From: Loic Poulain <loic.poulain@linaro.org>
To: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Kalle Valo <kvalo@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org,
wcn36xx@lists.infradead.org, linux-wireless@vger.kernel.org,
netdev@vger.kernel.org
Subject: Re: [PATCH net-next] wifi: wcn36xx: Slightly optimize PREPARE_HAL_BUF()
Date: Sun, 5 Feb 2023 14:18:07 +0100 [thread overview]
Message-ID: <CAMZdPi-hUyorX6N-3koxOZ+gSxovdQc7iKxx7wuN+qJek_cvCA@mail.gmail.com> (raw)
In-Reply-To: <7d8ab7fee45222cdbaf80c507525f2d3941587c1.1675371372.git.christophe.jaillet@wanadoo.fr>
On Thu, 2 Feb 2023 at 21:58, Christophe JAILLET
<christophe.jaillet@wanadoo.fr> wrote:
>
> 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@wanadoo.fr>
Acked-by: Loic Poulain <loic.poulain@linaro.org>
> ---
> 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
>
next prev parent reply other threads:[~2023-02-05 13:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-02 20:58 [PATCH net-next] wifi: wcn36xx: Slightly optimize PREPARE_HAL_BUF() Christophe JAILLET
2023-02-05 13:18 ` Loic Poulain [this message]
2023-02-24 10:22 ` Kalle Valo
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