[PATCH][next] net: sched: cls_u32: Fix allocation in u32_init()

From: Gustavo A. R. Silva
Date: Thu Aug 17 2023 - 11:58:46 EST


Replace struct_size() with sizeof(), and avoid allocating 8 too many
bytes.

The following difference in binary output is expected and reflects the
desired change:

| net/sched/cls_u32.o
| @@ -6148,7 +6148,7 @@
| include/linux/slab.h:599
| 2cf5: mov 0x0(%rip),%rdi # 2cfc <u32_init+0xfc>
| 2cf8: R_X86_64_PC32 kmalloc_caches+0xc
|- 2cfc: mov $0x98,%edx
|+ 2cfc: mov $0x90,%edx

Fixes: d61491a51f7e ("net/sched: cls_u32: Replace one-element array with flexible-array member")
Reported-by: Alejandro Colomar <alx@xxxxxxxxxx>
Closes: https://lore.kernel.org/lkml/09b4a2ce-da74-3a19-6961-67883f634d98@xxxxxxxxxx/
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
net/sched/cls_u32.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index da4c179a4d41..6663e971a13e 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -366,7 +366,7 @@ static int u32_init(struct tcf_proto *tp)
idr_init(&root_ht->handle_idr);

if (tp_c == NULL) {
- tp_c = kzalloc(struct_size(tp_c, hlist->ht, 1), GFP_KERNEL);
+ tp_c = kzalloc(sizeof(*tp_c), GFP_KERNEL);
if (tp_c == NULL) {
kfree(root_ht);
return -ENOBUFS;
--
2.34.1