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 <gust...@embeddedor.com>
---
drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
b/drivers/net/ethernet/intel/ixgbe/ixgbe_lib.c
index 62e6499e4146..cc3196ae5aea 100644
--- 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;
--
2.20.1
