iavf: 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 bufsz 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/iavf/iavf_main.c b/drivers/net/ethernet/intel/iavf/iavf_main.c
index 4569d69..78340b2 100644 (file)
--- a/drivers/net/ethernet/intel/iavf/iavf_main.c
+++ b/drivers/net/ethernet/intel/iavf/iavf_main.c
@@ -3353,7 +3353,7 @@ static void iavf_init_task(struct work_struct *work)
        struct net_device *netdev = adapter->netdev;
        struct iavf_hw *hw = &adapter->hw;
        struct pci_dev *pdev = adapter->pdev;
-       int err, bufsz;
+       int err;
 
        switch (adapter->state) {
        case __IAVF_STARTUP:
@@ -3423,10 +3423,9 @@ static void iavf_init_task(struct work_struct *work)
        case __IAVF_INIT_GET_RESOURCES:
                /* aq msg sent, awaiting reply */
                if (!adapter->vf_res) {
-                       bufsz = sizeof(struct virtchnl_vf_resource) +
-                               (IAVF_MAX_VF_VSI *
-                                sizeof(struct virtchnl_vsi_resource));
-                       adapter->vf_res = kzalloc(bufsz, GFP_KERNEL);
+                       adapter->vf_res = kzalloc(struct_size(adapter->vf_res,
+                                                 vsi_res, IAVF_MAX_VF_VSI),
+                                                 GFP_KERNEL);
                        if (!adapter->vf_res)
                                goto err;
                }