i40e/i40e_virtchnl_pf: 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 virtchnl_iwarp_qvlist_info {
	...
        struct virtchnl_iwarp_qv_info qv_info[1];
};

size = sizeof(struct virtchnl_iwarp_qvlist_info) + (sizeof(struct virtchnl_iwarp_qv_info) * count;
instance = kzalloc(size, GFP_KERNEL);

and

struct virtchnl_vf_resource {
	...
        struct virtchnl_vsi_resource vsi_res[1];
};

size = sizeof(struct virtchnl_vf_resource) + sizeof(struct virtchnl_vsi_resource) * count;
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, qv_info, count), GFP_KERNEL);

and

instance = kzalloc(struct_size(instance, vsi_res, count), GFP_KERNEL);

Notice that, in the first case above, 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_virtchnl_pf.c b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
index ac3a130..02b09a8 100644 (file)
--- a/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_virtchnl_pf.c
@@ -440,7 +440,7 @@ static int i40e_config_iwarp_qvlist(struct i40e_vf *vf,
        struct virtchnl_iwarp_qv_info *qv_info;
        u32 v_idx, i, reg_idx, reg;
        u32 next_q_idx, next_q_type;
-       u32 msix_vf, size;
+       u32 msix_vf;
        int ret = 0;
 
        msix_vf = pf->hw.func_caps.num_msix_vectors_vf;
@@ -454,11 +454,10 @@ static int i40e_config_iwarp_qvlist(struct i40e_vf *vf,
                goto err_out;
        }
 
-       size = sizeof(struct virtchnl_iwarp_qvlist_info) +
-              (sizeof(struct virtchnl_iwarp_qv_info) *
-                                               (qvlist_info->num_vectors - 1));
        kfree(vf->qvlist_info);
-       vf->qvlist_info = kzalloc(size, GFP_KERNEL);
+       vf->qvlist_info = kzalloc(struct_size(vf->qvlist_info, qv_info,
+                                             qvlist_info->num_vectors - 1),
+                                 GFP_KERNEL);
        if (!vf->qvlist_info) {
                ret = -ENOMEM;
                goto err_out;
@@ -1846,7 +1845,7 @@ static int i40e_vc_get_vf_resources_msg(struct i40e_vf *vf, u8 *msg)
        i40e_status aq_ret = 0;
        struct i40e_vsi *vsi;
        int num_vsis = 1;
-       int len = 0;
+       size_t len = 0;
        int ret;
 
        if (!test_bit(I40E_VF_STATE_INIT, &vf->vf_states)) {
@@ -1854,9 +1853,7 @@ static int i40e_vc_get_vf_resources_msg(struct i40e_vf *vf, u8 *msg)
                goto err;
        }
 
-       len = (sizeof(struct virtchnl_vf_resource) +
-              sizeof(struct virtchnl_vsi_resource) * num_vsis);
-
+       len = struct_size(vfres, vsi_res, num_vsis);
        vfres = kzalloc(len, GFP_KERNEL);
        if (!vfres) {
                aq_ret = I40E_ERR_NO_MEMORY;