index 5f3b8b9..e81530c 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_client.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_client.c
@@ -578,11 +578,9 @@ static int i40e_client_setup_qvlist(struct i40e_info *ldev,
        struct i40e_hw *hw = &pf->hw;
        struct i40e_qv_info *qv_info;
        u32 v_idx, i, reg_idx, reg;
-       u32 size;
 
-       size = sizeof(struct i40e_qvlist_info) +
-              (sizeof(struct i40e_qv_info) * (qvlist_info->num_vectors - 1));
-       ldev->qvlist_info = kzalloc(size, GFP_KERNEL);
+       ldev->qvlist_info = kzalloc(struct_size(ldev->qvlist_info, qv_info,
+                                   qvlist_info->num_vectors - 1), GFP_KERNEL);
        if (!ldev->qvlist_info)
                return -ENOMEM;
        ldev->qvlist_info->num_vectors = qvlist_info->num_vectors;