* [PATCH] lib: objagg: Use struct_size() in kzalloc()
@ 2019-06-05 14:45 Gustavo A. R. Silva
2019-06-05 15:21 ` Jiri Pirko
2019-06-06 2:03 ` David Miller
0 siblings, 2 replies; 3+ messages in thread
From: Gustavo A. R. Silva @ 2019-06-05 14:45 UTC (permalink / raw)
To: Jiri Pirko; +Cc: 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 objagg_stats {
...
struct objagg_obj_stats_info stats_info[];
};
size = sizeof(*objagg_stats) + sizeof(objagg_stats->stats_info[0]) * count;
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, stats_info, count), GFP_KERNEL);
Notice that, in this case, variable alloc_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>
---
lib/objagg.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/lib/objagg.c b/lib/objagg.c
index 576be22e86de..55621fb82e0a 100644
--- a/lib/objagg.c
+++ b/lib/objagg.c
@@ -605,12 +605,10 @@ const struct objagg_stats *objagg_stats_get(struct objagg *objagg)
{
struct objagg_stats *objagg_stats;
struct objagg_obj *objagg_obj;
- size_t alloc_size;
int i;
- alloc_size = sizeof(*objagg_stats) +
- sizeof(objagg_stats->stats_info[0]) * objagg->obj_count;
- objagg_stats = kzalloc(alloc_size, GFP_KERNEL);
+ objagg_stats = kzalloc(struct_size(objagg_stats, stats_info,
+ objagg->obj_count), GFP_KERNEL);
if (!objagg_stats)
return ERR_PTR(-ENOMEM);
--
2.21.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] lib: objagg: Use struct_size() in kzalloc()
2019-06-05 14:45 [PATCH] lib: objagg: Use struct_size() in kzalloc() Gustavo A. R. Silva
@ 2019-06-05 15:21 ` Jiri Pirko
2019-06-06 2:03 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: Jiri Pirko @ 2019-06-05 15:21 UTC (permalink / raw)
To: Gustavo A. R. Silva; +Cc: Jiri Pirko, netdev, linux-kernel
Wed, Jun 05, 2019 at 04:45:16PM CEST, gustavo@embeddedor.com wrote:
>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 objagg_stats {
> ...
> struct objagg_obj_stats_info stats_info[];
>};
>
>size = sizeof(*objagg_stats) + sizeof(objagg_stats->stats_info[0]) * count;
>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, stats_info, count), GFP_KERNEL);
>
>Notice that, in this case, variable alloc_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>
Acked-by: Jiri Pirko <jiri@mellanox.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] lib: objagg: Use struct_size() in kzalloc()
2019-06-05 14:45 [PATCH] lib: objagg: Use struct_size() in kzalloc() Gustavo A. R. Silva
2019-06-05 15:21 ` Jiri Pirko
@ 2019-06-06 2:03 ` David Miller
1 sibling, 0 replies; 3+ messages in thread
From: David Miller @ 2019-06-06 2:03 UTC (permalink / raw)
To: gustavo; +Cc: jiri, netdev, linux-kernel
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
Date: Wed, 5 Jun 2019 09:45:16 -0500
> 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 objagg_stats {
> ...
> struct objagg_obj_stats_info stats_info[];
> };
>
> size = sizeof(*objagg_stats) + sizeof(objagg_stats->stats_info[0]) * count;
> 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, stats_info, count), GFP_KERNEL);
>
> Notice that, in this case, variable alloc_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.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-06-05 14:45 [PATCH] lib: objagg: Use struct_size() in kzalloc() Gustavo A. R. Silva
2019-06-05 15:21 ` Jiri Pirko
2019-06-06 2:03 ` David Miller
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