ixgbe: Use struct_size() helper

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index 62e6499..cc3196a 100644 (file)
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
@@ -836,12 +836,10 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
        struct ixgbe_ring *ring;
        int node = NUMA_NO_NODE;
        int cpu = -1;
-       int ring_count, size;
+       int ring_count;
        u8 tcs = adapter->hw_tcs;
 
        ring_count = txr_count + rxr_count + xdp_count;
-       size = sizeof(struct ixgbe_q_vector) +
-              (sizeof(struct ixgbe_ring) * ring_count);
 
        /* customize cpu for Flow Director mapping */
        if ((tcs <= 1) && !(adapter->flags & IXGBE_FLAG_SRIOV_ENABLED)) {
@@ -855,9 +853,11 @@ static int ixgbe_alloc_q_vector(struct ixgbe_adapter *adapter,
        }
 
        /* allocate q_vector and rings */
-       q_vector = kzalloc_node(size, GFP_KERNEL, node);
+       q_vector = kzalloc_node(struct_size(q_vector, ring, ring_count),
+                               GFP_KERNEL, node);
        if (!q_vector)
-               q_vector = kzalloc(size, GFP_KERNEL);
+               q_vector = kzalloc(struct_size(q_vector, ring, ring_count),
+                                  GFP_KERNEL);
        if (!q_vector)
                return -ENOMEM;