* [PATCH net-next] igc: Use struct_size() helper
@ 2019-02-08 4:19 Gustavo A. R. Silva
2019-02-09 7:04 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Gustavo A. R. Silva @ 2019-02-08 4:19 UTC (permalink / raw)
To: Jeff Kirsher, David S. Miller
Cc: intel-wired-lan, netdev, linux-kernel, Gustavo A. R. Silva
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>
---
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net-next] igc: Use struct_size() helper
2019-02-08 4:19 [PATCH net-next] igc: Use struct_size() helper Gustavo A. R. Silva
@ 2019-02-09 7:04 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2019-02-09 7:04 UTC (permalink / raw)
To: gustavo; +Cc: jeffrey.t.kirsher, intel-wired-lan, netdev, linux-kernel
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Thu, 7 Feb 2019 22:19:45 -0600
> 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>
Applied.
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