linux-kernel - [PATCH net-next] wifi: wcn36xx: Slightly optimize PREPARE_HAL

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Date:   Thu,  2 Feb 2023 21:58:10 +0100
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     Loic Poulain <loic.poulain@...aro.org>,
        Kalle Valo <kvalo@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>
Cc:     linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>,
        wcn36xx@...ts.infradead.org, linux-wireless@...r.kernel.org,
        netdev@...r.kernel.org
Subject: [PATCH net-next] wifi: wcn36xx: Slightly optimize PREPARE_HAL_BUF()

In most (likely all) cases, INIT_HAL_MSG() is called before
PREPARE_HAL_BUF().
In such cases calling memset() is useless because:
   msg_body.header.len = sizeof(msg_body)

So, instead of writing twice the memory, we just have a sanity check to
make sure that some potential trailing memory is zeroed.
It even gives the opportunity to see that by itself and optimize it away.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
 drivers/net/wireless/ath/wcn36xx/smd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/wcn36xx/smd.c b/drivers/net/wireless/ath/wcn36xx/smd.c
index 566f0b9c1584..17e1919d1cd8 100644
--- a/drivers/net/wireless/ath/wcn36xx/smd.c
+++ b/drivers/net/wireless/ath/wcn36xx/smd.c
@@ -475,8 +475,8 @@ static int wcn36xx_smd_send_and_wait(struct wcn36xx *wcn, size_t len)
 
 #define PREPARE_HAL_BUF(send_buf, msg_body) \
 	do {							\
-		memset(send_buf, 0, msg_body.header.len);	\
-		memcpy(send_buf, &msg_body, sizeof(msg_body));	\
+		memcpy_and_pad(send_buf, msg_body.header.len,	\
+			       &msg_body, sizeof(msg_body), 0);	\
 	} while (0)						\
 
 #define PREPARE_HAL_PTT_MSG_BUF(send_buf, p_msg_body) \
-- 
2.34.1