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/igc/igc_main.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c
b/drivers/net/ethernet/intel/igc/igc_main.c
index 11c75433fe22..87a11879bf2d 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -2958,22 +2958,21 @@ static int igc_alloc_q_vector(struct igc_adapter
*adapter,
{
struct igc_q_vector *q_vector;
struct igc_ring *ring;
- int ring_count, size;
+ int ring_count;
/* igc only supports 1 Tx and/or 1 Rx queue per vector */
if (txr_count > 1 || rxr_count > 1)
return -ENOMEM;
ring_count = txr_count + rxr_count;
- size = sizeof(struct igc_q_vector) +
- (sizeof(struct igc_ring) * ring_count);
/* allocate q_vector and rings */
q_vector = adapter->q_vector[v_idx];
if (!q_vector)
- q_vector = kzalloc(size, GFP_KERNEL);
+ q_vector = kzalloc(struct_size(q_vector, ring, ring_count),
+ GFP_KERNEL);
else
- memset(q_vector, 0, size);
+ memset(q_vector, 0, struct_size(q_vector, ring, ring_count));
if (!q_vector)
return -ENOMEM;
--
2.20.1
