[PATCH][next] wifi: rtw89: coex: Fix -Wstringop-overflow warnings in _append_tdma()

From: Gustavo A. R. Silva
Date: Mon Nov 13 2023 - 14:35:59 EST


Copy a couple of structures directly, instead of using `memcpy()`.

This addesses the following -Wstringop-overflow warnings:
drivers/net/wireless/realtek/rtw89/coex.c: In function ‘_append_tdma’:
./include/linux/fortify-string.h:57:33: warning: writing 8 bytes into a region of size 0 [-Wstringop-overflow=]
57 | #define __underlying_memcpy __builtin_memcpy
| ^
./include/linux/fortify-string.h:644:9: note: in expansion of macro ‘__underlying_memcpy’
644 | __underlying_##op(p, q, __fortify_size); \
| ^~~~~~~~~~~~~
./include/linux/fortify-string.h:689:26: note: in expansion of macro ‘__fortify_memcpy_chk’
689 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \
| ^~~~~~~~~~~~~~~~~~~~
drivers/net/wireless/realtek/rtw89/coex.c:1585:17: note: in expansion of macro ‘memcpy’
1585 | memcpy(&v3->tdma, &dm->tdma, sizeof(v3->tdma));
| ^~~~~~
drivers/net/wireless/realtek/rtw89/core.h:2703:37: note: at offset [5714, 71249] into destination object ‘ver’ of size 8
2703 | const struct rtw89_btc_ver *ver;
| ^~~
./include/linux/fortify-string.h:57:33: warning: writing 8 bytes into a region of size 0 [-Wstringop-overflow=]
57 | #define __underlying_memcpy __builtin_memcpy
| ^
./include/linux/fortify-string.h:644:9: note: in expansion of macro ‘__underlying_memcpy’
644 | __underlying_##op(p, q, __fortify_size); \
| ^~~~~~~~~~~~~
./include/linux/fortify-string.h:689:26: note: in expansion of macro ‘__fortify_memcpy_chk’
689 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \
| ^~~~~~~~~~~~~~~~~~~~
drivers/net/wireless/realtek/rtw89/coex.c:1579:17: note: in expansion of macro ‘memcpy’
1579 | memcpy(v, &dm->tdma, sizeof(*v));
| ^~~~~~
drivers/net/wireless/realtek/rtw89/core.h:2703:37: note: at offset [5710, 71245] into destination object ‘ver’ of size 8
2703 | const struct rtw89_btc_ver *ver;
| ^~~

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/net/wireless/realtek/rtw89/coex.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
index bdcc172639e4..b842cd9a86f8 100644
--- a/drivers/net/wireless/realtek/rtw89/coex.c
+++ b/drivers/net/wireless/realtek/rtw89/coex.c
@@ -1576,13 +1576,13 @@ static void _append_tdma(struct rtw89_dev *rtwdev)
if (ver->fcxtdma == 1) {
v = (struct rtw89_btc_fbtc_tdma *)&tlv->val[0];
tlv->len = sizeof(*v);
- memcpy(v, &dm->tdma, sizeof(*v));
+ *v = dm->tdma;
btc->policy_len += BTC_TLV_HDR_LEN + sizeof(*v);
} else {
tlv->len = sizeof(*v3);
v3 = (struct rtw89_btc_fbtc_tdma_v3 *)&tlv->val[0];
v3->fver = ver->fcxtdma;
- memcpy(&v3->tdma, &dm->tdma, sizeof(v3->tdma));
+ v3->tdma = dm->tdma;
btc->policy_len += BTC_TLV_HDR_LEN + sizeof(*v3);
}

--
2.34.1