On 12/16/22 3:29 PM, Martin KaFai Lau wrote:
From: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
'struct bpf_local_storage_elem' has a 56 bytes padding at the end
which can be used for attr->value_size. The current smap->elem_size
'can be' => 'will be'?
calculation is unnecessarily inflated by 56 bytes.
The patch is to fix it by calculating the smap->elem_size
with offsetof().
Signed-off-by: Martin KaFai Lau <martin.lau@xxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
---
kernel/bpf/bpf_local_storage.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index b39a46e8fb08..cb43e70613b1 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -580,8 +580,8 @@ static struct bpf_local_storage_map *__bpf_local_storage_map_alloc(union bpf_att
raw_spin_lock_init(&smap->buckets[i].lock);
}
- smap->elem_size =
- sizeof(struct bpf_local_storage_elem) + attr->value_size;
+ smap->elem_size = offsetof(struct bpf_local_storage_elem, sdata) +
+ offsetof(struct bpf_local_storage_data, data[attr->value_size]);
return smap;
}
