From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Wolfram Sang <wsa@the-dreams.de>,
linux-iio@vger.kernel.orgi, Luca Ceresoli <luca@lucaceresoli.net>,
linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 3/3] i2c: smbus: switch from loops to memcpy
Date: Mon, 18 Nov 2019 08:47:57 +0100 [thread overview]
Message-ID: <20191118074757.edyfvz5s3pqnu67y@pengutronix.de> (raw)
In-Reply-To: <20191112203132.163306-4-dmitry.torokhov@gmail.com>
Hello Dmitry,
On Tue, Nov 12, 2019 at 12:31:32PM -0800, Dmitry Torokhov wrote:
> When copying memory from one buffer to another, instead of open-coding
> loops with byte-by-byte copies let's use memcpy() which might be a bit
> faster and makes intent more clear.
>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>
> ---
>
> Changes in v3:
> - new patch using memcpy() for moving data around
>
> drivers/i2c/i2c-core-smbus.c | 15 +++++----------
> 1 file changed, 5 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c
> index 7b4e2270eeda1..bbafdd3b1b114 100644
> --- a/drivers/i2c/i2c-core-smbus.c
> +++ b/drivers/i2c/i2c-core-smbus.c
> @@ -397,8 +397,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr,
> }
>
> i2c_smbus_try_get_dmabuf(&msg[0], command);
> - for (i = 1; i < msg[0].len; i++)
> - msg[0].buf[i] = data->block[i - 1];
> + memcpy(msg[0].buf + 1, data->block, msg[0].len - 1);
Can it happen that msg[0].len is zero?
> }
> break;
> case I2C_SMBUS_BLOCK_PROC_CALL:
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
next prev parent reply other threads:[~2019-11-18 7:48 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-12 20:31 [PATCH v3 0/3] Use void pointers instead of char in I2C transfer APIs Dmitry Torokhov
2019-11-12 20:31 ` [PATCH v3 1/3] i2c: use void pointers for supplying data for reads and writes Dmitry Torokhov
2019-11-13 9:47 ` Luca Ceresoli
2019-11-18 7:43 ` Uwe Kleine-König
2019-11-18 8:04 ` Dmitry Torokhov
2019-11-18 8:38 ` Uwe Kleine-König
2021-01-11 21:02 ` Wolfram Sang
2019-11-12 20:31 ` [PATCH v3 2/3] i2c: smbus: use get/put_unaligned_le16 when working with word data Dmitry Torokhov
2019-11-13 9:47 ` Luca Ceresoli
2019-11-13 19:39 ` Dmitry Torokhov
2019-11-14 9:23 ` Luca Ceresoli
2019-11-18 7:36 ` Uwe Kleine-König
2021-01-11 21:04 ` Wolfram Sang
2019-11-12 20:31 ` [PATCH v3 3/3] i2c: smbus: switch from loops to memcpy Dmitry Torokhov
2019-11-13 9:47 ` Luca Ceresoli
2019-11-18 7:47 ` Uwe Kleine-König [this message]
2019-11-18 8:09 ` Dmitry Torokhov
2019-11-18 8:47 ` Uwe Kleine-König
2021-01-11 21:04 ` Wolfram Sang
2021-01-11 21:01 ` [PATCH v3 0/3] Use void pointers instead of char in I2C transfer APIs Wolfram Sang
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